Entropy-mediated solidification stabilizes and enhances energetic release in amorphous energetic materials

Domain: neuroscience
Published: 2026-02-11
Editorial outcome: major_revision

Abstract
The formation of stable amorphous phases in rigid organic small molecules is fundamentally hindered by their pronounced crystallization tendency. This challenge is particularly acute in energetic materials, in which the amorphous phase must be stabilized without inert additives to preserve high energy density. Here, we overcome this longstanding obstacle by realising a stable amorphous energetic material based on the small molecule explosive (4,4′,5,5′-tetranitro-1H,1′H-2,2′-biimidazole-1,1′-diamine, DATNBI). The amorphous DATNBI (AEM-DATNBI) prepared via a melt quenching process, exhibits a glass transition temperature of 59.67 °C and demonstrates remarkable structural stability below this threshold, maintaining its integrity for over 24 hours at 60 °C. This stability originates from a synergistic interaction between the non-planar molecular framework and a three-dimensional hydrogen-bond network formed by -NH₂/-NO₂ groups. This unique amorphous structure not only enhances safety by suppressing hotspot formation but also accelerates energy release, leading to faster combustion and more complete decomposition. This study demonstrates a general strategy leveraging steric hindrance and intermolecular interactions, thereby extending the realm of amorphous materials to energetic compounds and other functional rigid organic small molecules.

Introduction
Amorphous materials, as non-equilibrium metastable phases, exhibit immense application potential in fields such as optics1,2, energy3 and biomedicine4,5 due to their unique disordered structure and solid-like mechanical response6,7. The structural characteristic of such materials is short-range order coupled with long-range disorder, manifesting as isotropic behaviour and the absence of a fixed melting point. According to the Kauzmann hypothesis, virtually all materials possess the potential to form an amorphous state under specific conditions8. The key prerequisite for forming an amorphous state is that the glass transition must occur before the system cools to the Kauzmann temperature. This theory provides fundamental principles for designing novel amorphous materials, driving research beyond traditional silicates to encompass diverse systems including polymers9, metal-organic frameworks10,11, and inorganic salts12,13. Despite considerable progress in the study of amorphous materials, achieving stable amorphous states in rigid organic small molecules remains a formidable challenge. While these molecules are simple in structure and highly designable, their strong crystallisation tendency leads to readily occurring crystallisation during melt cooling, resulting in poor processability14–16. The current research mostly focuses on molecules featuring extended carbon chains, multi-aromatic ring structures, or conformational flexibility17, employing strategies such as small molecule co-formants or polymer blends to enhance amorphous formation capability18,19. However, there is currently limited research available on the amorphous transformation processes of simpler, low-molecular-weight monocyclic or bicyclic rigid organic small molecules.

Energetic materials, which are organic small molecules that combine high rigidity, high energy density, and tunable weak intermolecular interactions (e.g., hydrogen bonding via nitro/amino groups), represent an ideal model system for addressing the challenge of preparing amorphous organic small molecules20–23. Critically, achieving their amorphization holds promise for delivering multiple breakthrough advantages (Figure 1). For instance, it could circumvent the safety and reliability issues associated with crystalline defects (e.g., anisotropy, dislocations, impurities)24,25. Furthermore, while retaining the intrinsic high energy density26, the disordered structure offers a new dimension for modulating energy release and sensitivity. Additionally, amorphization unlocks advanced processability (enabling techniques like hot-pressing or 3D printing) and potential novel functionalities, such as self-healing and stimuli-responsive behavior27. As opposed to the amorphisation of pharmaceuticals aimed at enhancing bioavailability28,29, the amorphisation of energetic systems strives to be achieved without the addition of external components to maintain energy density without compromise30,31. This specific requirement makes the amorphisation of energetic materials a particularly formidable challenge. To date, only a limited number of energetic molecules (such as 2,4,6-trinitrotoluene (TNT), pentaerythritol tetranitrate (PETN), and 2,2',4,4',6,6'-hexanitroazobenzene (HNAB)) have been successfully amorphised through specific methods, which suffer from issues including poor stability, susceptibility to recrystallisation32–34. A significant advancement was marked by the work of the US Navy's Stepanov team, who developed amorphous composites based on hexanitrohexaazaisowurtzitane (CL-20) and 1,3,5,7-tetranitro-1,3,5,7-tetrazoctane (HMX) using polyvinyl acetate (PVAc) as a dispersant. Nevertheless, the introduction of such non-energetic dispersants inevitably leads to a loss of overall energy35.

The fundamental challenge in amorphising energetic materials is their molecular structural characteristics. Conventional energetic compounds typically possess linear or monocyclic frameworks alongside limited molecular conformational diversity36–38. These structural features predispose them towards the formation of ordered crystalline structures. In comparison, drug molecules that successfully achieve amorphisation often possess multi-ring skeletons, branched structures, and multiple functional groups. These characteristics confer significant conformational diversity and steric hindrance upon the molecules, effectively inhibiting regular packing14,39. This comparison underscore an intrinsic link between molecular structural features and the propensity for amorphous phase formation. Among known rigid energy-rich molecules, there may be potential amorphous formers that inherently possess ‘structural frustration’ properties. The potential of these molecules stems from their intrinsic structural features, such as non-planar configurations, asymmetric frameworks, and complex hydrogen bonding.

This work focuses on a series of explosive systems with well-defined structural features. We propose a strategy based on functional group engineering to modulate molecular planarity, molecular interactions, and steric hindrance, successfully constructing an amorphous explosive. The amorphous DATNBI (AEM-DATNBI) prepared via this method exhibits a completely amorphous and homogeneous nature, with a glass transition temperature (T ) of 60 °C. This result is significantly superior to the amorphous trinitrotoluene (T = -25.6 °C) reported in the literature32, with substantially enhanced physical stability. Compared to its crystalline counterpart, AEM-DATNBI demonstrates lower mechanical sensitivity and higher energy release efficiency. This strategy not only establishes a foundation for developing next-generation energetic materials characterized by stable performance, enriched functionality, and flexible processing, but also provides a successful paradigm for addressing the central challenge of poor glass formation inherent to rigid small molecules. The emergence of amorphous energetic materials pioneers an unexplored research area in explosives science. Its significance extends beyond the discovery of a novel material, representing a promising direction for research and industry.

Results
To elucidate the role of key molecular structures in regulating amorphous phase formation during melt-processable energetic compounds40–43. we conducted a systematic investigation of representative small-molecule explosives spanning three structural classes (imidazole derivatives, benzene derivatives, and polycyclic compounds) (Supplementary Fig. 1). To investigate the phase transition behavior, the melts were rapidly cooled at 50 K/min (Supplementary Fig. 2–4). The DSC cooling curves reveal crystallisation exothermic peaks (the crystallization temperature, T ) for 4-methoxy-1-methyl-3,5-dinitro-1 H -pyrazole (DMDNP), 1,3-dinitrobenzene (DNB), 2,4-dinitroanisole (DNAN) and benzotrifuroxan (BTF) during cooling (Supplementary Fig. 2c-d, 3d, 4b). This phenomenon indicates that even at high cooling rates, these compounds exhibit a strong tendency to form ordered crystalline structures. In stark contrast, the T of 3,4-dinitropyrazole (DNP), 1-methyl-3,4,5-trinitropyrazole (MTNP), 2,4,6-trinitro-3,5-difluorophenyl methyl ether (DFTNAN), and 3,4-dinitrofurazanfuroxan (DNT F) were not detected during cooling (Supplementary Fig. 2b, 3a-b, 4a), suggesting their melts may be supercooled and form metastable amorphous states (supercooled liquids or glassy states). Subsequent reheating confirmed that DNP, DFTNAN, and DNTF each exhibited distinct endothermic transitions corresponding to the glass transition temperature (T ), thereby verifying their glassy state. After subsequent heating, distinct crystallization exothermic peaks (T ) were observed at -7.82 °C, 26.53 °C, 27.30 °C, and 24.18 °C for DFTNAN, DNP, MTNP, and DNTF, respectively. This result clearly indicates that as the temperature rises to near ambient conditions, molecules acquire sufficient kinetic energy to drive the system from a disordered metastable state to ordered crystalline structure. Therefore, these amorphous phases lack the necessary structural stability within typical operating temperature ranges (e.g., room temperature to 50 °C), limiting their practical application prospects.

In order to investigate the decisive factors governing the formation and stability of amorphous structures at the molecular level, the molecular planarity parameter (MPP) and molecular surface deviation (SDP) were introduced to quantify the planar characteristics of molecules44. Smaller values indicate that the molecular structure is closer to a perfect planar configuration. The analysis indicates that molecules exhibiting strong crystallisation tendencies, such as DMDNP, DNB, DNAN, and BTF, possess a greater planarity. Conversely, the molecules DNP, MTNP, DFTNAN, and DNTF, which form amorphous states upon rapid cooling, show greater atomic deviation from the plane and poorer planarity. These results suggest that reduced molecular planarity (molecular planarity parameter, MPP > 0.3) is a key initial factor in suppressing crystallization and promoting amorphous phase formation (Supplementary Fig. 5 and Supplementary Table 1). This is because non-planar structures (such as the steric hindrance of methoxy groups in DNAN or the rotatable flexible furan ring in DNTF) effectively increase steric hindrance, thereby impeding the formation of ordered lattices. However, non-planarity alone is insufficient to achieve physically stable amorphous structures with practical utility. DNP exhibits high molecular rigidity, lacks flexible functional groups, possesses poor planarity (MPP = 0.367), and successfully forms an amorphous state. Notably, the glass transition temperature (T ) of the amorphous DNP (T = −19.67 °C) is higher than that of the DFTNAN, which exhibits poorer planarity (MPP = 0.519, T = −46.48 °C). We speculate that this may be due to the presence of both hydrogen bond donors and acceptors within DNP, which form intermolecular hydrogen bonds. This is crucial for inhibiting the ordered rearrangement of molecules and enhancing the stability of the amorphous state.

With the above understanding, the amorphous organic small molecules can be successfully synthesised from the synergy of multiple factors. This can be achieved by modulating the molecular backbone and functional groups to reduce molecular planarity, whilst simultaneously introducing hydrogen bond donors and acceptors to enhance intermolecular interactions. Under this design principle, DATNBI was selected as the model molecule for preparing structurally stable amorphous energetic materials. Its advantage lies in the conformational complexity imparted by its double imidazole skeleton, which further increases steric hindrance (Supplementary Fig. 6) and restricts the freedom of molecular motion. Moreover, DATNBI incorporates both diamino (strong hydrogen bond donors) and dinitro (strong hydrogen bond acceptors) groups within its molecular structure. This configuration provides multiple hydrogen bonding sites, facilitating the formation of a stronger, more stable intermolecular hydrogen bond network.

Amorphous DATNBI (AEM-DATNBI) was constructed through single-crystal thermal phase transition pathway, crystalline DATNBI (CEM-DATNBI) was melted at 263 °C and then rapidly quenched to freeze its disordered state (Figure 2a). AEM-DATNBI exhibited a significantly higher glass transition temperature (T = 59.67 °C) and a cold crystallization exotherm occurring at 98.26 °C (Figure 2b). This elevated T and cold-crystallization temperature indicate that DATNBI can maintain a stable amorphous state over a substantially wider temperature window compared to the other glass formers32. Polarized optical microscopy (POM) provided compelling visual evidence for the structural transformation. CEM-DATNBI showed birefringence-induced coloration (Supplementary Fig. 7a), contrasting sharply with the featureless dark field of its amorphous counterpart (Supplementary Fig. 7b), confirming isotropic structural homogeneity. At the microscale, CEM-DATNBI appeared as cubic structures with significant surface roughness and defects (Supplementary Fig. 8), whereas the amorphous solid presented as smooth, dense, and uniform irregular blocks (Figure 2a). Furthermore, X-ray diffraction (XRD) patterns revealed the disappearance of characteristic diffraction signals from crystalline DATNBI in AEM-DATNBI, with broad peaks observed at 17.1° and 23.5° (Figure 2c), marking the dissolution of long-range order and the establishment of the amorphous state. The room temperature X-ray total scattering of AEM-DATNBPI was further performed to study its structural characteristic. Subsequent normalized, and Fourier transformed yielded the radial distribution function (RDF) (Supplementary Fig. 9a). RDF results demonstrate that distinct peaks at short-range distances (<5 Å) from molecular aggregation, while the weakening of peaks beyond 5 Å confirmed the absence of periodic packing. Molecular dynamics (MD) simulations corroborated these observations (Supplementary Fig. 9b).

Critically, spectroscopic and chromatographic analyses confirmed unaltered molecular integrity. FTIR spectra (Figure 2d) showed identical functional group signatures between crystalline and amorphous states, though N-H stretching (3250 cm⁻¹) and bending modes (1500–1625 cm⁻¹) shifted due to hydrogen-bond reorganization and conformational polymorphism45,46. Consistency in HPLC retention times (Supplementary Fig. 10) and molecular weights (Supplementary Fig. 11) ruled out degradation. Calculated chemical purity exceeds 99.8% (external standard method) (Supplementary Fig. 12 and Supplementary Table 2). Furthermore, the chemical shifts of the imidazole ring in the 13C NMR spectra of AEM-DATNBI were found at 135.7, 134.3, and 131.6 ppm. The corresponding 1H NMR signal appeared at 6.98 ppm (Supplementary Fig. 13). These values are very similar to those of CEM-DATNBI47,48, further confirming that the amorphisation process has not disrupted its chemical structure.

Structural stability of AEM-DATNBI
Following confirmation of the amorphous structure and molecular integrity of AEM-DATNBI, its structural stability was further investigated. It starts to transform into a crystalline state when heated to 90 °C, as evidenced by XRD peaks matching those of α-DATNBI and γ-DATNBI (Figure 2e). The diffraction pattern at 100 °C revealed multiple sharp peaks, corresponding to the representative diffraction peaks of α-, β-, and γ-phases. It is easy to understand that the molecular mobility increases above the T prompting conformational rearrangement, driving the transition from amorphous to crystalline states. This process visually captured by POM (Supplementary Fig. 14), where isotropic amorphous regions transformed into birefringent crystalline domains. With heated induction crystallisation observed, we systematically evaluated the isothermal stability of amorphous AEM-DATNBI, focusing on its behavior near and above the glass transition temperature (T ). Close to the T (59.8 °C), AEM-DATNBI exhibited excellent structural stability over 24 hours at 60 °C. The stacked XRD patterns at 60°C (Figure 2f) consistently displayed a broad halo indicative of long-range disorder. As the isothermal test temperature increased to 100 °C (Supplementary Fig. 15), the physical stability of AEM-DATNBI progressively diminished, correlating with enhanced molecular mobility due to thermal activation above the T . Notably, during isothermal crystallization at 100 °C, AEM-DATNBI preferentially yielded γ-phase crystals (Supplementary Fig. 15d). This suggests that controlled isothermal crystallization of AEM-DATNBI can facilitate a rapid and straightforward conversion to γ-DATNBI.

To more realistically simulate temperature fluctuations in practical applications, the response of the material to dynamic thermal cycling was further investigated. The non-isothermal cycle (30 °C → 80 °C) revealed dynamic phase transition behavior (Figure 2g and Supplementary Fig. 16). The amorphous structure was maintained during heating, whereas subsequent cooling initiated the transformation of AEM-DATNBI towards a crystalline state (Figure 2g). This is attributed to the softening of AEM-DATNBI near its glass transition temperature (59.67 °C). The molecules undergo kinetically controlled rearrangement during cooling, transforming the local structure from short-range order to long-range order. Compared to prior work, such as the amorphization of PETN49, HNAB33, and TNT32, AEM-DATNBI exhibited relatively a better structural stability within the permissible temperature range (30-60 ℃). This structural stability is likely attributable to the fact that DATNBI possesses both amino and nitro groups form a three-dimensional hydrogen-bond network. This network impedes molecular rearrangement, thereby stabilising the amorphous phase, as corroborated by Supplementary Fig. 17. While AEM-DATNBI has achieved a degree of structural stability, further improvements are necessary to ensure that amorphous energetic materials remain stable under complex and variable application conditions.

Mechanism of AEM-DATNBI Formation
To further elucidate the formation mechanism of amorphous DATNBI, the real-time polarized optical microscopy (POM) captured its transition from crystalline to amorphous states. The β-DATNBI (crystalline state) first evolves into defective α-phase crystals (30-150 °C), followed by γ-phase restructuring (170-190 °C). The lattice structure is destroyed above 236°C, transitioning to a molten state. Finally, the molecule freezes to form an amorphous state upon quenching (Figure 3a). The structural evolution from crystalline to amorphous states is clearly documented in the in situ XRD patterns (Supplementary Fig. 18). During this process, the sharp β-phase diffraction peak successively undergoes α-phase and γ-phase transitions, ultimately disappearing entirely after melt quenching. This is replaced by broadened diffuse peaks at 17.1° and 23.5°, which confirm the destruction of the long-range ordered structure and amorphous formation. This process aligns with previous studies by our group on the polymorphic transitions of DATNBI50. At the crystalline level, the molecular packing pattern evolves from the wavy spatial arrangement of β-DATNBI to the cross-grid arrangement of γ-DATNBI, ultimately transforming into a completely disordered amorphous structure (Figure 3b). Infrared spectroscopy analysis revealed significant differences in the vibrational modes of -NH₂ groups among different polymorphs, particularly in the peak positions within the ranges of 3250 cm⁻¹ (N-H stretching vibration) and 1625–1500 cm⁻¹ (N-H bending vibration) (Figure 3c-d). The infrared absorption bands of AEM-DATNBI closely resemble those of γ-DATNBI, indicating that while it exhibits long-range disorder, it forms short-range cluster-like structures analogous to γ-DATNBI. This structural similarity facilitates amorphous phase formation. The infrared absorption frequencies of N-H (3361.3 cm⁻¹ and 929.5 cm⁻¹), N-C (1376.4 cm⁻¹), and -NO2 (1056.8 cm⁻¹) showed significant shifts compared to the crystalline state. The red-shifted N-O vibrational frequency indicates that the hydrogen bonding between N-H and O-N has been strengthened. Molecular dynamics simulations further confirmed an increase in the number of hydrogen bonds (Figure 3e), while the blue-shifted bending vibration frequency of N-H reflected the constraints imposed by random molecular arrangements on vibrations. In summary, the stable amorphous state achievable by DATNBI arises from the synergistic interplay between molecular architecture, intermolecular interactions, and phase transition kinetics. In terms of molecular engineering, the non-planar backbone disrupts crystalline packing, while dual functional groups (–NH₂/–NO₂) construct a robust hydrogen-bonding network. On the phase transition kinetics, thermally induced lattice disordering coupled with quenching captures the metastable state. In terms of conformational constraints, the distorted structure provides steric barrier effects, inhibiting molecular rearrangement and nucleation processes.

Self-healing capability and surface character of AEM-DATNBI
Interestingly, AEM-DATNBI exhibits temperature-activated self-repair capability, with surface cracks healing completely within 73 seconds at 60 °C, as directly observed by in situ optical microscopy at specific time intervals (Figure 4a). This phenomenon arises from hydrogen bond network reconfiguration enabled by softened molecular mobility. To further investigate the structural evolution of AEM-DATNBI during the self-healing process under in situ loading. The small-angle X-ray scattering (SAXS) to measure nanoscale pore defects in the solid (Supplementary Fig. 19 and 20). The SAXS results for AEM-DATNBI and CEM-DATNBI were converted into one-dimensional curves using Foxtort software, and the scattering data were corrected 51,52(Figure 4b-c). The scattering intensity of CEM-DATNBI was consistently higher than that of the amorphous phase. As the temperature gradually increased, the scattering intensity of the crystal remained almost unchanged, while that of AEM-DATNBI decreased by nearly an order of magnitude. Quantitative analysis of in situ SAXS data collected during heating from 30 °C to 110 °C revealed a total porosity reduction of 40.6% in the amorphous phase, while the crystalline phase showed a smaller decrease of 8.8%. Throughout this temperature range, the amorphous phase consistently exhibited lower porosity than the crystalline phase, as shown in Figure 4d. This distinctive microstructure effectively inhibits the formation of hot spots during impact and friction events, thus significantly mitigating the risk of accidental initiation. Thereby further unveiling its potential for practical applications.

Solid-solid surface contact phenomena are of critical importance in the processing and formulation development of explosives. We quantitatively evaluated binder compatibility through atomic-scale surface characterization, revealing fundamental differences between amorphous and crystalline systems. Atomic force microscopy (AFM) topographic analysis (Figure 4e) demonstrates that AEM-DATNBI achieves exceptional surface homogeneity with sub-nanometer roughness (R = 1.29 nm), contrasting sharply with layered growth patterns characteristic of CEM-DATNBI (R = 25.19 nm). This remarkable difference in surface morphology is attributed to the distinct structural arrangements of amorphous and crystalline phases. The enhanced interfacial adhesion of amorphous systems was quantified using F2314-functionalized AFM probes. Statistics and frequency counts are conducted to eliminate the random factors. Reliable tip-sample interaction force spectrum is obtained for CEM-DATNBI and AEM-DATNBI (Figure 4f and Supplementary Fig. 21). The adhesive force (F ) measured of CEM-DATNBI and AEM-DATNBI are 7.83 nN and 8.95 nN, respectively. This result showing 14.3% stronger binding forces compared to crystalline surface. These results provide important insights into interfacial interactions for explosive processing and formulation development. Contact angle measurements revealed the surface free energy of AEM-DATNBI was 38.3 mN/m, significantly lower than that of CEM-DATNBI (50.7 mN/m) (Figure 4g and Supplementary Fig. 22). The lower surface energy of AEM-DATNBI can be attributed to its disordered structure and high free volume53. The lack of long-range order in the amorphous phase allows surface molecules to rearrange and form lower energy configurations than in the crystalline phase, where rigid lattice structures restrict such restrict such motions.54. This structural flexibility contributes to the observed reduction in surface energy. The enhanced adhesion and lower surface energy of AEM-DATNBI suggest potential advantages in terms of enhancing structural stability and component adhesion capacity.

Energy Release and Mechanical sensitivity of AEM-DATNBI
As a specialized class of functional materials, the safety and energy release characteristics of explosives have long been a focal point of research. The thermal decomposition processes of AEM-DATNBI and CEM-DATNBI were evaluated using thermal gravimetric analysis (TGA) and differential scanning calorimetry (DSC). As shown in Figure 5a, CEM-DATNBI displayed an endothermic melt at 236.1 °C followed by decomposition peaks at 263.2 °C and 271.8 °C50. the amorphous counterpart exhibited exothermic decomposition at reduced temperatures (247.2 °C and 263.0 °C), reflecting a 10 °C destabilization of the decomposition threshold, demonstrating the destabilizing influence of amorphization on thermal stability. This phenomenon is likely due to amorphous substable state features. Crucially, AEM-DATNBI achieved near-complete mass loss (97.4%) compared to crystalline samples (77.3%, Figure 5b). This 20.1% increase in mass loss indicates that the decomposition reaction of amorphous DATNBI is more complete. The gaseous products generated during the preparation process were analyzed to gain a deeper understanding of its thermal decomposition mechanism. The FT-IR and pyrolysis-gas chromatography-mass spectrometry (PY-GCMS) spectra of their decomposition products are shown in Supplementary Fig. 23–24. It is observed from Supplementary Fig. 23 that the decomposition product types of AEM-DATNBI and CEM-DATNBI remain consistent, with primary gaseous products comprising N₂O, NO₂, NO, CO, CO₂, and H₂O. Supplementary Fig. 24 illustrates the relative concentration variations of several representative products. Compared to CEM-DATNBI, the gas products from AEM-DATNBI exhibit a significantly elevated relative concentration of N₂O/CO₂ (48% vs. 45%) and a marked increase in the relative concentration of NO (27% vs. 16%). Conversely, the relative content of CO decreased substantially (6% vs 26%). CO₂, and H₂O are products of highly oxidative processes, whereas CO signifies incomplete oxidation. This distribution clearly reflects the differences in the decomposition reaction pathways between AEM-DATNBI and CEM-DATNBI. Amorphous structures significantly influence the integrity of decomposition pathways by altering the local environment and diffusion behavior of reaction intermediates, thereby suppressing the formation of carbon-rich solid residues that are difficult to oxidize. Crystalline DATNBI (CEM-DATNBI) exhibits a dense, ordered molecular packing structure. During early pyrolysis, reactions may preferentially initiate at grain boundaries or defects. Partially oxidized intermediates (e.g., CO precursors) generated are restricted from diffusing out of the dense crystalline structure. These carbon-rich intermediates, “trapped” within or on the crystal surface, cannot fully contact oxygen for deep oxidation. Consequently, they are more prone to side reactions like polymerization and aromatization, ultimately forming highly thermally stable, non-volatile carbonaceous solid residues that resist further gasification. This explains the incomplete mass loss (77.3%) and relatively high CO yield. In contrast, amorphous DATNBI (AEM-DATNBI) exhibits a structure characterized by long-range disorder and large free volume. This structure provides more unobstructed pathways for the diffusion of reactants and intermediates. Consequently, intermediates generated during decomposition can rapidly diffuse and mix thoroughly with oxygen atoms originating from within the molecules, enabling a more complete oxidation reaction. This significantly suppresses the formation of carbon-rich solid residues, resulting in final reaction products consisting almost entirely of gaseous N₂O, CO₂, H₂O, and other components. Consequently, near-complete mass loss (97.4%) is achieved. In short, the difference in residue mass primarily stems from the amorphous structure inhibiting the formation of solid carbon residues, rather than simply altering the gas-phase ratio of CO and CO₂. The reduced CO yield results from more complete oxidation, not as a direct cause of decreased residues; the fundamental reason lies in the reaction pathway shifting toward more thorough oxidation, thereby avoiding the generation of solid carbon.

To quantify the energy landscape governing these processes, we employed Kissinger kinetics analysis on non-isothermal decomposition data (Figure 5c, Table 1, and Supplementary Fig. 25)55,56. It can be clearly seen that all fitted lines exhibit a good linear relationship (R2 > 0.96, Supplementary Table 3). The calculated activation energies demonstrate a 15.7% reduction for AEM-DATNBI (122.94 kJ·mol⁻¹) compared to CEM-DATNBI (145.91 kJ·mol⁻¹). This indicates that AEM-DATNBI requires less energy to activate molecules during decomposition, and amorphization helps reduce the energy barrier for thermal decomposition of the explosive, enhancing energy release characteristics. The findings align with the metastable energy state inherent to amorphous materials, providing fundamental understanding of structure-activity relationships in advanced energetic systems.

The impact tolerance increased by 150% (15 J vs. 6 J) and friction sensitivity (FS) reduced by 57% (252 N) compared to crystalline β-DATNBI counterparts (Fig. 5d). AEM-DATNBI exhibits a low mechanical sensitivity, which can be ascribled to its uniform internal structure and low-defect characteristics. These features reduce hot-spot nucleation in amorphous matrix. Further, using high-speed videography, we captured the flame combustion processes of CEM-DATNBI and AEM-DATNBI initiated by laser (Figure 5e). As shown in Figure 5e, AEM-DATNBI achieved a combustion rate of 56.5 mg/s, higher than that of CEM-DATNBI (45.2 mg/s), accompanied by intensified flame front propagation dynamics. This combustion superiority was further quantified through constant-volume chamber experiments measuring gas-generation kinetics (Figure 5f). The Pressure-time profiles revealed that AEM-DATNBI achieves faster initial pressurization rates (dP/dt) and 38% higher peak pressures than CEM-DATNBI (Figure 5g) demonstrating markedly enhanced reactivity. Notably, the observed single-stage gas release profile in amorphous systems contrasts with the multi-stage decomposition of crystalline materials, indicating optimized reaction continuity. This structural-kinetic relationship directly correlates with thermal decomposition activation energy reduction, confirming that amorphization establishes a continuous energy release pathway from thermolysis to combustion completion. Molecular-scale disorder eliminates lattice disruption energy barriers, accelerating combustion kinetics. It is evidenced the AEM-DATNBI achieving a 56.5 mg/s combustion rate, 25% faster than its crystalline counterpart (45.2 mg/s). and enhanced peak pressure in constant-volume tests. This metastable configuration concurrently lowers thermal decomposition activation energy (ΔE =122.94 kJ/mol), enabling rapid energy release.

Additionally, the detonation performance, as one of the core metrics for evaluating the application potential of explosives, was thoroughly explored in this study. Utilizing the EXPLO5 (version 6.02) software57, we systematically compared the detonation performance of AEM-DATNBI and CEM-DATNBI (Figure 5h). The results clearly indicated that the detonation velocity and pressure of AEM-DATNBI were significantly superior to those of γ-DATNBI, nevertheless lower than those of β-DATNBI and α-DATNBI. This discrepancy stems from the reduced density of DATNBI following amorphization, as detailed in the Supplementary Fig. 26. For energetic materials, the density metric is not the sole determinant of ultimate application performance. It is noted that amorphous materials can achieve favorable thermoplastic processing properties without reliance on polymeric binders. This characteristic implies that devices ultimately composed of pure energetic substances may surpass or equal the energy density of PBX (polymer-bonded explosives) systems containing inert binders58. Consequently, amorphous materials not only compensate for potential performance limitations arising from density differences but may even achieve superiority in certain aspects. Furthermore, the thermoplastic forming process enables the creation of uniform, dense charge structures. This microstructure shows promise for enhancing detonation performance, as it provides a more stable and efficient pathway for detonation wave propagation, which can contribute to faster and more complete energy release.

Methods
Glass transition and melting temperature analysis
The thermal behavior of all samples was characterized using a NETZSCH DSC 204F1 Phoenix apparatus (NETZSCH-Gerätebau GmbH, Selb, Germany). Precisely weighed samples (~2 mg) in platinum crucibles, with an empty crucible as reference, were subjected to a controlled atmosphere under continuous nitrogen purge to prevent oxidative degradation. A two-step temperature program was employed (Supplementary Fig. 2a). In the first step, samples were heated from room temperature (T ) to T 10 K/min (Upscan 1), where T was maintained above the melting temperature (T ) but below the onset of thermal decomposition (T ). Subsequently, the melt was rapidly quenched to a sub-ambient temperature T₂ at 50 K min⁻¹ to facilitate glass formation. Following this, the quenched material was ramped back up from T₂ to a target temperature T proximal to T at 10 K/min (Upscan 2), with the specific objective of detecting the glass transition temperature (T )via analysis of the characteristic step change in the heat flow profile.

Preparation of AEM-DAATNBI
1,1ʹ-Diamino-4,4ʹ,5,5ʹ-tetranitro-2,2ʹ-biimidazole (DATNBI) was obtained from the Institute of Chemical Materials, China Academy of Engineering Physics. Initially, crystalline DATNBI (10mg) was positioned on a Linkam LTS420 heating stage to its melting point of 236.2 °C. Subsequently, the sample was permitted to melt entirely into a liquid state. The molten sample was rapidly quenched and cooled in liquid nitrogen to yield AEM-DATNBI. The resulting AEM-DATNBI was carefully removed and stored for subsequent use. The sunthesized AEM-DATNBI is transparent bulk material featuring a smooth surface and a homogeneous structure (Figure 2a). Notably, no elaborate workup procedures or specialized experimental equipment were employed during the formation of this glassy material.

Characterization
The morphology of CEM-DATNBI and AEM-DATNBI were analyzed by field-emission scanning electron microscope (SEM), Ultra-55, Carl Zeiss. Samples were observed by Scope.A1 polarizing optical microscope (ZEISS, Germany). Powder X-ray diffraction (PXRD) spectra were collected on Bruker D8, with Cu Kα radiation source (λ = 1.54180 Å). X-ray total scattering data were then collected, with an X-ray generator providing Ag Kα radiation of wavelength 0.55941 Å. Samples were loaded into borosilicate glass capillaries of 0.5 mm (inner) diameter. Data from the samples, empty instrument and empty capillary were collected and processed using the PDFgetX3. The functional groups information of the samples was obtained by an infrared spectrometer (FT-IR, Tensor-27, Bruker, Germany), with the range of 600–4000 cm -1. Ultra-performance liquid chromatography−mass spectrometry (UPLC−MS) measurements were conducted on Thermo Fisher Scientific. The simultaneous differential scanning calorimetry and thermogravimetric (TGA-DSC, 1100L, Mettler-Toledo, Switzerland) analysis the thermoanalytical behaviour of the samples under a nitrogen atmosphere at heating of 5 K/min, 10 K/min, 15 K/min, and 20 K/min. The SAXS data used in this experiment are obtained by Xeuss2.0 small-angle X-ray scattering instrument produced by Xenocs company. For the laser ignition test, 20 mg of samples were radiated using a 10 W, 1064 nm infrared laser (MFSC-10, Maxphotonics) and recorded using a high-speed camera (VLEO410L, Photron). the pressure sensor (PC290) was used collected the pressure evolution with time of samples in a constant-volume vessel (300 mL)59. Safety properties were quantified through standardized impact sensitivity (IS) and friction sensitivity (FS) tests following the Bundesanstalt für Materialforschung (BAM) protocol60. Atomic force microscope (AFM) images were collected on a Bruker (SPA300HV Seiko). The contact angle and surface energy calculation of CEM-DATNBI and AEM-DATNBI were studied via a Kruss Scientific DSA100S model.

Activation energy (E ) calculation
a
The thermal decomposition behaviour of the samples was characterised by simultaneous thermogravimetric-differential scanning calorimetry (TGA-DSC, Mettler Toledo), where the sample mass of 2-3mg was placed in an alumina crucible, and the temperature programmer was set at a constant rate of 10 K/min from 30 ℃ to 500 °C under N atmosphere. Meanwhile the thermal decomposition behaviours of AEM-DATNBI and CEM-DATNBI were detected at different heating rates (5 K/min, 15 K/min, 20 K/min). The Kissinger method was utilized in this study to calculate the activation energy (E ) of thermal decomposition reaction55,56. there is a linear relationship between ln(β/T 2) and 1/T , and the kinetic parameters of thermal decomposition can be calculated by obtaining the T values at different heating rates and equations (1)
ln(β/T 2) = ln(AR/E ) - (E /R)(1/T ) (1)
where β is the heating rate (K/min), T is the thermal decomposition peak temperature (K), A is the pre-exponential factor, R is the ideal gas constant (8.314 J·mol-1·K-1), E is the activation energy (J mol-1).

Simulation and calculation details
To obtain the energetically favorable ground-state molecular geometries, quantum chemical calculations were performed using Gaussian 16W61. Density Functional Theory (DFT) with the APFD hybrid meta-GGA functional and the 6-31G(d) basis set; convergence criteria were maintained at the program defaults to ensure structural stability. The planarity characteristics of the optimized structures were subsequently evaluated through the calculation of two quantitative metrics using the Multiwfn program package (version 3.8)62. The Molecular Planarity Parameter (MPP), a scalar descriptor (ranging 0 to 1) quantifying global deviation from perfect planarity, and the Standard Deviation of Planarity (SDP), reflecting the root-mean-square deviation of atoms from the best-fit molecular plane and thus quantifying out-of-plane distortion. Finally, optimized geometries, computed molecular planes, and atomic deviations were rendered and visualized using the Visual Molecular Dynamics (VMD) software (version 1.9.3)63, enabling intuitive interpretation of planarity features and the spatial distribution of distortions.

The molecular dynamics simulation was carried out using Software Materials Studio. Firstly, 3×3×3 supercell for DATNBI (Supplementary Fig. 27) were constructed according to the unit cells. Then the supercells were optimized and energy-minimized using molecular mechanics (MM). The optimized supercells were relaxed using molecular dynamics (MD) simulations under NVT ensemble (with constant particle number, volume and temperature)64–66 at room temperature 298 K for 10 ps. Then the heating process was performed on each supercell with MD simulations under NPT ensemble (with constant particle number, pressure and temperature) 67 at 1000 K and 1 atm for 250 ps. The used temperature 1000 K is much higher than the melting points of the compounds, so that the melting process can be accelerated; meanwhile, during the simulations, the non-reactive COMPASS forcefield 68,69 was utilized to preclude chemical reactions at this high temperature. The melting cells were equilibrated under NVT ensemble at 1000 K for additional 50 ps. Finally, the supercells were cooled under NPT ensemble at 298 K and 1 atm for 250 ps, in order to obtain equilibrated glassy samples (Supplementary Fig. 28). Hydrogen bonds were characterized using conventional geometric thresholds, applying a donor-acceptor (D–A) distance limit of 3.0 Å and a donor-hydrogen-acceptor (D–H–A) angle threshold of 120°.

The density of the final amorphous supercells were measured, as well as the radial distribution function (RDF) was analyzed for each cell. The RDF gives a measure of the probability that, given the presence of an atom at the origin of an arbitrary reference frame, there will be an atom with its center located in a spherical shell of infinitesimal thickness at a distance, r, from the reference atom. This concept encompasses the principle that an atom at the origin and another at distance r may belong to distinct chemical species α and β, with the corresponding relationship formalized in equation (2)70.
ρg (r) = 1/N [∑Nα ∑Nβ δ(r-r +r)] (2)
where x is the mole fraction of chemical type i, N is the number of atoms of chemical type i, N is the total number of atoms, ρ is the overall number density, and g(r) is the RDF.

Peer review rounds
[{"round": 1, "reviewer_comments": {"reviewer_1": "This work developed a strategy to construct stabilizes amorphous energetic material with self-healing capability by entropy-mediated solidification. The authors utilized a range of experimental tools as well as simulations to characterize the structure and properties of this material. This amorphous energetic material exhibits good structural stability, excellent energy release properties, and low mechanical sensitivity. This unique disordered structure provides important insights into the design of energetic materials. However, some experimental details and explanations are inadequate. I would recommend publication of this paper after some minor revision. Specific points to note are listed below.\n1. In Figure 1, the schematic needs to be improved. Does the abbreviation in the subheading ‘’ in the schematic diagram refer to crystalline or amorphous energetic materials? This is unclear from the schematic.\n2. Page 7, line 173, the authors noted that “which kinetically stabilizes the amorphous phase by impeding molecular reorganization, as evidenced by supporting Fig. S8.” However, the hydrogen bonding network is not labelled in the molecular structure of amorphous-DATNBI in Supporting Fig. S8.\n3. Page 7, line 179, the argument on “with surface cracks healing completely within seconds at 60 °C” by showing figure 3a without quantifying the time for crack healing. This result should be described more specifically.\n4. Page 8, line 189, the authors noted that “As quantified through in situ SAXS analysis showed that the porosity of the amorphous phase was 40.6% lower than that of the crystalline phase”. How was 40.6% calculated? If this is a comparison of porosity at a given temperature, a more elaborate explanation should be added to this result.\n5. In Figure 5e, how did the authors account for intermolecular hydrogen bonding? Suggest that the authors provide details of the relevant molecular dynamics simulations.", "reviewer_2": "This work developed a strategy to construct stabilizes amorphous energetic material with self-healing capability by entropy-mediated solidification. The authors utilized a range of experimental tools as well as simulations to characterize the structure and properties of this material. This amorphous energetic material exhibits good structural stability, excellent energy release properties, and low mechanical sensitivity. This unique disordered structure provides important insights into the design of energetic materials. However; some experimental details and explanations are inadequate. I would recommend publication of this paper after some minor revision. Specific points to note are listed below.", "reviewer_3": "The manuscript is well written and interesting. The studies are well thought of.\nOnly two general concerns\n(1) The focus and proposal as the modified material as energetic material may not be correct.\n(2) Is the behavior is general or very specific to the material alone?\nRecommendation is major revision of manuscript and resubmit\nAdditional note: It is well understood that density is foremost parameter that defines the energetic performance of molecules. One of the basic equation to calculate detonation velocity and detonation pressure, Kamlet-Jacobs equation, show that both detonation velocity (by a factor 1+1.3ρ) and detonation pressure increase (by a factor ρ^2) with density. It is true with its modified equations also. Hence, the energetic performance of AEM-DATNBI is expected to lower than that of CEM-DATNBI. In the manuscript, there is a possible indication of this effect, in Fig 4 (f) the pressure increase show a significant difference between amorphous (AEM-DATNBI) and crystalline (CEM-DATNBI) DATNBI. Also, the lower sensitivity of AEM-DATNBI may be indicating lower performance unless the reason are identified."}, "author_response": "Manuscript: Nature Communications NCOMMS-25-23145\nPoint-by-point response letter\nWe would like to thank the Reviewers for their helpful comments and suggestions. We have\nstudied these comments carefully and have made corrections accordingly in the revised\nmanuscript and supplementary material (with changes marked in red font). Detailed point-by-point\nresponses to the Reviewers’ comments are given below.\nReviewer #1 (Remarks to the Author):\nThis work developed a strategy to construct stabilizes amorphous energetic material with self-\nhealing capability by entropy-mediated solidification. The authors utilized a range of experimental\ntools as well as simulations to characterize the structure and properties of this material. This\namorphous energetic material exhibits good structural stability, excellent energy release properties,\nand low mechanical sensitivity. This unique disordered structure provides important insights into\nthe design of energetic materials. However; some experimental details and explanations are\ninadequate. I would recommend publication of this paper after some minor revision. Specific\npoints to note are listed below.\nResponse: We appreciate your attention to our work and we extend our sincere thanks for your\nvaluable feedback. According to the suggestions, we have thoroughly reviewed the results and\ndiscussion section and addressed the major concerns you have raised point by point. Your\nconstructive suggestion is highly valued, and we have made the necessary revisions to ensure the\nquality of our manuscript. Thank you again for your time and insights. Corresponding revisions\nand point-to-point responses are listed as following:\nComments 1. In Figure 1, the schematic needs to be improved. Does the abbreviation in the\nsubheading in the schematic diagram refer to crystalline or amorphous energetic materials? This\nis unclear from the schematic.\nResponse: We are sorry to the confused content in Fig. 1. A new figure was added in the revised\nmanuscript (Fig. 1). In the newly added Fig. 1, crystalline energetic materials are abbreviated as\nCEM and amorphous energetic materials are abbreviated as AEM.\nFig. 1. Structure, properties and potential applications of amorphous energetic materials.\nComments 2. Page 7, line 173, the authors noted that ''which kinetically stabilizes the amorphous\nphase by impeding molecular reorganization, as evidenced by supporting Fig. S8.\" However; the\nhydrogen bonding network is not labelled in the molecular structure of amorphous-DATNBI in\nSupporting Fig. S8.\nResponse: We thank the reviewer for their careful attention to detail. To address this, we have\nnow modified Supporting Figure S12. In the revised figure: We have clearly marked the hydrogen\nbonds within the amorphous-DATNBI molecular structure using dashed lines (or dotted lines, red\nlines) between the relevant donor and acceptor atoms. And marked the length of the hydrogen\nbond.\nFig. S12. Molecular conformations in different crystalline forms (β-DATNBI (a), α-DATNBI (b),\nγ-DATNBI (c)) and amorphous-DATNBI (d).\nComments 3. Page 7, line 179 the argument on ''with surface cracks healing completely within\nseconds at 60 ℃” by showing figure 3a without quantifying the time for crack healing. This result\nshould be described more specifically.\nResponse: We appreciate the reviewer’s comment highlighting the need for more specific\ntemporal information on crack healing. We acknowledge that the original Figure 3a, while\nillustrative, lacked explicit time markers. To provide more concrete evidence, we have re-\nexamined our in situ optical microscopy records captured at 60°C. We now present a series of\nimages (added to Figure 4a) showing the evolution of a representative surface crack at specific\ntime intervals. These images clearly demonstrate that the crack visible at t=0s undergoes\nsignificant narrowing by t=30s and is completely healed by t=73s. Accordingly, we have revised\nthe text on Page 11, line 265 to state: ‘… with surface cracks healing completely within 73\nseconds at 60 °C, as directly observed by in situ optical microscopy at specific time intervals (Fig.\n4a).”\nFig. 4. Self-healing capability and surface character of AEM-DATNBI. (a) POM records the self-\nhealing process of AEM-DATNBI under heat treatment. Temperature-evolution of SAXS profiles\nof CEM-DATNBI (b) and AEM-DATNBI (c). (d) The porosity of AEM-DATNBI and CEM-\nDATNBI. (e) AFM height images of AEM-DATNBI and CEM-DATNBI. (f) Histogram of AFM\ntip-to-sample adhesion force modified by F2314. (g) Surface free energy of AEM-DATNBI and\nCEM-DATNBI by contact angles tests.\nComments 4. Page 8, line 189, the authors noted that ''As quantified through in situ SAXS\nanalysis showed that the porosity of the amorphous phase was 40.6% lower than that of the\ncrystalline phase”. How was 40.6% calculated? If this is a comparison of porosity at a given\ntemperature, a more elaborate explanation should be added to this result.\nResponse: We thank the reviewer for highlighting the need for methodological clarity. We have\nrevised the manuscript as follows to address this point comprehensively:\nThe porosity comparison is now explicitly based on in situ SAXS data collected during heating\nfrom 30 °C to 110 °C. The \"40.6%\" refers to the total reduction in amorphous porosity relative to\nits initial value at 30 °C (not a direct comparison to crystalline phase). Figure 4d shows porosity\nevolution over the entire temperature range, confirming that the amorphous phase consistently\nexhibits lower porosity than the crystalline phase.\nWe have modified the sentence on Page 8, line 189 to explicitly state the temperature and include\nthe calculation basis. \"Quantitative analysis of in situ SAXS data collected during heating from\n30 °C to 110 °C revealed a total porosity reduction of 40.6% in the amorphous phase, while the\ncrystalline phase showed a smaller decrease of 8.8%. Throughout this temperature range, the\namorphous phase consistently exhibited lower porosity than the crystalline phase, as shown in Fig.\n4d.\"\nWe have added a brief description of the SAXS porosity quantification method to the\nsupplementary information. The added calculations and details are as follows:\nThe SAXS data for the samples are presented in Fig. S16-17. Using Fit-2D software1, the relative\nscattering intensity (I) of the samples can be derived. This relative intensity, combined with the\ns\nincident light intensity (I using equation (1), yields the absolute scattering intensity (I ).\ni) a\nFurthermore, the scattering invariant (Q) is determined via equation (2). Based on the definitions\nof the single electron scattering intensity (I , equation 3) and the electron density (ρ , equation 4),\ne e\nthe volume fraction of pores (equations 5) within the samples can be calculated to assess their\ncharacteristics.\nI\na\n( q ) = (\nI\ns\n( q ) / T\nI\nS\ndi\n−\nt P\nI (\nb\nP\nl v\nq ) / T\nb\n) L\nL\n3\nc\nd\n(1)\nQ = \n\na\n( q ) q 2 d q (2)\ne\n2\n1 c o\n2\ns 2 2 \nI = r\ne\n\n+\n(3)\ne\n= E \nM\nm  6 . 0 2 2  1 0 2 3\n\n (4)\nQ=22I ( − )2 (5)\ne e,a e,b a b\nKey parameters include: the relative scattering intensity of the background (I ); the transmittance\nb\nof the sample (T) and background (T ); sample thickness (d); testing time (t); pixel sizes in\ns b\nhorizontal (P) and vertical (P ) directions; distance from sample to detector (L ); distance from\nl v d\nsample to pixel point (L ); the classical electron radius (r = 2.81 × 10-15 cm); atomic number (E);\nc e\nmass density (ρ ); molar mass (M); sample electron density (ρ ); pore electron density (ρ );\nm e,a e,b\nsample volume fraction (φ ).\na\nReferences\n1. Hammersley, A. FIT2D: a multi-purpose data reduction, analysis and visualization program.\nJournal of Applied Crystallography vol. 49 646–652 (2016).\nComments 5. In Figure 5e how did the authors account for intermolecular hydrogen bonding?\nSuggest that the authors provide details of the relevant molecular dynamics simulations.\nResponse: We thank the reviewer for this important question. The intermolecular hydrogen\nbonding interactions in Figure 5e were explicitly modeled and analyzed. We have added a brief\ndescription intermolecular hydrogen bonding interactions in the revised manuscript (Section\nSimulation and calculation details). \"Hydrogen bonds were identified using standard geometric\ncriteria: a donor-acceptor (D-A) distance cutoff of 3.0 Å and a donor-hydrogen-acceptor (D-H-A)\nangle cutoff of 120°.\"\nReviewer #2 (Remarks to the Author):\nThe present manuscript describes a successful production of a specific energetic material into an\namorphous form. This is a nice result but does not seem significant enough to merit being placed\ninto Nature Communications and would be better suited to the domain specific journal such as\nPropellants Explos. Pyrotech. Thus, though this reviewer finds nothing technically wrong with the\nmanuscript, it also is not fundamentally novel. For example, there is a significant body of work in\nthe pharmaceutical industry to find pathways to making stable amorphous systems. Several groups\nhave looked at the problem in terms of glass-forming ability (cf. for example Baird, J. A.; Van\nEerdenbrugh, B.; Taylor, L. S. A J. Pharm. Sci. 2010, 99, 3787−3806; Nagapudi, K.; Jona, J. Curr.\nBioact. Compd. 2008, 4, 213−224; Yu, L. Adv. Drug Deliv. Rev. 2001, 48, 27−42). Some more\nrecent publications are provided in the references below.\nThe only really novel aspect here is the material itself and the efforts to characterize the impact of\nthe amorphous state on the behaviors of the material. On this score, there are no error bars on the\nnumbers, so it is difficult to judge if they are actually different, e.g., the activation energies are not\nvery different. But the comment is true for most of the numbers given either in tables or in the\nbeautiful Figure 6. One comment is that the authors also don’t comment on the fact that the\namorphous low density material has a combustion velocity that is higher for the amorphous phase\nthan the crystalline phase. Normally, in my understanding, the detonation velocity is greater for\nthe higher density materials, thus the interest of the community in CL-20. In sum, it is this\nreviewer’s recommendation that the manuscript be submitted to a more appropriate venue rather\nthan Nature Communications.\nWe thank the reviewer for the careful reading. According to the suggestions, we have thoroughly\nreviewed the results and discussion section and addressed the major concerns you have raised\npoint by point. Your constructive suggestion is highly valued, and we have made the necessary\nrevisions to ensure the quality of our manuscript. Thank you again for your time and insights.\nCorresponding revisions and point-to-point responses are listed as following:\nComments 1: \" The present manuscript describes a successful production of a specific energetic\nmaterial into an amorphous form. This is a nice result but does not seem significant enough to\nmerit being placed into Nature Communications and would be better suited to the domain specific\njournal such as Propellants Explos. Pyrotech. Thus, though this reviewer finds nothing technically\nwrong with the manuscript, it also is not fundamentally novel. For example, there is a significant\nbody of work in the pharmaceutical industry to find pathways to making stable amorphous\nsystems. Several groups have looked at the problem in terms of glass-forming ability (cf. for\nexample Baird, J. A.; Van Eerdenbrugh, B.; Taylor, L. S. A J. Pharm. Sci. 2010, 99, 3787−3806;\nNagapudi, K.; Jona, J. Curr. Bioact. Compd. 2008, 4, 213−224; Yu, L. Adv. Drug Deliv. Rev. 2001,\n48, 27−42). Some more recent publications are provided in the references below. \"\nResponse: We sincerely thank the reviewer for their insightful comments and for highlighting the\nextensive body of work on amorphous systems in the pharmaceutical field. We agree that clearly\narticulating the fundamental novelty and broader significance of our work in the context of these\nprior studies is crucial. To directly address the reviewer’s valid point and ensure that the unique\nchallenges, novel strategy, and wider implications of our work are unmistakably clear to all\nreaders, we have significantly revised the manuscript, particularly in the Abstract, Introduction,\nand Results & Discussion sections. Below, we respond to each of your comments in detail:\n(1). We added a clearer context and brief descriptions of the methods in the introduction of the\nrevised manuscript. We have reframed the opening sentences of the abstract to explicitly state the\nfundamental challenge of amorphizing rigid organic small molecules, such as energetic materials:\n“Amorphous materials have penetrated various fields of modern technology. However, achieving\namorphous states in rigid organic small molecules remains fundamentally challenged by their\nstrong crystallization tendency, restricting deployment in defence and military domains like\nexplosives design\".\nOur introduction focuses on addressing the fundamental challenge of forming stable amorphous\nstates in rigid organic small molecules. Amorphous materials are critical across various fields due\nto their unique disordered structure—characterized by short-range order but long-range disorder—\nand their superior properties. However, rigid organic small molecules exhibit a strong inherent\ntendency to crystallize and possess small steric hindrance, making the formation of stable\namorphous phases difficult and thereby limiting their practical utility. Current research\npredominantly targets molecules with specific structural features (e.g., long alkyl chains,\npolyaromatic rings, flexible linkers, or particular functional groups), leaving the amorphization of\nstructurally simpler rigid small molecules (such as mono- or bicyclic compounds) comparatively\nunderexplored.\nEnergetic molecules present an ideal model system to address this challenge of amorphizing rigid\nsmall molecules, owing to their inherent high rigidity, high energy density, and tunable weak\nintermolecular interactions (e.g., hydrogen bonding facilitated by nitro or amino groups). Crucially,\nunlike pharmaceutical amorphization, which primarily aims to enhance bioavailability and\nfrequently relies on polymer additives or co-amorphous dispersant, energetic systems require\nstabilization of the amorphous phase without compromising energy density. The strict avoidance\nof exogenous components is therefore essential. This specific application context imposes more\nstringent constraints on the preparation of amorphous organic small molecules.\nTo overcome this core challenge, our study employed structurally well-defined energetic\nmolecular systems. We implemented a functional group engineering strategy, modulating\nmolecular planarity, intermolecular interactions, and steric hindrance. This approach successfully\nyielded a fully amorphous and homogeneous energetic material. We emphasize that this strategy\nestablishes a foundation for developing next-generation energetic materials characterized by stable\nperformance, rich functionality, and flexible processability. Furthermore, it provides a successful\nparadigm for addressing the central challenge of low glass-forming ability inherent to rigid small\nmolecules.\n(2). We recognize that the unique formation mechanism of amorphous DATNBI revealed in this\nstudy holds broad scientific significance and application prospects. Therefore, we have placed\nspecial emphasis on elucidating its innovative aspects. To enhance the clarity and general\napplicability of this core finding, we have expanded the systematic exposition of this mechanism.\nSpecifically, we have expanded the analysis of melt-processed energetic materials across three\nprimary categories: imidazole derivatives, benzene derivatives, and polycyclic compounds (Fig.\nS1), to assess their amorphous phase formation capabilities under a cooling rate of 50 K/min. By\ncorrelating molecular planarity, steric hindrance, and intermolecular interactions with non-\ncrystallization behavior, we explicitly elucidate the rationale of our molecular design strategy.\nThese melt-processed energetic materials encompass three primary categories: imidazole\nderivatives, benzene derivatives, and polycyclic compounds. The powder sample was heated from\nroom temperature (T ) to a temperature (T ) greater than T but less than T . The product is\n0 1 m d\ncooled at a rate of 50 k/min to T . For the Upscan 2 stage, the product was reheated from T to T ,\n2 2 3\nand the glass transition was observed (Fig. S2a).\nFig. S1. The molecular structure of small molecule explosives that can be melt-molded.\nFig. S2. Procedure for the DSC-TGA measurements (a). Thermogravimetric analysis and\nenthalpic responses of the DFTNAN (b), DNAN (c), DNB (d).\nDistinct crystallization exotherms were observed upon cooling for DNB, DNAN, DMDNP (Fig.\nS2c-d, Fig. S3c), indicating their strong tendency to form ordered crystalline phases even under\nfast quenching. In contrast, no crystallization peaks were detected for DFTNAN, DNP, and MTNP\nduring cooling (Fig. S2b, Fig. S3a-b), suggesting the potential formation of metastable\nsupercooled liquids or glasses. Subsequent reheating confirmed that DFTNAN, DNP, and MTNP\nexhibited clear glass transitions (T ), characterized by step changes in heat capacity.\ng\nFig. S3. Thermogravimetric analysis and enthalpic responses of the DNP (a), MTNP (b), DMDNP\n(c).\nQuantitative analysis of molecular planarity parameters revealed the following trend:\nDFTNAN (MPP=0.519) > DNAN (MPP=0.226) > DNB (MPP=0.00) (Fig. S13). We preliminarily\nattribute this to the ether-methyl functional group in DFTNAN disrupting molecular symmetry,\nreducing planarity, and increasing steric hindrance to molecular migration, which collectively\nimpedes ordered crystalline packing. Notably, although DNP lacks significant steric hindrance groups\n(unlike DFTNAN and MTNP) and has a nearly planar structure (molecular planarity parameter\n(MPP): DFTNAN (0.519) > MTNP (0.408) > DNP (0.367)), it formed an amorphous state with a\nmeasurable glass transition temperature (T = -19.57 °C). This observation contradicts\ng\nexpectations that highly planar molecules preferentially undergo ordered packing and\ncrystallization. We propose that this phenomenon originates from DNP simultaneously possessing\nhydrogen-bond donors and acceptors. During amorphization, these functional groups promote\nextensive intermolecular hydrogen-bond network formation. The resultant intermolecular\ninteractions effectively kinetically trap molecules, hindering their reorganization into long-range\nordered lattices while inducing short-range ordered molecular clusters that ultimately stabilize the\namorphous architecture.\nFig. S4. Thermogravimetric analysis and enthalpic responses of the DNTF (a), BTF (b).\nTo investigate whether incorporating additional rigid rings beyond simple functional groups could\nfurther reduce molecular planarity, we examined polycyclic compounds DNTF and BTF (Fig. S4).\nOur analysis reveals that DNTF's three furazan rings, connected by C-C bonds, exhibit structural\nflexibility. Rotation around these C-C bonds generates substantial steric hindrance, causing\nsignificant deviation from ideal planarity. It is evidenced by DNTF's high MPP value of 0.962 (Fig.\nS13). This molecular architecture demonstrates superior flexibility compared to the rigid BTF\nframework. Crucially, melt-quenched amorphous DNTF solid exhibits a glass transition\ntemperature of -17.19°C, confirming successful amorphous phase formation.\nCrucially, for these glass-formers (DNP, DFTNAN, DNTF), cold crystallization exotherms\nappeared shortly after T (< 30 °C) during reheating (Table S1). This behavior unequivocally\ng\ndemonstrates the thermodynamic instability of their amorphous forms, which readily undergo\nstructural relaxation and recrystallize upon warming to near-ambient temperatures. Consequently,\nthese amorphous phases lack the structural stability required for potential applications within\ntypical service temperature ranges (e.g., room temperature to 50°C).\nTable S1. The glass transition temperatures, crystallization temperatures, Molecular Planarity\nParameter (MPP) and Span of Deviation from Plane (SDP) of amorphous explosives\nMolecule Molecular skeleton T (°C) T (°C) MPP SDP\ng c\nDFNAN benzene ring -45.62 -7.82 0.519 2.212\nDNP imidazole -19.57 26.53 0.38 1.559\nMTNP imidazole -18.65 27.30 0.41 2.236\nDNTF dinitrofurazanfuroxan -17.19 24.18 0.962 3.944\nDATNBI bisglyoxaline 59.67 98.26 0.416 1.811\nThe ability of DATNBI to form a stable amorphous state originates from its unique molecular\ndesign. Molecular-level analysis reveals that poor molecular planarity (molecular planarity\nparameter (MPP) > 0.3) is the key initial factor inhibiting crystallization (Fig. S13). Non-planar\nstructures (e.g., the steric hindrance of the methoxy group in DNAN and the rotatable flexible\nfurazan ring in DNTF) effectively increase spatial steric hindrance, weaken intermolecular\ninteractions, reduce attractive forces, and hinder ordered crystal lattice formation. However, as\nshown in Fig. S2-4), the glass transition temperatures (T ) of these amorphous explosives (DNP,\ng\nDFTNAN, MTNP, DNTF) are all significantly below 30 °C, indicating that their amorphous states\nare highly unstable at ambient temperature and prone to recrystallization. The DNP case revealed\ncrucial insights. Despite exhibiting high molecular rigidity, absence of flexible functional groups\n(Fig. S3a), and poor planarity (MPP=0.367, Fig. S13), it successfully forms an amorphous state\nwith a glass transition temperature (T ) of -19.67 °C, significantly higher than that of DFTNAN ( -\ng\n46.48 °C). This contrast strongly suggests that the formation of an intermolecular hydrogen-\nbonding network (via hydrogen bond donors/acceptors) is crucial for enhancing amorphous\nstability, effectively strengthening intermolecular interactions and suppressing ordered\nrearrangement. Building on this insight, the design strategy for DATNBI focuses on synergistic\neffects. Initially, spatial hindrance is employed to reduce planarity (e.g., through backbone\nmodification and the introduction of flexibility), providing the foundation for amorphous\nformation. Subsequently, the intermolecular hydrogen-bonding network is reinforced. DATNBI\nwas selected as a model molecule because it contains dual amino groups (strong hydrogen bond\ndonors) and dual nitro groups (strong hydrogen bond acceptors). This design aims to significantly\nincrease the density of hydrogen bond donors/acceptors, promoting the formation of a stronger\nintermolecular hydrogen-bonding network. Furthermore, the inherent non-planarity of the\nDATNBI structure, coupled with the synergistic effect of its bis-imidazole framework, increases\nmolecular conformational complexity and spatial hindrance (Fig. S15). This further reduces\nmolecular motional freedom, contributing to the maintenance of the disordered structure.\nFig. S13. The molecular planarity parameter (MPP) and span of deviation from plane (SDP) are\nused to quantify planar characteristics. Smaller values indicate greater planarity, with the\nmolecular structure being closer to a perfectly planar configuration. Atoms above the fitting plane\nare shown in red, those below in blue, and atoms on the fitting plane are depicted in white.\nFig. S15. Planar structures, and molecular planarity parameter (MPP) of (a) β-DATNBI, (b) α-\nDATNBI, and (c) γ-DATNBI.\nIn summary, we establish a direct correlation between molecular structural features – specifically\nthe non-planar backbone and dual-NH₂/dual-NO₂ groups that reinforce hydrogen-bond networks –\nand the amorphous formation process (thermally induced lattice disordering/crystallization\ninhibition), alongside stability enhancement mechanisms (steric hindrance suppressing\nrearrangement and hydrogen-bond networks strengthening intermolecular interactions). This\nintegrated analysis elucidates the multi-scale synergistic mechanism enabling DATNBI to achieve\nexceptional amorphous stability. In the revised manuscript, we have systematically reorganized\ncontent regarding amorphous energetic material preparation and formation mechanisms to\nemphasize this conceptual framework. We hope to provide a process framework suitable for\namorphization of rigid small molecules, which is applicable across disciplines in the fields of\nphotonics and semiconductors.\nComments 2: \"The only really novel aspect here is the material itself and the efforts to\ncharacterize the impact of the amorphous state on the behaviors of the material. On this score,\nthere are no error bars on the numbers, so it is difficult to judge if they are actually different, e.g.,\nthe activation energies are not very different.\"\nResponse: We appreciate your insightful point, which has helped us to improve the quality of our\nmanuscript. We agree entirely that the absence of error bars or other measures of uncertainty\nmakes it challenging to assess the statistical significance of apparent differences in the data. To\naddress this point rigorously, we have undertaken the following actions:\nFor data derived from repeated independent experiments, we have added error bars to relevant\ndata points in Fig.4g and Fig.5d, based on n = 3 replicates. For the activation energy, we have\ncalculated and given the fit (R2) of the linear regression model, the R2 values are now presented in\nsupplementary information (Table S2) and discussed in the revised manuscript on page 10, lines\n239 \"It can be clearly seen that all fitted lines exhibit a good linear relationship (R2 > 0.96).\"\nFig. 4g. Surface free energy of AEM-DATNBI and CEM-DATNBI by contact angles tests.\nFig. 5d. IS and FS of AEM-DATNBI and CEM-DATNBI\n)m/Nm(\nygrene\necafrus\n6\n5\n4\n3\n2\n1\n0\n0\n0\n0\n0\n0\ns u\nE\nr fa\nM\nc\n-\ne\nD\ne\nA\nn e\nT\nr g\nN\ny\nB I\nd is p e\nC\nr s\nE\nio\nM\nn\n- D A\np o\nT\nla\nN\nr itie\nB I\ns\nAEM-DATNB\nγ\nI -DATNBI α-DATNBI β-DATNBI\n)J(\nSI\n1\n1\n1\n1\n6\n4\n2\n0\n8\n6\n4\n2\nF\nSS\n3\n2\n2\n1\n1\n5\n0\n0\n5\n0\n5\n0\n0\n0\n0\n0\n0\n0\n)N(\nSF\nTable S2. Thermal decomposition temperature by DSC and calculated Kissinger Ea of raw\nmaterials and relevant energetic composites.\nSamples β (℃) T (℃) 1000/T (K-1) In(β/T2) E (kJ·mol-1) R2\np α\n5 234.92 1.96824 -10.85179\nAEM-DATNBI 10 247.17 1.92190 -10.20629\n122.94 0.998\n(T ) 15 253.50 1.89879 -9.82502\nP1\n20 258.67 1.88034 -9.55687\n5 250.92 1.90815 -10.9138\nAEM-DATNBI 10 263.00 1.86515 -10.26624\n152.35 0.961\n(T ) 15 265.75 1.85563 -9.87101\nP2\n20 271.67 1.83548 -9.60517\n5 252.50 1.90241 -10.91983\nCEM-DATNBI 10 263.17 1.86457 -10.26687\n145.91 0.993\n(T ) 15 270.25 1.84026 -9.88764\nP1\n20 273.33 1.82988 -9.61127\n5 260.50 1.87389 -10.95004\nCEM-DATNBI 10 271.83 1.83492 -10.29892\n144.35 0.988\n(T ) 15 279.25 1.81028 -9.92049\nP2\n20 282.00 1.80131 -9.64274\nComments 3: \" But the comment is true for most of the numbers given either in tables or in the\nbeautiful Figure 6. One comment is that the authors also don’t comment on the fact that the\namorphous low density material has a combustion velocity that is higher for the amorphous phase\nthan the crystalline phase. Normally, in my understanding, the detonation velocity is greater for\nthe higher density materials, thus the interest of the community in CL-20. \"\nResponse: We sincerely thank the reviewer for raising this important point regarding the\ncombustion velocities and densities reported in the manuscript, particularly in Figure 6 and the\ntables.\nAs highlighted in the revised manuscript, the primary focus and novelty of our work lie in\nelucidating the fundamental mechanisms governing the formation of amorphous energetic materials.\nTo sharpen this focus and enhance the clarity of our core contribution, we have removed\nthe \"Structure and performance relationships\" section, including those originally summarized in\nFigure 6 and the accompanying tables. This restructuring ensures the main text concentrates on the\ninsights into amorphous phase formation.\nThe reviewer correctly notes the observation that the amorphous, lower-density AEM-DATNBI\nexhibits a higher combustion velocity (56.5 mg/s) compared to its crystalline counterpart (45.2\nmg/s), representing a 25% increase. We agree that this finding merits explicit discussion, which\nwe have now incorporated into the revised manuscript (Page 14, Line 35). In this added discussion,\nwe explain that the enhanced combustion rate in the amorphous phase is mechanistically linked to\na significant reduction in the thermal decomposition activation energy (ΔEa = 122.94 kJ·mol⁻¹).\nMolecular-scale disorder in the amorphous state effectively eliminates the energy barrier\nassociated with disrupting the long-range crystalline lattice order. This facilitates easier initiation\nof decomposition reactions at the molecular level, thereby accelerating the overall combustion\nkinetics. This is corroborated by the observed increase in peak pressure during constant-volume\ncombustion tests.\nIt may be because the description in Figure 6 confuses readers, that is, “the amorphous low density\nmaterial has a combustion velocity that is higher for the amorphous phase than the crystalline\nphase. Normally, in my understanding, the detonation velocity is greater for the higher density\nmaterials,”. According to the Kamlet-Jacobs equations (Equations (1) and (2))1, demonstrate that\nboth detonation velocity and pressure increase with density. This explains why the detonation\nvelocity and pressure of AEM-DATNBI (density: 1.89 g/cm3, detonation velocity: 8840 m/s) in\nthe manuscript are lower than those of CEM-DATNBI (β-DATNBI, density: 1.95 g/cm3,\ndetonation velocity: 9129 m/s).\n𝑃 =𝐾𝜌2∅,𝐾 =15.58,∅=𝑁𝑀1/2𝑄1/2 (1)\n0\n1\n𝐷 =𝐴∅2(1+𝐵𝜌\n0\n),𝐴=1.01,𝐵 =1.30 (2)\nwhere P is expressed in kilobars, D in millimeters per microsecond, N in moles of gas per gram of\nexplosive, M in grams of gas per mole of gas, Q in calories per gram, and Po in grams per cubic\ncentimeter.\nThe burning rate and combustion pressure are determined by multiple factors including chemical\nkinetics and thermodynamics. While the influence of material density on combustion behavior\ncannot be ruled out. For instance, studies on cellulosic materials show increased density leads to\nprolonged burning times2–4. Therefore, the burning velocity and detonation velocity of energetic\nmaterials are completely different concepts. While the manuscript reports that AEM-DATNBI\n(density: 1.87 g/cm3) burns faster than γ-DATNBI (density: 1.79 g/cm3). This higher burning rate\nis attributed to the amorphous structure eliminating the crystalline lattice energy barrier (resulting\nin a 15.7% reduction in activation energy) as well as its uniform and isotropic microstructure,\nwhich likely promotes more uniform flame spread across the material's surface.\nReferences:\n1. Naminosuke, K. Combustion of explosives. in Propellants and Explosives 257–272 (John\nWiley & Sons, Ltd, 2006). doi:https://doi.org/10.1002/9783527610105.ch9.\n2. Mostashari, S. M., Mostashari, S. Z. & Mostashari, S. M. The effect of weight content or\ndensity on the burning behavior of some cellulosic specimens. Polym.-Plast. Technol. Eng. 47,\n819–823 (2008).\n3. Mao, Y. et al. Rapid assembly of multilayer nanostructured FG/Al energetic materials to obtain\nhigh combustion reactivity. Chem. Eng. J. 473, 145302 (2023).\n4. Wang, J. et al. Synergistic reaction of spherical B/Al/PTFE fuel prepared by confinement-\nemulsion-templated strategy to achieve high energy and reactivity. Combust. Flame 259,\n113113 (2024).\nReviewer #3 (Remarks to the Author):\nThe manuscript is well written and interesting. The studies are well thought of.\nOnly two general concerns\nComments 1. The focus and proposal as the modified material as energetic material may not be\ncorrect.\nResponse: We sincerely appreciate the insightful critique from the reviewer. This comment has\nfundamentally reshaped the scientific narrative in our study. We fully agree that the initial research\nfocus was inconsistent with the deeper scientific discovery potential of our work. To address this,\nwe have significantly revised the manuscript, particularly in the Abstract, Introduction, and\nResults & Discussion sections. Our introduction focuses on addressing the fundamental challenge\nof forming stable amorphous states in rigid organic small molecules. We implemented a functional\ngroup engineering strategy, strategically modulating molecular planarity, intermolecular\ninteractions, and steric hindrance. This approach successfully yielded a fully amorphous and\nhomogeneous energetic material. We emphasize that this strategy establishes a foundation for\ndeveloping next-generation energetic materials characterized by stable performance, rich\nfunctionality, and flexible processability. Furthermore, it provides a successful paradigm for\naddressing the central challenge of low glass-forming ability inherent to rigid small molecules.\nFig. S1. The molecular structure of small molecule explosives that can be melt-molded.\nSpecifically, we have enhanced the mechanistic analysis by evaluating the ability of three types of\nmelt-processed energetic materials (imidazole derivatives, benzene derivatives, and polycyclic\ncompounds) to form amorphous phases at a cooling rate of 50 K/min, as shown in Fig. S1. The\nanalysis revealed that poor molecular planarity (molecular planarity parameter, MPP > 0.3), steric\nhindrance, and intermolecular interactions are key factors inhibiting crystallization and promoting\nthe amorphous state, as demonstrated by DNAN, DNTF, and MTNP (Fig. S2-4). However, a\ncritical limitation emerged: the glass transition temperatures (T ) of these amorphous materials\ng\n(e.g., DFTNAN, MTNP, DNTF) are all significantly below 30 °C, indicating their high instability\nat ambient temperature and susceptibility to cold crystallization upon reheating (Table S1).\nFig. S2. Procedure for the DSC-TGA measurements (a). For the Upscan 1 stage, the powder\nsample was heated from room temperature (T ) to a temperature (T ) greater than T but less than\n0 1 m\nT . The product is cooled at a rate of 50k/min to T . For the Upscan 2 stage, the product was\nd 2\nreheated from T to T , and the glass transition was observed. Thermogravimetric analysis and\n2 3\nenthalpic responses of the DFTNAN (b), DNAN (c), DNB (d).\nFig. S3. Thermogravimetric analysis and enthalpic responses of the DNP (a), MTNP (b), DMDNP\n(c).\nFig. S4. Thermogravimetric analysis and enthalpic responses of the DNTF (a), BTF (b).\nTable S1. The glass transition temperatures, crystallization temperatures, Molecular Planarity\nParameter (MPP) and Span of Deviation from Plane (SDP) of amorphous explosives\nMolecule Molecular skeleton T (°C) T (°C) MPP SDP\ng c\nDFNAN benzene ring -45.62 -7.82 0.519 2.212\nDNP imidazole -19.57 26.53 0.38 1.559\nMTNP imidazole -18.65 27.30 0.41 2.236\nDNTF dinitrofurazanfuroxan -17.19 24.18 0.962 3.944\nDATNBI bisglyoxaline 59.67 98.26 0.416 1.811\nThe DNP case revealed crucial insights. Despite exhibiting high molecular rigidity, absence of\nflexible functional groups (Fig. S3a), and poor planarity (MPP=0.367, Fig. S13), it successfully\nforms an amorphous state with a glass transition temperature (T ) of -19.67 °C, significantly\ng\nhigher than that of DFTNAN ( -46.48 °C). This contrast strongly suggests that intermolecular\nhydrogen-bond (H-bond) networks (formed via H-bond donors/acceptors) are essential for\nenhancing amorphous stability, effectively strengthening intermolecular interactions and\nsuppressing ordered rearrangement.\nFig. S13. The molecular planarity parameter (MPP) and span of deviation from plane (SDP) are\nused to quantify planar characteristics. Smaller values indicate greater planarity, with the\nmolecular structure being closer to a perfectly planar configuration. Atoms above the fitting plane\nare shown in red, those below in blue, and atoms on the fitting plane are depicted in white.\nBuilding on this, the DATNBI design strategy integrates a synergistic dual approach: Firstly,\nspatial hindrance (e.g., its bis-imidazole backbone and inherent non-planarity) is utilized to reduce\nmolecular planarity (MPP > 0.3), establishing the foundation for amorphous formation. Secondly,\nthe intermolecular H-bond network is significantly reinforced. The DATNBI molecule\nincorporates strong H-bond donors (dual -NH₂ groups) and strong acceptors (dual -NO₂ groups),\nmarkedly increasing H-bond density. The synergistic interplay between this non-planar molecular\nscaffold and the dense H-bond network simultaneously increases molecular conformational\ncomplexity and steric hindrance to restrict molecular motional freedom, while stabilizing the\ndisordered structure through intermolecular H-bond interactions. This synergy collectively enables\nexceptional amorphous stability in DATNBI.\nIn summary, we establish a direct correlation between molecular structural features—specifically\nthe non-planar backbone and the dual-NH₂/dual-NO₂ groups reinforcing H-bond networks—and\nboth the amorphous formation process (thermally induced lattice disordering/crystallization\ninhibition) and the stability enhancement mechanisms (steric hindrance suppressing rearrangement\nand H-bond networks strengthening intermolecular interactions). This elucidates the multi-scale\nsynergistic mechanism underlying the exceptional amorphous stability of DATNBI. The core\nsynergistic principles identified are: (i) Molecular non-planarity (MPP > 0.3) suppresses\ncrystallization through steric disruption, and (ii) Intermolecular H-bond networks critically\nenhance kinetic stability. This framework provides a strategy for the amorphization of rigid small\nmolecules, applicable across disciplines including energetic materials, optoelectronics, and\nsemiconductor devices, as detailed in the revised manuscript. all changes highlighted in red text\nfor ease of review.\nComments 2. Is the behavior is general or very specific to the material alone?\nResponse: We sincerely appreciate this critical question, which prompted us to rigorously\ndemonstrate the generality of the preparation and performance of amorphous DATNB. To directly\naddress this question, we have fundamentally reframed the focus of our study from a material-\nspecific case to a general strategy for amorphous state design in rigid organic small molecules.\nSpecifically, we revised the Abstract and Introduction to explicitly position our work as a\nfunctional-group-engineering approach. The Abstract now states: \"Based on steric hindrance and\nintermolecular interaction strategies, we overcome the inherent challenge of amorphous phase\nformation in organic small molecules\". In the Introduction, we added a dedicated section outlining\nthe general challenge of rigid small-molecule amorphization: \"Rigid organic small molecules face\ninherent crystallization barriers due to strong ordering tendencies and weak intermolecular\ninteractions, creating a fundamental challenge for achieving stable amorphous states—\nparticularly in low-MW monocyclic/bicyclic systems. Explosive molecules serve as an ideal model\nto address this gap, leveraging their tunable functional groups (e.g., nitro/amino H-bonding) for\namorphization.\" This modification emphasizes the broader challenge of achieving stable\namorphous states in crystallization-prone rigid frameworks. Crucially, we provide comparative\nexperimental evidence in the Results section (Supplementary Fig. 2), demonstrating that our\nstrategy successfully enables amorphous phase formation in multiple rigid small molecules\nbeyond DATNBI—including DNP, MTNP, DFTNAN, and DNTF—through tailored functional-\ngroup modifications (e.g., steric hindrance in DNAN, hydrogen-bond networks in DNP). In the\nMechanism section, we further identify general design rules: non-planar geometry (MPP > 0.3)\nsuppresses crystallization, while dense N–H···O–N hydrogen-bond networks kinetically impede\nreorganization, explaining why bifunctional DATNBI outperforms monofunctional analogues like\nDNP (Fig. 2). We explicitly state that these mechanisms are theoretically applicable to other\nmolecular systems, supported by our successful preparation of additional rigid amorphous small\nmolecules (results to be published separately). All changes are highlighted in red text (Introduction,\nAbstract, and Result) and supported by new data (Supplementary Figs. S1-S4, S13).\nRecommendation is major revision of manuscript and resubmit\nAdditional note: It is well understood that density is foremost parameter that defines the energetic\nperformance of molecules. One of the basic equation to calculate detonation velocity and\ndetonation pressure, Kamlet-Jacobs equation, show that both detonation velocity (by a factor 1 +\n1.3p) and detonation pressure increase (by a factor p^2) with density. It is true with its modified\nequations also. Hence, the energetic performance of AEM-DATNBI is expected to lower than that\nof CEM-DATNBI.\nIn the manuscript, there is a possible indication of this effect, in Fig 4 (f) the pressure increase\nshow a significant difference between amorphous (AEM-DATNBI) and crystalline (CEM-\nDATNBI) DATNBI. Also, the lower sensitivity of AEM-DATNBI may be indicating lower\nperformance unless the reason are identified.\nResponse: We sincerely appreciate the reviewer’s insightful comment regarding the critical role\nof density in energetic performance. We fully agree that density (ρ) is a primary determinant of\ndetonation velocity (D) and pressure (P) as described by the Kamlet-Jacobs equation (𝐷∝1+1.3𝜌,\n𝑃∝𝜌2). To clarify the apparent contradiction in our results, we emphasize that the lower density of\namorphous AEM-DATNBI would indeed reduce its detonation performance (consistent with the\ndensity-dependent relationships for velocity/pressure in the Kamlet-Jacobs equations). However,\nFig. 4f measures combustion pressure rather than detonation pressure. The observed higher\ncombustion pressure in AEM-DATNBI arises from its amorphous structure enables near-total\nmass conversion to gaseous products (97.4% mass loss vs. 77.3% for crystalline β-DATNBI, Fig.\n5b). Crucially, while high energy density often correlates with high sensitivity in crystalline\nexplosives (eg. CL-201), amorphization simultaneously enhances safety and combustion efficiency:\nAEM-DATNBI achieves a 57% reduction in friction sensitivity and 150% increase in impact\ntolerance (Fig. 4d-e) while improving combustion pressure. This aligns with advanced strategies\n(e.g., crystal morphology engineering, co-crystallization2-4) that decouple the energy-sensitivity\ntrade-off. At the same time, it demonstrated how amorphous engineering can play a unique role in\nbalancing reaction integrity and safety performance, establishing a new paradigm for next-\ngeneration energetic materials.\nFig. 5. Safety and Energy Release Characteristics. DSC (a) and TG (b) curves of crystalline and\nAEM-DATNBI. (c) dependence of ln(β/T 2) on 1/T for AEM-DATNBI and CEM-DATNBI.\np p\nIS and FS of AEM-DATNBI and CEM-DATNBI. (e) Flame combustion images. (f) Pressure\nevolution by a constant volume combustion. (g) Pressurization rate and Max pressures of CEM-\nDATNBI and AEM-DATNBI. (h) Detonation velocity and pressure of AEM-DATNBI and CEM-\nDATNBI.\nReferences:\n1. Song, X., Huang, Q., Jin, B. & Peng, R. Fabrication and characterization of CL-20/PEI/GO\ncomposites with enhanced thermal stability and desensitization via electrostatic self-assembly.\nAppl. Surf. Sci. 558, 149933 (2021).\n2. Tariq, Q.-N. et al. Hydrogen-bonded self-assembly of purine with picric acid: super heat-\nresistant and insensitive explosives. Chem. Eng. J. 505, 159133 (2025).\n3. Li, J. et al. Tri-explosophoric groups driven fused energetic heterocycles featuring superior\nenergetic and safety performances outperforms HMX. Nat. Commun. 13, 5697 (2022).\n4. Bennion, J. C. & Matzger, A. J. Development and Evolution of Energetic Cocrystals. Acc.\nChem. Res. 54, 1699–1710 (2021).\nResponse to Reviewers' Comments\nWe sincerely appreciate the editors and reviewers for their time and valuable comments on\nour manuscript. We are delighted that the reviewers found our previous revisions have\nsubstantially improved the manuscript. Following the remaining comments and editorial\nsuggestions, we have conducted comprehensive revisions to fully address all concerns. The\npoint-by-point responses are detailed below.\nReviewer #1 (Remarks to the Author):\nI recommend the publication of this manuscript in its current form.\nResponse: Thank you for reviewing our manuscript and for your high regard for our research. We\nare most gratified that you consider this paper acceptable for publication ‘in its current form’ (‘I\nrecommend the publication of this manuscript in its current form’). Once again, we extend our\nsincere gratitude for your valuable time and encouragement.\nReviewer #3 (Remarks on response to Reviwer 2)\n(1) I do agree with the reviewer's comment that \" Thus, though this reviewer finds nothing\ntechnically wrong with the manuscript, it also is not fundamentally novel\". It can be verified by\nthe references provided by the reviewer.\nResponse: We sincerely thank the reviewer for this critical comment, which allows us to better\narticulate the fundamental novelty of our work.\nAlthough amorphous as a material state has been applied in multiple fields such as\npharmaceuticals, it is not an innovative concept in itself. However, its introduction into the field of\nenergetic materials represents a fundamental breakthrough. This integration is not a simple\ntechnology transplant but rather a complete subversion of the long-standing paradigm in\nexplosives research, which has traditionally relied on crystalline structures. It has created an\nentirely new material foundation of “amorphous energetic materials,” thereby opening an\nunprecedented research direction. This breakthrough has pioneered an unprecedented research\ndirection, accelerating transformative advancements in explosive material development,\nmanufacturing processes, and performance enhancement, thereby opening new avenues for\nexploration and innovation in the field of explosives. This manuscript successfully achieves the\nstabilization and preparation of such high-energy rigid organic small molecules. With the unique\namorphous structure obtained, the material not only effectively suppresses hot spot formation and\nsignificantly enhances safety but also simultaneously accelerates energy release, enabling faster\ncombustion and more complete decomposition. With a glass transition temperature of 59.67°C,\nthis material provides an ideal thermoplastic window for processing, laying the foundation for\nfuture research on binderless forming of energetic materials. It not only simplifies manufacturing\nprocesses but also avoids dilution by inert components, theoretically unlocking immense potential\nfor higher energy density in amorphous energetic materials. Thus, the emergence of amorphous\nenergetic materials pioneers an entirely new, unexplored research frontier in explosives science.\nIts significance extends far beyond the discovery of a novel material, representing a paradigm shift\nin research and a transformative future for the industry.\nRegarding the references cited by the reviewers, we have conducted a detailed comparative\nanalysis. We contend that our work exhibits significant distinctions from these distinguished\nstudies. As noted in the references provided by the reviewers1, high molecular weight, structurally\ncomplex and flexible organic molecules, their abundant functional groups and conformational\ndiversity, which facilitate the formation of amorphous states. In contrast, we concentrate on rigid\norganic small molecules (typically comprising single or minimal ring systems substituted with\nfunctional groups such as –NO₂ or –NH₂). Such molecules are widely recognized in the literature\nas systems that are extremely difficult to form and stabilize in an amorphous state due to strong\nintermolecular interactions and restricted conformational flexibility4. Therefore, this study directly\naddresses the challenge of preparing amorphous states from rigid organic small molecules and\ntackles the scientific problem of synthesizing amorphous energetic materials. Methodologically,\nthe pharmaceutical field employs solid dispersion technology for amorphization5-6, aiming to\neffectively enhance the solubility and biocompatibility of poorly soluble components. However,\nits characteristic of low drug loading capacity limits its application in the field of energetic\nmaterials. The reason lies in the fact that energetic materials must strictly limit the proportion of\npolymeric excipients to ensure their destructive effectiveness. This requirement further increases\nthe difficulty of manufacturing amorphous energetic materials. Instead, we selected a highly\nchallenging molecular system, expanded the application of amorphous materials into new domains,\nand revealed a series of novel performance characteristics.\nIn response to the valuable comments from the reviewers, we have carefully revised the abstract\nand introduction sections of the manuscript. This revision further clarifies the core scientific\nquestions addressed in this study while more prominently highlighting the distinctions between\nour work and existing research, as well as the unique innovative value of our contributions.\n1. Zhao, X. et al. Prediction of the synergistic glass transition temperature of coamorphous\nmolecular glasses using activity coefficient models. Mol. Pharmaceutics 18, 3439–3451 (2021).\n2. Cheng, S. & McKenna, G. B. Isothermal crystallization and time–temperature transformation\nof amorphous nifedipine: a case of polymorphism formation and conversion. Mol. Pharmaceutics\n18, 2786–2802 (2021).\n3. Bhardwaj, S. P. et al. Correlation between molecular mobility and physical stability of\namorphous itraconazole. Mol. Pharmaceutics 10, 694–700 (2013).\n4. Zhou, D., Schmitt, E. A., Law, D., Brackemeyer, P. J. & Zhang, G. G. Z. Assessing Physical\nStability Risk Using the Amorphous Classification System (ACS) Based on Simple Thermal\nAnalysis. Mol. Pharmaceutics 16, 2742–2754 (2019).\n5. Lalge, R., Kumar, N. S. K. & Suryanarayanan, R. Understanding the effect of nucleation in\namorphous solid dispersions through time–temperature transformation. Mol. Pharmaceutics 20,\n4196–4209 (2023).\n6. Nagapudi, K. & Jona, J. Amorphous active pharmaceutical ingredients in preclinical studies:\npreparation, characterization, and formulation. Curr. Bioact. Compd. 4, 213–224 (2008).\n(2) Thus the novelty remains with the materials used and the application area 'high energy\nmaterials'.\nResponse: We thank the reviewer for this positive comment regarding the novelty of our work\nlying in the materials and their application in high-energy materials. In response to this point, we\nhave revised the manuscript to focus on this core aspect. Specifically, as suggested, we have now\nstrengthened the Introduction and Abstract to unequivocally highlight our amorphous energetic\nmaterial as a novel functional material system. The relevant changes can be found on the revised\nmanuscript.\n(3) However, the quality and standard of reported manuscripts (and the characterisation\ntechniques) used are not comparable with that of the submitted manuscripts, making the submitted\nmanuscript a definitely superior one.\nResponse: We sincerely thank the reviewer for this generous assessment and for recognizing the\nrigorous standards we have strived to uphold in this study. Our research has successfully achieved\na stable amorphous state for rigid small molecules by modulating molecular planarity, steric\nhindrance, and intermolecular interactions (hydrogen bonding networks), thereby actively\nsuppressing the crystallization process. Furthermore, we have elucidated the critical role of this\ndisordered structure in determining material properties.\n(4) The real application of this method/materials as energetic material is doubtful, (I too have\ncommented that in my review) because of the lower density exhibited by amorphous materials.\nResponse: We are most grateful for your profound and constructive comments. The point you\nraised concerning the impact of lower density in amorphous materials upon their application\npotential is indeed a crucial issue within our research work. We fully concur that density\nconstitutes one of the core parameters for energetic materials. However, we think that the overall\nperformance and applicability of energetic material are determined by a balance of multiple\nproperties, and our work demonstrates that amorphous DATNBI offers a uniquely favorable\nbalance that can be highly advantageous for specific applications. In practical applications,\nconventional crystalline energetic materials (such as TATB and RDX) exhibit brittleness, making\nit difficult to meet the mechanical and structural requirements of weapon components through\ndirect pressing alone. Consequently, polymer bonded explosives (PBX) were developed and\nwidely adopted for manufacturing weapon parts. This technology involves dispersing high-energy\nexplosive particles within a polymeric binder matrix, thereby retaining high energy content while\nachieving excellent processability and mechanical integrity1-2. However, since the binder itself\neither does not participate or only minimally contributes to energy release, it reduces the energetic\ndensity of the system, thereby diminishing both detonation velocity and pressure3. Thus, under\nidentical conditions of high-energy component content, PBX typically demonstrates lower density,\ndetonation velocity, and pressure compared to its pure crystalline form (Table 1). In contrast, the\namorphous energetic materials prepared in this study exhibit exceptional thermoplastic\nprocessability owing to their unique glass transition characteristics, enabling the formation of\ncharges composed entirely of pure energetic components without relying on any binders. This\nimplies that although the density of the amorphous material may be lower, its charge density\nequals its material density. As demonstrated by experimental data and reference (Table 1), typical\nPBX charge densities (~1.8 g/cm³) are comparable to the density of our amorphous DATNBI\nmaterial (~1.89 g/cm³), with detonation velocities and pressures reaching 8,840 m/s and 34 GPa,\nrespectively—values that are either at the same magnitude or even more advantageous for the\nlatter. Therefore, in the final charge configuration, amorphous materials comprising 100%\nenergetic components hold promise for surpassing traditional binder-containing PBX systems in\noverall performance.\nTable 1. Explosive formulation data.\nModel number ρa (g/cm3) Vb (m/s) Explosive (wt%) Binder (wt%) Source\nAEM-DATNBI 1.89 8840 DATNBI(100 %) -- This work\nHMX 1.89 9110 HMX(100 %) -- 4\nEstane (2.5%)\nPBX 9501 1.83 8790 HMX(95 %) BDNPA/BDNPF 5\n(2.5%)\nNC (3%), CEF\nPBX 9404 1.85 8802 HMX(94 %) 4\n(3%)\nViton VTR-5883\nPBX 9012 1.84 8590 HMX(90 %) 6\n(10%)\nPBX 9011 1.77 8500 HMX(90 %) Estane 5703 (10%) 4\na Explosive density. b Detonation velocity.\n1. Talawar, M. B., Jangid, S. K., Nath, T., Sinha, R. K. & Asthana, S. N. New directions in the\nscience and technology of advanced sheet explosive formulations and the key energetic materials\nused in the processing of sheet explosives: emerging trends. J. Hazard. Mater. 300, 307–321\n(2015).\n2. Sun, H., Fan, X., Zhan, M., Guo, J. & Zhang, J. Mechanism of uneven densification in PBX\ncompression molding. Int. J. Mech. Sci. 282, 109683 (2024).\n3. He, Z. et al. Effect of 2,4,6‐triamino‐3,5‐dinitropyridine‐1‐oxide on the properties of\n1,3,5‐trinitro‐1,3,5‐triazinane‐based PBX explosives. Propellants, Explos., Pyrotech. 46, 530–536\n(2021).\n4. T.R. Gibbs, A. Popolato, LASL explosive property data, University of California Press, 1980.\n5. Chiquete, C., Short, M., Voelkel, S. J., Anderson, E. K. & Jackson, S. I. Detonation shock\ndynamics modeling and calibration of the HMX-based conventional high explosive PBX 9501\nwith application to the two-dimensional circular arc geometry. Combust. Flame 222, 213–232\n(2020).\n6. Anderson, E. K., Chiquete, C., Jackson, S. I., Chicas, R. I. & Short, M. The comparative\neffect of HMX content on the detonation performance characterization of PBX 9012 and PBX\n9501 high explosives. Combust. Flame 230, 111415 (2021).\nReviewer #3 (Remarks to the Author):\nThe authors have thoroughly revised the manuscript, and its overall perspective is now acceptable.\nHowever, the following points must be addressed before it can be considered for publication.\n1. The focus of the abstract and introduction is too vague. Introduction needs to be refined\nextensively and made technically sound.\nResponse: We sincerely appreciate your review of our manuscript and the valuable feedback you\nprovided. Your observation that the abstract and introduction sections were “The focus of the\nabstract and introduction is too vague.” is very insightful and crucial for improving the\nmanuscript's quality. We have thoroughly rewritten and substantially revised these sections based\non your suggestions. The abstract elucidates the core challenge that rigid organic small molecules\nface in forming stable amorphous phases due to their strong crystallisation tendency, particularly\nwithin the field of energetic materials where high energy density must be maintained. The revised\nversion systematically outlines strategies for achieving structural stability through steric hindrance\nand intermolecular interactions. It reveals the synergistic stabilisation mechanism involving non-\nplanar configurations and hydrogen-bond networks. It summarises improvements in material\nmaterial\nsafety, combustion behaviour, and decomposition performance. The introduction commences with\nthe general concept of amorphous materials, focusing on the specific challenges faced by ‘rigid\norganic small molecules’ and “energetic materials”. It emphasises the demand within this field for\npure-phase, stable amorphous energetic compounds, highlighting the limitations of traditional\nexogenous stabilisation strategies in reducing energy density. The examples of TNT and CL-20\nillustrate the inadequacies of existing research. By contrasting the planar symmetrical structures of\nconventional energetic materials with the successful three-dimensional complex configurations of\namorphous forms in pharmaceuticals, the concept of “structural frustration” is introduced as a\ndesign principle. Further, DATNBI is employed as a model system to elucidate how its intrinsic\nnon-planar configuration and hydrogen bonding synergies can be leveraged to validate the design\nconcept of externally additive-free, stable amorphous energetic materials.\n2. The newly added portions need language editing.\nResponse: We thank the reviewer for pointing this out. We agree that the clarity and quality of the\nlanguage are paramount. To ensure the manuscript meets the high standard of Nature\nCommunications, the entire manuscript, with special attention paid to the newly added portions,\nhas been professionally edited. The editing focused on improving grammar, syntax, spelling, word\nchoice, and overall fluency.\n3. AEM-DATNBI exhibits a higher glass transition temperature (Tg = 59.67 °C), than TNT, (Tg =\n−25.6 °C). Why this is favorable from an application point view?\nResponse: We appreciate the reviewer's comment. The higher glass transition temperature (T )\ng\nrepresents a key advantage of AEM-DATNBI over TNT, directly translating into two significant\napplication benefits. The glass transition temperature (T ) marks the critical point where\ng\namorphous materials transition from a rigid glassy state to a highly elastic state. AEM-DATNBI's\nhigh T of ~ 60 °C means it maintains a rigid glassy state at room temperature and even higher\ng\ntemperatures. Its molecular motion is frozen, effectively preserving its amorphous structure with\nhigh physical stability and low susceptibility to spontaneous crystallization. In contrast, TNT's\nextremely low T (-25.6 °C) implies it exists in a highly elastic or viscous flow state at common\ng\nambient temperatures (e.g., 25 °C). With sufficient molecular mobility, it exhibits a strong\ntendency toward spontaneous recrystallization. This instability can lead to phase separation,\ninternal defects, or performance degradation during storage or use, severely compromising\nreliability.\nFrom a processing perspective, the glass transition temperature (T ) defines the material's\ng\nthermoplastic processing window. AEM-DATNBI exhibits a T of approximately 60 °C, providing\ng\nan ideal and easily controllable processing range for hot-press molding. During operation, heating\nthe material to a temperature slightly above its T (e.g., 60–80 °C) causes it to soften, enabling\ng\ncomplete filling of complex mold cavities. Subsequent cooling to room temperature (well below\nits T ) rapidly solidifies it into a rigid, dimensionally stable solid. This plastic-like controllable\ng\nprocessability makes it highly suitable for manufacturing complex geometries. Furthermore, as\ndemonstrated in Figure 4a, the material exhibits self-healing capabilities within this processing\nwindow. In contrast, TNT possesses a T far below room temperature, lacking a practical\ng\nprocessing window. Under conventional conditions, it struggles to form stable, defect-free solid\nfilms or structures, presenting significant challenges in both process ability and reliability.\nThus, the significantly elevated T provides the physical foundation for AEM-DATNBI's\ng\nexceptional structural stability and superior formability. These properties collectively constitute its\ndecisive advantage over amorphous energetic materials with low glass transition temperatures in\npractical applications.\n4. \"AEM-DATNBI achieved near-complete mass loss (97.4%) compared to crystalline samples\n(77.3%, Fig. 5b). This 20.1% increase in mass loss highlights the critical role of structural disorder\nin promoting complete molecular disintegration under thermal stress.\" This statement and\nobservation needs a scientifically sound explanation. Why the thermal decomposition behavior\nshould change? The DATNBI is a CHNO compound, still no residue after thermal analysis, why?\nFigure S22. The TG/DSC curves for the thermal decomposition of AEM-DATNBI (a) and CEM-\nDATNBI (d). The FT-IR spectra of gaseous products for AEM-DATNBI (b, c) and CEM-DATNBI\n(e, f)\nResponse: We are most grateful for raising this crucial question, which has prompted us to\nconduct a more thorough investigation into the underlying mechanisms governing the variations in\nthermal decomposition behaviour of amorphous materials. Acting upon your suggestion, we have\nnot only supplemented the manuscript with detailed mechanistic explanations but, more\nimportantly, incorporated key data from decomposition gas product analysis and thermal\ndecomposition activation energy studies. These data provide direct evidence supporting our\ninterpretations. The thermal decomposition activation energy of amorphous samples (AEM-\nDATNBI) is typically lower than that of crystalline samples (CEM-DATNBI). This reduction in\nactivation energy diminishes the reaction barrier during the initial stages of pyrolysis, facilitating\nmolecular fragmentation and recombination. Consequently, it promotes the formation and\ndiffusion of reaction intermediates. The composition of pyrolysis gases was analysed to\ninvestigate the nature of the decomposition process. The combined analytical results indicate that\nAEM-DATNBI and CEM-DATNBI exhibit no significant differences in the typical of pyrolysis\ngases produced (Figure S22a-b and Figure S22c-d), yet their relative gas product concentrations\nshow marked variations (Figure S23). Compared to CEM-DATNBI, AEM-DATNBI gas products\ndemonstrate significantly elevated relative concentrations of N₂O/CO₂ (48% vs 45%) and NO (27%\nvs 16%). Conversely, the relative content of CO decreased substantially (6% vs 26%). This shift in\ngas distribution is crucial. CO₂, and H₂O are products of highly oxidative processes, whereas CO\nis a hallmark of incomplete oxidation. This distribution clearly indicates that the pyrolysis process\nin the amorphous sample proceeds towards more thorough and complete oxidation. We hypothesis\nthat the ordered structure of the compact crystalline sample (CEM-DATNBI) restricts the diffusion\nof reaction intermediates. Decomposition is likely initiated at specific lattice defects, where\npartially oxidized intermediates (such as precursors to CO formation) become trapped within the\ndense framework. As a result, these trapped species are unable to participate fully in secondary\noxidation processes and are eventually released as CO. This leads to incomplete mass loss (77.3%)\nand an elevated CO yield.\nConversely, the amorphous properties of AEM-DATNBI imply a molecular arrangement\ncharacterized by long-range disorder and loose packing. This structure not only facilitates the\nonset of decomposition but also allows the initial reaction intermediates to diffuse rapidly and\nparticipate fully in secondary oxidation steps. Consequently, these intermediates that might\notherwise form CO or residues gain greater opportunity to react further with reactive oxygen\nspecies (such as NO₂, O₂ etc.), thus generating more stable final gaseous products: N₂O, CO₂,\nNO,\nand H₂O. This process resembles a “more efficient and thorough combustion,” leading to a near-\ncomplete mass loss of 97.4%. Based on the above analysis, we have added a new discussion\nsection to the “Energy Release and Mechanical sensitivity of AEM-DATNBI” section of the\nmanuscript, systematically explaining why structural disorder promotes more complete thermal\ndecomposition. We have incorporated the aforementioned new data and comprehensive theoretical\nexposition into the revised manuscript (see Manuscript, “Energy Release and Mechanical\nsensitivity of AEM-DATNBI” section). We believe that these supplementary experimental data\nand in-depth discussion provide a robust and scientifically sound explanation for our observations.\nFigure S23. the relative content comparison of typical products.\n5. The purity (LC & NMR) of DATNBI to be included in the supporting information.\nResponse: We appreciate the reviewers for examining our manuscript and providing valuable\nfeedback. Regarding your suggestion to “The purity (LC & NMR) of DATNBI to be included in\nthe supporting information.” we fully agree that this is crucial for verifying the quality of material.\nWe have incorporated your recommendation and added the liquid NMR spectrum of DATNBI to\nthe supporting information. The liquid chromatography spectrum of DATNBI is provided in\nSupplementary Figure S10 and Figure S13, showing a single, sharp main peak. Calculated\nchemical purity exceeds 99.8% (external standard method), with corresponding computational\ndetails supplemented in the experimental section “S1.2 Purity and Characterization of DATNBI.”\nTo further address the reviewer’s comment and offer a more comprehensive purity assessment,\nwe\nhave now added the Nuclear Magnetic Resonance (NMR) characterization data. The NMR spectra\nwere acquired on a Bruker Avance NEO 400 MHz spectrometer using DMSO‑d6 as the solvent. In\nthe 13C NMR spectra of AEM-DATNBI, the chemical shifts of the imidazole ring were observed\nat 135.7, 134.3, and 131.6 ppm, while the corresponding 1H NMR signal appeared at 6.98 ppm.\nThese values are consistent with those reported for CEM-DATNBI1‑2. The 1H and 13C NMR\n)%(\ntnetnoc\nnoitaleR\n1\n1\n2\n0\n8\n6\n4\n2\n0\n0\n0\n0\n0\n0\n4\n2\n1\n-\nN\n8\n7\n6 %\n2\n%\n%\n%\nA\nO\nT\n/C\nN\nO\nB\nN O\nC\nC\nE\nO\nM\n4\n1\n2\n1\n-\n5\n6\n6\n%\n%\n%\n%\nA\nH\nT\nO\nB I\nspectra of DATNBI are now provided in Supplementary Figures S12.\n7×106\ny=8542429.87x-156647.29\n6×106 R2=0.992\n)\nn\nim\n5×106\n*\nV\nm\n(\na\n4×106\ne\nr\na\nk 3×106\na\ne\nP\n2×106\n1×106\n0.20.2 0.3 0.4 0.5 0.6 0.7 0.80.9\nConcentration (mg ml-1)\nFig. S12. The regression analysis of the peak area of DATNAI versus its’ concentration\nTable S2. The retention time and peak area of CEM-DATNBI and AEM-DATNBI\nName Retention time Peak area Actual concentration Theoretical\n(min) (mV min) (mg ml-1) concentration (mg ml-1)\nCEM- 11.79 1521490 0.200 -\nDATNBI-1\nCEM- 11.81 4151874 0.496 -\nDATNBI-2\nCEM- 11.82 5495560 0.664 -\nDATNBI-3\nCEM- 11.83 6331523 0.762 -\nDATNBI-4\nAEM- 11.84 2658248 0.329 0.330\nDATNBI\nFigure S13. (a) 1C NMR spectra of AEM-DATNBI and CEM-DATNBI, (b) 1H NMR spectra of\nAEM-DATNBI and CEM-DATNBI.\n1. Ma, Q., Lu, H., Liao, L., Fan, G. & Huang, J. One-Pot Synthesis, Crystal Structure, and\nThermal Decomposition Behavior of 1,1ʹ-Diamino-4,4ʹ,5,5ʹ-Tetranitro-2,2ʹ-Biimidazole. J. Energ.\nMater. 35, 239–249 (2017).\n2. Yin, P., He, C. & Shreeve, J. M. Fully C/N‐polynitro‐functionalized 2,2′‐biimidazole\nderivatives as nitrogen‐ and oxygen‐rich energetic salts. Chem. – Eur. J. 22, 2108–2113 (2016).\n6. Reference 54 does not mention about any BAM method. A brief description of IS and FS\ndetermination to be included in the supporting information.\nResponse: We sincerely thank the reviewer for highlighting these two important points. Please\nfind our responses below.\nCorrection of Reference 54: We apologize for the error in citation. The reviewer is correct that\nReference 54 was not appropriate for the BAM method. We have now removed the incorrect\nreference and cited the proper, standard reference that describes the BAM friction sensitivity test.\nThis reference is now included as [New Reference 60] in the revised manuscript on page.\nInclusion of FS and IS Determination Description: Following the reviewer's excellent suggestion,\nwe have added a new section in the Supporting Information titled “S1.1 Experimental Methods for\nImpact Sensitivity (IS) and Friction Sensitivity (FS) Testing.”\nThis section provides a concise description of the standardized testing procedures we employed:\nFriction sensitivity was evaluated using a BAM friction sensitivity tester following the procedure\ndescribed in the UN Transport of Dangerous Goods, Manual of Tests and Criteria.\nImpact Sensitivity (IS): The test was performed using a BAM Fallhammer apparatus according to\nthe UN Manual of Tests and Criteria. A 40 mm³ sample was taken using a cylindrical measure (3.7\nmm diameter × 3.7 mm) and enclosed in an impact device consisting of two coaxial steel cylinders\nguided within a hollow cylindrical steel ring. A weight was dropped from progressively adjusted\nheights onto the upper platen to apply impact energy, until either decomposition or no reaction\nwas observed. At this energy level, the test was repeated six times. If no explosion occurred in any\nof the six trials, the corresponding impact energy was recorded as the minimum impact energy,\nexpressed in J.\nFriction Sensitivity (IS): The test was conducted using a BAM friction sensitivity apparatus\nfollowing the same standard. For our powdered sample, a quantity of approximately 10 mm³ was\ntaken using a cylindrical measure (2.3 mm diameter × 2.4 mm deep) and placed on the plate. The\nfirmly clamped porcelain peg was carefully lowered onto the sample. The loading arm was then\nloaded with the required weights. The switch was operated to move the porcelain plate relative to\nthe stationary porcelain peg. Care was taken to ensure the peg rested fully on the sample, that\nthere is enough of the substance to come under the peg when the porcelain plate moves in front of\nthe peg. The friction sensitivity was reported as the lowest load in Newtons (N) at which ignition,\nexplosion, or a positive reaction (such as audible crackling, sparking, or decomposition) was\nobserved in at least one out of six trials.\nResponse to Reviewers' Comments\nWe sincerely appreciate the editors and reviewers for their time and valuable comments on\nour manuscript. We are delighted that the reviewers found our previous revisions have\nsubstantially improved the manuscript. Following the remaining comments and editorial\nsuggestions, we have conducted comprehensive revisions to fully address all concerns. The\npoint-by-point responses are detailed below.\nReviewer #3 (Remarks to the Author):\nWe sincerely thank you for your thorough review of the revised manuscript and for your valuable\nsuggestions. These recommendations have further enhanced the scientific rigor and clarity of\nexpression in our paper. We have carefully revised the manuscript according to each of your\nsuggestions. The specific modifications are as follows:\n(1) In response to Reviewer #3, comment #4; The logic presented is generally acceptable; however,\nthe explanation requires some revision. The percentage formation of CO and CO is used to explain\n2\nthe difference in the mass of the DATNBI residue. Yet it must be noted that the total amount of\ncarbon remains the same, regardless of whether it is amorphous or crystalline. In addition, oxygen\nis readily available both from the molecule itself and from the environment (since a standard TGA\ninstrument is not sealed against oxygen ingress). Given that both CO and CO are gaseous products,\n2\nit is unclear why carbon would remain in one case but not in the other. This point requires further\nclarification.\nResponse: Thank you very much for your insightful and constructive comments. You correctly point\nout that the total amount of carbon is conserved and that oxygen is obtained from molecules and the\nexperimental environment. We agree that explaining the difference in residue mass solely by the\nratio change of gaseous products CO and CO₂ without elucidating the underlying physicochemical\nmechanism leading to solid carbon residue is indeed insufficiently clear.\nYour question touches upon a key finding in our research. Amorphous structures significantly\ninfluence the integrity of decomposition pathways by altering the local environment and diffusion\nbehavior of reaction intermediates, thereby suppressing the formation of carbon-rich solid residues\nthat are difficult to oxidize. Crystalline DATNBI (CEM-DATNBI) exhibits a dense, ordered\nmolecular packing structure. During early pyrolysis, reactions may preferentially initiate at grain\nboundaries or defects. Partially oxidized intermediates (e.g., CO precursors) generated are restricted\nfrom diffusing out of the dense crystalline structure. These carbon-rich intermediates, “trapped”\nwithin or on the crystal surface, cannot fully contact oxygen for deep oxidation. Consequently, they\nare more prone to side reactions like polymerization and aromatization, ultimately forming highly\nthermally stable, non-volatile carbonaceous solid residues that resist further gasification. This\nexplains the incomplete mass loss (77.3%) and relatively high CO yield. In contrast, amorphous\nDATNBI (AEM-DATNBI) exhibits a structure characterized by long-range disorder and large free\nvolume. This structure provides more unobstructed pathways for the diffusion of reactants and\nintermediates. Consequently, intermediates generated during decomposition can rapidly diffuse and\nmix thoroughly with oxygen atoms originating from within the molecules, enabling a more complete\noxidation reaction. This significantly suppresses the formation of carbon-rich solid residues,\nresulting in final reaction products consisting almost entirely of gaseous N₂O, CO₂, H₂O, and other\ncomponents. Consequently, near-complete mass loss (97.4%) is achieved.\nIn short, the difference in residue mass primarily stems from the amorphous structure inhibiting the\nformation of solid carbon residues, rather than simply altering the gas-phase ratio of CO and CO₂.\nThe reduced CO yield results from more complete oxidation, not as a direct cause of decreased\nresidues; the fundamental reason lies in the reaction pathway shifting toward more thorough\noxidation, thereby avoiding the generation of solid carbon.\nWe believe that the above modifications and clarifications have fully addressed your concerns and\nprovide a more in-depth and logically consistent explanation of the relevant mechanisms. Thank\nyou once again for helping us enhance the quality of our paper.\n(2) Though the work is novel over emphasis as novel energetic material such as \"The emergence of\namorphous energetic materials pioneers an entirely new, unexplored research frontier in explosives\nscience. Its significance extends far beyond the discovery of a novel material, representing a\nparadigm shift in research and a transformative future for the industry.\" may be avoided\nResponse: We fully accept the reviewers' suggestions and have systematically revised the entire\nmanuscript according to their feedback and the journal's formatting requirements. We have removed\nall subjective and exaggerated language throughout the manuscript. The example sentence on line\n95 has been revised to: “The emergence of amorphous energetic materials pioneers an unexplored\nresearch area in explosives science. Its significance extends beyond the discovery of a new material,\nrepresenting a promising direction for research and industry.”\nOn line 218 has been revised to: “While AEM-DATNBI has achieved a degree of structural stability,\nfurther improvements are necessary to ensure that amorphous energetic materials remain stable\nunder complex and variable application conditions.”\nOn line 245 has been revised to: “AEM-DATNBI exhibits a low mechanical sensitivity, which can\nbe ascribed to its uniform internal structure and low-defect characteristics. These features reduce\nhot-spot nucleation in amorphous matrix.”\nWe have ensured that the tone throughout the text remains scientific and neutral, focusing on\nreporting data, analyzing results, and explaining mechanisms.\n(3) Title doesn't read smooth need to be refined.\nResponse: Thank you for bringing this to our attention. We have revised the title in accordance with\nthe specific recommendations provided by the journal editor in the Author Checklist: “Entropy-\nMediated Solidification Stabilizes and Enhances Energetic Release in Amorphous Energetic\nMaterials.” The revised title has been updated in all manuscript files."}, {"round": 2, "reviewer_comments": {"reviewer_1": "I recommend the publication of this manuscript in its current form.", "reviewer_3": "The authors have thoroughly revised the manuscript, and its overall perspective is now acceptable. However, the following points must be addressed before it can be considered for publication.\n1. The focus of the abstract and introduction is too vague. Introduction needs to be refined extensively and made technically sound.\n2. The newly added portions need language editing.\n3. AEM-DATNBI exhibits a higher glass transition temperature (Tg = 59.67 °C), than TNT, (Tg = −25.6 °C). Why this is favorable from an application point view?\n4. \"AEM-DATNBI achieved near-complete mass loss (97.4%) compared to crystalline samples (77.3%, Fig. 5b). This 20.1% increase in mass loss highlights the critical role of structural disorder in promoting complete molecular disintegration under thermal stress.\" This statement and observation needs a scientifically sound explanation. Why the thermal decomposition behavior should change? The DATNBI is a CHNO compound, still no residue after thermal analysis, why?\n5. The purity (LC & NMR) of DATNBI to be included in the supporting information.\n6. Reference 54 does not mention about any BAM method. A brief description of IS and FS determination to be included in the supporting information."}, "author_response": "Response to Reviewers' Comments\nWe sincerely appreciate the editors and reviewers for their time and valuable comments on\nour manuscript. We are delighted that the reviewers found our previous revisions have\nsubstantially improved the manuscript. Following the remaining comments and editorial\nsuggestions, we have conducted comprehensive revisions to fully address all concerns. The\npoint-by-point responses are detailed below.\nReviewer #1 (Remarks to the Author):\nI recommend the publication of this manuscript in its current form.\nResponse: Thank you for reviewing our manuscript and for your high regard for our research. We\nare most gratified that you consider this paper acceptable for publication ‘in its current form’ (‘I\nrecommend the publication of this manuscript in its current form’). Once again, we extend our\nsincere gratitude for your valuable time and encouragement.\nReviewer #3 (Remarks on response to Reviwer 2)\n(1) I do agree with the reviewer's comment that \" Thus, though this reviewer finds nothing\ntechnically wrong with the manuscript, it also is not fundamentally novel\". It can be verified by\nthe references provided by the reviewer.\nResponse: We sincerely thank the reviewer for this critical comment, which allows us to better\narticulate the fundamental novelty of our work.\nAlthough amorphous as a material state has been applied in multiple fields such as\npharmaceuticals, it is not an innovative concept in itself. However, its introduction into the field of\nenergetic materials represents a fundamental breakthrough. This integration is not a simple\ntechnology transplant but rather a complete subversion of the long-standing paradigm in\nexplosives research, which has traditionally relied on crystalline structures. It has created an\nentirely new material foundation of “amorphous energetic materials,” thereby opening an\nunprecedented research direction. This breakthrough has pioneered an unprecedented research\ndirection, accelerating transformative advancements in explosive material development,\nmanufacturing processes, and performance enhancement, thereby opening new avenues for\nexploration and innovation in the field of explosives. This manuscript successfully achieves the\nstabilization and preparation of such high-energy rigid organic small molecules. With the unique\namorphous structure obtained, the material not only effectively suppresses hot spot formation and\nsignificantly enhances safety but also simultaneously accelerates energy release, enabling faster\ncombustion and more complete decomposition. With a glass transition temperature of 59.67°C,\nthis material provides an ideal thermoplastic window for processing, laying the foundation for\nfuture research on binderless forming of energetic materials. It not only simplifies manufacturing\nprocesses but also avoids dilution by inert components, theoretically unlocking immense potential\nfor higher energy density in amorphous energetic materials. Thus, the emergence of amorphous\nenergetic materials pioneers an entirely new, unexplored research frontier in explosives science.\nIts significance extends far beyond the discovery of a novel material, representing a paradigm shift\nin research and a transformative future for the industry.\nRegarding the references cited by the reviewers, we have conducted a detailed comparative\nanalysis. We contend that our work exhibits significant distinctions from these distinguished\nstudies. As noted in the references provided by the reviewers1, high molecular weight, structurally\ncomplex and flexible organic molecules, their abundant functional groups and conformational\ndiversity, which facilitate the formation of amorphous states. In contrast, we concentrate on rigid\norganic small molecules (typically comprising single or minimal ring systems substituted with\nfunctional groups such as –NO₂ or –NH₂). Such molecules are widely recognized in the literature\nas systems that are extremely difficult to form and stabilize in an amorphous state due to strong\nintermolecular interactions and restricted conformational flexibility4. Therefore, this study directly\naddresses the challenge of preparing amorphous states from rigid organic small molecules and\ntackles the scientific problem of synthesizing amorphous energetic materials. Methodologically,\nthe pharmaceutical field employs solid dispersion technology for amorphization5-6, aiming to\neffectively enhance the solubility and biocompatibility of poorly soluble components. However,\nits characteristic of low drug loading capacity limits its application in the field of energetic\nmaterials. The reason lies in the fact that energetic materials must strictly limit the proportion of\npolymeric excipients to ensure their destructive effectiveness. This requirement further increases\nthe difficulty of manufacturing amorphous energetic materials. Instead, we selected a highly\nchallenging molecular system, expanded the application of amorphous materials into new domains,\nand revealed a series of novel performance characteristics.\nIn response to the valuable comments from the reviewers, we have carefully revised the abstract\nand introduction sections of the manuscript. This revision further clarifies the core scientific\nquestions addressed in this study while more prominently highlighting the distinctions between\nour work and existing research, as well as the unique innovative value of our contributions.\n1. Zhao, X. et al. Prediction of the synergistic glass transition temperature of coamorphous\nmolecular glasses using activity coefficient models. Mol. Pharmaceutics 18, 3439–3451 (2021).\n2. Cheng, S. & McKenna, G. B. Isothermal crystallization and time–temperature transformation\nof amorphous nifedipine: a case of polymorphism formation and conversion. Mol. Pharmaceutics\n18, 2786–2802 (2021).\n3. Bhardwaj, S. P. et al. Correlation between molecular mobility and physical stability of\namorphous itraconazole. Mol. Pharmaceutics 10, 694–700 (2013).\n4. Zhou, D., Schmitt, E. A., Law, D., Brackemeyer, P. J. & Zhang, G. G. Z. Assessing Physical\nStability Risk Using the Amorphous Classification System (ACS) Based on Simple Thermal\nAnalysis. Mol. Pharmaceutics 16, 2742–2754 (2019).\n5. Lalge, R., Kumar, N. S. K. & Suryanarayanan, R. Understanding the effect of nucleation in\namorphous solid dispersions through time–temperature transformation. Mol. Pharmaceutics 20,\n4196–4209 (2023).\n6. Nagapudi, K. & Jona, J. Amorphous active pharmaceutical ingredients in preclinical studies:\npreparation, characterization, and formulation. Curr. Bioact. Compd. 4, 213–224 (2008).\n(2) Thus the novelty remains with the materials used and the application area 'high energy\nmaterials'.\nResponse: We thank the reviewer for this positive comment regarding the novelty of our work\nlying in the materials and their application in high-energy materials. In response to this point, we\nhave revised the manuscript to focus on this core aspect. Specifically, as suggested, we have now\nstrengthened the Introduction and Abstract to unequivocally highlight our amorphous energetic\nmaterial as a novel functional material system. The relevant changes can be found on the revised\nmanuscript.\n(3) However, the quality and standard of reported manuscripts (and the characterisation\ntechniques) used are not comparable with that of the submitted manuscripts, making the submitted\nmanuscript a definitely superior one.\nResponse: We sincerely thank the reviewer for this generous assessment and for recognizing the\nrigorous standards we have strived to uphold in this study. Our research has successfully achieved\na stable amorphous state for rigid small molecules by modulating molecular planarity, steric\nhindrance, and intermolecular interactions (hydrogen bonding networks), thereby actively\nsuppressing the crystallization process. Furthermore, we have elucidated the critical role of this\ndisordered structure in determining material properties.\n(4) The real application of this method/materials as energetic material is doubtful, (I too have\ncommented that in my review) because of the lower density exhibited by amorphous materials.\nResponse: We are most grateful for your profound and constructive comments. The point you\nraised concerning the impact of lower density in amorphous materials upon their application\npotential is indeed a crucial issue within our research work. We fully concur that density\nconstitutes one of the core parameters for energetic materials. However, we think that the overall\nperformance and applicability of energetic material are determined by a balance of multiple\nproperties, and our work demonstrates that amorphous DATNBI offers a uniquely favorable\nbalance that can be highly advantageous for specific applications. In practical applications,\nconventional crystalline energetic materials (such as TATB and RDX) exhibit brittleness, making\nit difficult to meet the mechanical and structural requirements of weapon components through\ndirect pressing alone. Consequently, polymer bonded explosives (PBX) were developed and\nwidely adopted for manufacturing weapon parts. This technology involves dispersing high-energy\nexplosive particles within a polymeric binder matrix, thereby retaining high energy content while\nachieving excellent processability and mechanical integrity1-2. However, since the binder itself\neither does not participate or only minimally contributes to energy release, it reduces the energetic\ndensity of the system, thereby diminishing both detonation velocity and pressure3. Thus, under\nidentical conditions of high-energy component content, PBX typically demonstrates lower density,\ndetonation velocity, and pressure compared to its pure crystalline form (Table 1). In contrast, the\namorphous energetic materials prepared in this study exhibit exceptional thermoplastic\nprocessability owing to their unique glass transition characteristics, enabling the formation of\ncharges composed entirely of pure energetic components without relying on any binders. This\nimplies that although the density of the amorphous material may be lower, its charge density\nequals its material density. As demonstrated by experimental data and reference (Table 1), typical\nPBX charge densities (~1.8 g/cm³) are comparable to the density of our amorphous DATNBI\nmaterial (~1.89 g/cm³), with detonation velocities and pressures reaching 8,840 m/s and 34 GPa,\nrespectively—values that are either at the same magnitude or even more advantageous for the\nlatter. Therefore, in the final charge configuration, amorphous materials comprising 100%\nenergetic components hold promise for surpassing traditional binder-containing PBX systems in\noverall performance.\nTable 1. Explosive formulation data.\nModel number ρa (g/cm3) Vb (m/s) Explosive (wt%) Binder (wt%) Source\nAEM-DATNBI 1.89 8840 DATNBI(100 %) -- This work\nHMX 1.89 9110 HMX(100 %) -- 4\nEstane (2.5%)\nPBX 9501 1.83 8790 HMX(95 %) BDNPA/BDNPF 5\n(2.5%)\nNC (3%), CEF\nPBX 9404 1.85 8802 HMX(94 %) 4\n(3%)\nViton VTR-5883\nPBX 9012 1.84 8590 HMX(90 %) 6\n(10%)\nPBX 9011 1.77 8500 HMX(90 %) Estane 5703 (10%) 4\na Explosive density. b Detonation velocity.\n1. Talawar, M. B., Jangid, S. K., Nath, T., Sinha, R. K. & Asthana, S. N. New directions in the\nscience and technology of advanced sheet explosive formulations and the key energetic materials\nused in the processing of sheet explosives: emerging trends. J. Hazard. Mater. 300, 307–321\n(2015).\n2. Sun, H., Fan, X., Zhan, M., Guo, J. & Zhang, J. Mechanism of uneven densification in PBX\ncompression molding. Int. J. Mech. Sci. 282, 109683 (2024).\n3. He, Z. et al. Effect of 2,4,6‐triamino‐3,5‐dinitropyridine‐1‐oxide on the properties of\n1,3,5‐trinitro‐1,3,5‐triazinane‐based PBX explosives. Propellants, Explos., Pyrotech. 46, 530–536\n(2021).\n4. T.R. Gibbs, A. Popolato, LASL explosive property data, University of California Press, 1980.\n5. Chiquete, C., Short, M., Voelkel, S. J., Anderson, E. K. & Jackson, S. I. Detonation shock\ndynamics modeling and calibration of the HMX-based conventional high explosive PBX 9501\nwith application to the two-dimensional circular arc geometry. Combust. Flame 222, 213–232\n(2020).\n6. Anderson, E. K., Chiquete, C., Jackson, S. I., Chicas, R. I. & Short, M. The comparative\neffect of HMX content on the detonation performance characterization of PBX 9012 and PBX\n9501 high explosives. Combust. Flame 230, 111415 (2021).\nReviewer #3 (Remarks to the Author):\nThe authors have thoroughly revised the manuscript, and its overall perspective is now acceptable.\nHowever, the following points must be addressed before it can be considered for publication.\n1. The focus of the abstract and introduction is too vague. Introduction needs to be refined\nextensively and made technically sound.\nResponse: We sincerely appreciate your review of our manuscript and the valuable feedback you\nprovided. Your observation that the abstract and introduction sections were “The focus of the\nabstract and introduction is too vague.” is very insightful and crucial for improving the\nmanuscript's quality. We have thoroughly rewritten and substantially revised these sections based\non your suggestions. The abstract elucidates the core challenge that rigid organic small molecules\nface in forming stable amorphous phases due to their strong crystallisation tendency, particularly\nwithin the field of energetic materials where high energy density must be maintained. The revised\nversion systematically outlines strategies for achieving structural stability through steric hindrance\nand intermolecular interactions. It reveals the synergistic stabilisation mechanism involving non-\nplanar configurations and hydrogen-bond networks. It summarises improvements in\nmaterial\nsafety, combustion behaviour, and decomposition performance. The introduction commences with\nthe general concept of amorphous materials, focusing on the specific challenges faced by ‘rigid\norganic small molecules’ and “energetic materials”. It emphasises the demand within this field for\npure-phase, stable amorphous energetic compounds, highlighting the limitations of traditional\nexogenous stabilisation strategies in reducing energy density. The examples of TNT and CL-20\nillustrate the inadequacies of existing research. By contrasting the planar symmetrical structures of\nconventional energetic materials with the successful three-dimensional complex configurations of\namorphous forms in pharmaceuticals, the concept of “structural frustration” is introduced as a\ndesign principle. Further, DATNBI is employed as a model system to elucidate how its intrinsic\nnon-planar configuration and hydrogen bonding synergies can be leveraged to validate the design\nconcept of externally additive-free, stable amorphous energetic materials.\n2. The newly added portions need language editing.\nResponse: We thank the reviewer for pointing this out. We agree that the clarity and quality of the\nlanguage are paramount. To ensure the manuscript meets the high standard of Nature\nCommunications, the entire manuscript, with special attention paid to the newly added portions,\nhas been professionally edited. The editing focused on improving grammar, syntax, spelling, word\nchoice, and overall fluency.\n3. AEM-DATNBI exhibits a higher glass transition temperature (Tg = 59.67 °C), than TNT, (Tg =\n−25.6 °C). Why this is favorable from an application point view?\nResponse: We appreciate the reviewer's comment. The higher glass transition temperature (T )\ng\nrepresents a key advantage of AEM-DATNBI over TNT, directly translating into two significant\napplication benefits. The glass transition temperature (T ) marks the critical point where\ng\namorphous materials transition from a rigid glassy state to a highly elastic state. AEM-DATNBI's\nhigh T of ~ 60 °C means it maintains a rigid glassy state at room temperature and even higher\ng\ntemperatures. Its molecular motion is frozen, effectively preserving its amorphous structure with\nhigh physical stability and low susceptibility to spontaneous crystallization. In contrast, TNT's\nextremely low T (-25.6 °C) implies it exists in a highly elastic or viscous flow state at common\ng\nambient temperatures (e.g., 25 °C). With sufficient molecular mobility, it exhibits a strong\ntendency toward spontaneous recrystallization. This instability can lead to phase separation,\ninternal defects, or performance degradation during storage or use, severely compromising\nreliability.\nFrom a processing perspective, the glass transition temperature (T ) defines the material's\ng\nthermoplastic processing window. AEM-DATNBI exhibits a T of approximately 60 °C, providing\ng\nan ideal and easily controllable processing range for hot-press molding. During operation, heating\nthe material to a temperature slightly above its T (e.g., 60–80 °C) causes it to soften, enabling\ng\ncomplete filling of complex mold cavities. Subsequent cooling to room temperature (well below\nits T ) rapidly solidifies it into a rigid, dimensionally stable solid. This plastic-like controllable\ng\nprocessability makes it highly suitable for manufacturing complex geometries. Furthermore, as\ndemonstrated in Figure 4a, the material exhibits self-healing capabilities within this processing\nwindow. In contrast, TNT possesses a T far below room temperature, lacking a practical\ng\nprocessing window. Under conventional conditions, it struggles to form stable, defect-free solid\nfilms or structures, presenting significant challenges in both process ability and reliability.\nThus, the significantly elevated T provides the physical foundation for AEM-DATNBI's\ng\nexceptional structural stability and superior formability. These properties collectively constitute its\ndecisive advantage over amorphous energetic materials with low glass transition temperatures in\npractical applications.\n4. \"AEM-DATNBI achieved near-complete mass loss (97.4%) compared to crystalline samples\n(77.3%, Fig. 5b). This 20.1% increase in mass loss highlights the critical role of structural disorder\nin promoting complete molecular disintegration under thermal stress.\" This statement and\nobservation needs a scientifically sound explanation. Why the thermal decomposition behavior\nshould change? The DATNBI is a CHNO compound, still no residue after thermal analysis, why?\nFigure S22. The TG/DSC curves for the thermal decomposition of AEM-DATNBI (a) and CEM-\nDATNBI (d). The FT-IR spectra of gaseous products for AEM-DATNBI (b, c) and CEM-DATNBI\n(e, f)\nResponse: We are most grateful for raising this crucial question, which has prompted us to\nconduct a more thorough investigation into the underlying mechanisms governing the variations in\nthermal decomposition behaviour of amorphous materials. Acting upon your suggestion, we have\nnot only supplemented the manuscript with detailed mechanistic explanations but, more\nimportantly, incorporated key data from decomposition gas product analysis and thermal\ndecomposition activation energy studies. These data provide direct evidence supporting our\ninterpretations. The thermal decomposition activation energy of amorphous samples (AEM-\nDATNBI) is typically lower than that of crystalline samples (CEM-DATNBI). This reduction in\nactivation energy diminishes the reaction barrier during the initial stages of pyrolysis, facilitating\nmolecular fragmentation and recombination. Consequently, it promotes the formation and\ndiffusion of reaction intermediates. The composition of pyrolysis gases was analysed to\ninvestigate the nature of the decomposition process. The combined analytical results indicate that\nAEM-DATNBI and CEM-DATNBI exhibit no significant differences in the typical of pyrolysis\ngases produced (Figure S22a-b and Figure S22c-d), yet their relative gas product concentrations\nshow marked variations (Figure S23). Compared to CEM-DATNBI, AEM-DATNBI gas products\ndemonstrate significantly elevated relative concentrations of N₂O/CO₂ (48% vs 45%) and NO (27%\nvs 16%). Conversely, the relative content of CO decreased substantially (6% vs 26%). This shift in\ngas distribution is crucial. CO₂, and H₂O are products of highly oxidative processes, whereas CO\nis a hallmark of incomplete oxidation. This distribution clearly indicates that the pyrolysis process\nin the amorphous sample proceeds towards more thorough and complete oxidation. We hypothesis\nthat the ordered structure of the compact crystalline sample (CEM-DATNBI) restricts the diffusion\nof reaction intermediates. Decomposition is likely initiated at specific lattice defects, where\npartially oxidized intermediates (such as precursors to CO formation) become trapped within the\ndense framework. As a result, these trapped species are unable to participate fully in secondary\noxidation processes and are eventually released as CO. This leads to incomplete mass loss (77.3%)\nand an elevated CO yield.\nConversely, the amorphous properties of AEM-DATNBI imply a molecular arrangement\ncharacterized by long-range disorder and loose packing. This structure not only facilitates the\nonset of decomposition but also allows the initial reaction intermediates to diffuse rapidly and\nparticipate fully in secondary oxidation steps. Consequently, these intermediates that might\notherwise form CO or residues gain greater opportunity to react further with reactive oxygen\nspecies (such as NO₂, O₂ etc.), thus generating more stable final gaseous products: N₂O, CO₂,\nNO,\nand H₂O. This process resembles a “more efficient and thorough combustion,” leading to a near-\ncomplete mass loss of 97.4%. Based on the above analysis, we have added a new discussion\nsection to the “Energy Release and Mechanical sensitivity of AEM-DATNBI” section of the\nmanuscript, systematically explaining why structural disorder promotes more complete thermal\ndecomposition. We have incorporated the aforementioned new data and comprehensive theoretical\nexposition into the revised manuscript (see Manuscript, “Energy Release and Mechanical\nsensitivity of AEM-DATNBI” section). We believe that these supplementary experimental data\nand in-depth discussion provide a robust and scientifically sound explanation for our observations.\nFigure S23. the relative content comparison of typical products.\n5. The purity (LC & NMR) of DATNBI to be included in the supporting information.\nResponse: We appreciate the reviewers for examining our manuscript and providing valuable\nfeedback. Regarding your suggestion to “The purity (LC & NMR) of DATNBI to be included in\nthe supporting information.” we fully agree that this is crucial for verifying the quality of material.\nWe have incorporated your recommendation and added the liquid NMR spectrum of DATNBI to\nthe supporting information. The liquid chromatography spectrum of DATNBI is provided in\nSupplementary Figure S10 and Figure S13, showing a single, sharp main peak. Calculated\nchemical purity exceeds 99.8% (external standard method), with corresponding computational\ndetails supplemented in the experimental section “S1.2 Purity and Characterization of DATNBI.”\nTo further address the reviewer’s comment and offer a more comprehensive purity assessment,\nwe\nhave now added the Nuclear Magnetic Resonance (NMR) characterization data. The NMR spectra\nwere acquired on a Bruker Avance NEO 400 MHz spectrometer using DMSO‑d6 as the solvent. In\nthe 13C NMR spectra of AEM-DATNBI, the chemical shifts of the imidazole ring were observed\nat 135.7, 134.3, and 131.6 ppm, while the corresponding 1H NMR signal appeared at 6.98 ppm.\nThese values are consistent with those reported for CEM-DATNBI1‑2. The 1H and 13C NMR\n)%(\ntnetnoc\nnoitaleR\n1\n1\n2\n0\n8\n6\n4\n2\n0\n0\n0\n0\n0\n0\n4\n2\n1\n-\nN\n8\n7\n6 %\n2\n%\n%\n%\nA\nO\nT\n/C\nN\nO\nB\nN O\nC\nC\nE\nO\nM\n4\n1\n2\n1\n-\n5\n6\n6\n%\n%\n%\n%\nA\nH\nT\nO\nB I\nspectra of DATNBI are now provided in Supplementary Figures S12.\n7×106\ny=8542429.87x-156647.29\n6×106 R2=0.992\n)\nn\nim\n5×106\n*\nV\nm\n(\na\n4×106\ne\nr\na\nk 3×106\na\ne\nP\n2×106\n1×106\n0.20.2 0.3 0.4 0.5 0.6 0.7 0.80.9\nConcentration (mg ml-1)\nFig. S12. The regression analysis of the peak area of DATNAI versus its’ concentration\nTable S2. The retention time and peak area of CEM-DATNBI and AEM-DATNBI\nName Retention time Peak area Actual concentration Theoretical\n(min) (mV min) (mg ml-1) concentration (mg ml-1)\nCEM- 11.79 1521490 0.200 -\nDATNBI-1\nCEM- 11.81 4151874 0.496 -\nDATNBI-2\nCEM- 11.82 5495560 0.664 -\nDATNBI-3\nCEM- 11.83 6331523 0.762 -\nDATNBI-4\nAEM- 11.84 2658248 0.329 0.330\nDATNBI\nFigure S13. (a) 1C NMR spectra of AEM-DATNBI and CEM-DATNBI, (b) 1H NMR spectra of\nAEM-DATNBI and CEM-DATNBI.\n1. Ma, Q., Lu, H., Liao, L., Fan, G. & Huang, J. One-Pot Synthesis, Crystal Structure, and\nThermal Decomposition Behavior of 1,1ʹ-Diamino-4,4ʹ,5,5ʹ-Tetranitro-2,2ʹ-Biimidazole. J. Energ.\nMater. 35, 239–249 (2017).\n2. Yin, P., He, C. & Shreeve, J. M. Fully C/N‐polynitro‐functionalized 2,2′‐biimidazole\nderivatives as nitrogen‐ and oxygen‐rich energetic salts. Chem. – Eur. J. 22, 2108–2113 (2016).\n6. Reference 54 does not mention about any BAM method. A brief description of IS and FS\ndetermination to be included in the supporting information.\nResponse: We sincerely thank the reviewer for highlighting these two important points. Please\nfind our responses below.\nCorrection of Reference 54: We apologize for the error in citation. The reviewer is correct that\nReference 54 was not appropriate for the BAM method. We have now removed the incorrect\nreference and cited the proper, standard reference that describes the BAM friction sensitivity test.\nThis reference is now included as [New Reference 60] in the revised manuscript on page.\nInclusion of FS and IS Determination Description: Following the reviewer's excellent suggestion,\nwe have added a new section in the Supporting Information titled “S1.1 Experimental Methods for\nImpact Sensitivity (IS) and Friction Sensitivity (FS) Testing.”\nThis section provides a concise description of the standardized testing procedures we employed:\nFriction sensitivity was evaluated using a BAM friction sensitivity tester following the procedure\ndescribed in the UN Transport of Dangerous Goods, Manual of Tests and Criteria.\nImpact Sensitivity (IS): The test was performed using a BAM Fallhammer apparatus according to\nthe UN Manual of Tests and Criteria. A 40 mm³ sample was taken using a cylindrical measure (3.7\nmm diameter × 3.7 mm) and enclosed in an impact device consisting of two coaxial steel cylinders\nguided within a hollow cylindrical steel ring. A weight was dropped from progressively adjusted\nheights onto the upper platen to apply impact energy, until either decomposition or no reaction\nwas observed. At this energy level, the test was repeated six times. If no explosion occurred in any\nof the six trials, the corresponding impact energy was recorded as the minimum impact energy,\nexpressed in J.\nFriction Sensitivity (IS): The test was conducted using a BAM friction sensitivity apparatus\nfollowing the same standard. For our powdered sample, a quantity of approximately 10 mm³ was\ntaken using a cylindrical measure (2.3 mm diameter × 2.4 mm deep) and placed on the plate. The\nfirmly clamped porcelain peg was carefully lowered onto the sample. The loading arm was then\nloaded with the required weights. The switch was operated to move the porcelain plate relative to\nthe stationary porcelain peg. Care was taken to ensure the peg rested fully on the sample, that\nthere is enough of the substance to come under the peg when the porcelain plate moves in front of\nthe peg. The friction sensitivity was reported as the lowest load in Newtons (N) at which ignition,\nexplosion, or a positive reaction (such as audible crackling, sparking, or decomposition) was\nobserved in at least one out of six trials.\nResponse to Reviewers' Comments\nWe sincerely appreciate the editors and reviewers for their time and valuable comments on\nour manuscript. We are delighted that the reviewers found our previous revisions have\nsubstantially improved the manuscript. Following the remaining comments and editorial\nsuggestions, we have conducted comprehensive revisions to fully address all concerns. The\npoint-by-point responses are detailed below.\nReviewer #3 (Remarks to the Author):\nWe sincerely thank you for your thorough review of the revised manuscript and for your valuable\nsuggestions. These recommendations have further enhanced the scientific rigor and clarity of\nexpression in our paper. We have carefully revised the manuscript according to each of your\nsuggestions. The specific modifications are as follows:\n(1) In response to Reviewer #3, comment #4; The logic presented is generally acceptable; however,\nthe explanation requires some revision. The percentage formation of CO and CO is used to explain\n2\nthe difference in the mass of the DATNBI residue. Yet it must be noted that the total amount of\ncarbon remains the same, regardless of whether it is amorphous or crystalline. In addition, oxygen\nis readily available both from the molecule itself and from the environment (since a standard TGA\ninstrument is not sealed against oxygen ingress). Given that both CO and CO are gaseous products,\n2\nit is unclear why carbon would remain in one case but not in the other. This point requires further\nclarification.\nResponse: Thank you very much for your insightful and constructive comments. You correctly point\nout that the total amount of carbon is conserved and that oxygen is obtained from molecules and the\nexperimental environment. We agree that explaining the difference in residue mass solely by the\nratio change of gaseous products CO and CO₂ without elucidating the underlying physicochemical\nmechanism leading to solid carbon residue is indeed insufficiently clear.\nYour question touches upon a key finding in our research. Amorphous structures significantly\ninfluence the integrity of decomposition pathways by altering the local environment and diffusion\nbehavior of reaction intermediates, thereby suppressing the formation of carbon-rich solid residues\nthat are difficult to oxidize. Crystalline DATNBI (CEM-DATNBI) exhibits a dense, ordered\nmolecular packing structure. During early pyrolysis, reactions may preferentially initiate at grain\nboundaries or defects. Partially oxidized intermediates (e.g., CO precursors) generated are restricted\nfrom diffusing out of the dense crystalline structure. These carbon-rich intermediates, “trapped”\nwithin or on the crystal surface, cannot fully contact oxygen for deep oxidation. Consequently, they\nare more prone to side reactions like polymerization and aromatization, ultimately forming highly\nthermally stable, non-volatile carbonaceous solid residues that resist further gasification. This\nexplains the incomplete mass loss (77.3%) and relatively high CO yield. In contrast, amorphous\nDATNBI (AEM-DATNBI) exhibits a structure characterized by long-range disorder and large free\nvolume. This structure provides more unobstructed pathways for the diffusion of reactants and\nintermediates. Consequently, intermediates generated during decomposition can rapidly diffuse and\nmix thoroughly with oxygen atoms originating from within the molecules, enabling a more complete\noxidation reaction. This significantly suppresses the formation of carbon-rich solid residues,\nresulting in final reaction products consisting almost entirely of gaseous N₂O, CO₂, H₂O, and other\ncomponents. Consequently, near-complete mass loss (97.4%) is achieved.\nIn short, the difference in residue mass primarily stems from the amorphous structure inhibiting the\nformation of solid carbon residues, rather than simply altering the gas-phase ratio of CO and CO₂.\nThe reduced CO yield results from more complete oxidation, not as a direct cause of decreased\nresidues; the fundamental reason lies in the reaction pathway shifting toward more thorough\noxidation, thereby avoiding the generation of solid carbon.\nWe believe that the above modifications and clarifications have fully addressed your concerns and\nprovide a more in-depth and logically consistent explanation of the relevant mechanisms. Thank\nyou once again for helping us enhance the quality of our paper.\n(2) Though the work is novel over emphasis as novel energetic material such as \"The emergence of\namorphous energetic materials pioneers an entirely new, unexplored research frontier in explosives\nscience. Its significance extends far beyond the discovery of a novel material, representing a\nparadigm shift in research and a transformative future for the industry.\" may be avoided\nResponse: We fully accept the reviewers' suggestions and have systematically revised the entire\nmanuscript according to their feedback and the journal's formatting requirements. We have removed\nall subjective and exaggerated language throughout the manuscript. The example sentence on line\n95 has been revised to: “The emergence of amorphous energetic materials pioneers an unexplored\nresearch area in explosives science. Its significance extends beyond the discovery of a new material,\nrepresenting a promising direction for research and industry.”\nOn line 218 has been revised to: “While AEM-DATNBI has achieved a degree of structural stability,\nfurther improvements are necessary to ensure that amorphous energetic materials remain stablenunder complex and variable application conditions.”\nOn line 245 has been revised to: “AEM-DATNBI exhibits a low mechanical sensitivity, which can\nbe ascribed to its uniform internal structure and low-defect characteristics. These features reduce\nhot-spot nucleation in amorphous matrix.”\nWe have ensured that the tone throughout the text remains scientific and neutral, focusing on\nreporting data, analyzing results, and explaining mechanisms.\n(3) Title doesn't read smooth need to be refined.\nResponse: Thank you for bringing this to our attention. We have revised the title in accordance with\nthe specific recommendations provided by the journal editor in the Author Checklist: “Entropy-\nMediated Solidification Stabilizes and Enhances Energetic Release in Amorphous Energetic\nMaterials.” The revised title has been updated in all manuscript files."}]

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