bluuebunny/crossref_metadata_2025_split huggingface dataset:
Orthogonal Multiple Click Reactions for Macromolecular Design
Authors: Durmaz Hakan , Tunca Umit 
Published: March 2022

Abstract
In this article, we first examine the classical click reactions and new members (or candidates) to the click chemistry family involving multicomponent reactions (MCRs) utilized in synthetic polymer chemistry. The pros and cons of MCRs are described in the way of click chemistry philosophy. Subsequently, updated click combinations implemented to the synthesis of macromolecular structures are presented in two tables starting from double toward multiple. Moreover, combinations of click reactions with MCRs are presented comprehensively.
NMR Spectroscopy
Authors: Spiess Hans W. 
Published: March 2022

AbstractThe function of synthetic macromolecular materials critically depends on the packing and dynamics of the components of such systems. Solid‐state NMR can provide structural information with atomic resolution and moreover can characterize the amplitude and time scale of motions over broad ranges of length and time. These movements include molecular dynamics, rotational, and translational motions of the building blocks, and also the motion of the functional species themselves, such as protons or ions. In this article, current NMR techniques are introduced and their applications illustrated by numerous examples of a broad range of synthetic macromolecular systems.
Porous Polymers by Block Copolymer Templating
Authors: Grande Daniel , Le Droumaguet Benjamin 
Published: March 2022

Abstract
The past decades have witnessed an increased attention in porous polymeric materials with controlled pore sizes and desired functionalities, due to the wide array of their applications. Organic porous materials display unique properties compared to their inorganic nanostructured counterparts, including tunable mechanical properties, facile functionalization, and low‐cost production. Engineering nanoporous polymers with tunable pore morphology and functionality, while maintaining high chemical and mechanical stability, still constitutes a major challenge.
Interestingly, block copolymers develop well‐defined equilibrium domain morphologies. Accordingly, they can arguably be considered as ideal nanostructured precursors toward ordered nanoporous frameworks. In this regard, the selective removal of the sacrificial minority block in self‐organized block copolymers with at least two components of contrasted degradability has proven to be a robust approach toward miscellaneous nanoporous polymeric materials with controlled porosity. Alternatively, ongoing research addresses the development of more efficient and environmentally benign degradation strategies. The insertion of an easily cleavable function at the junction between the alien blocks of diblock copolymers represents a promising route, since it enables site‐specific scission between both the blocks, without requiring etching of the entire sacrificial segment. Lastly, by introducing specific functional moieties at the junction between the degradable block and the stable one of the semidegradable block copolymers, pore surface functionalization can readily be achieved.
Separation of Polymers by Chromatography
Authors: Chang Taihyun 
Published: March 2022

Abstract
While mother nature can produce uniform macromolecules as found in many biological systems, man‐made polymers are hardly homogeneous. Synthetic polymers are usually complex mixtures of molecules differing in various molecular characteristics such as molecular weight (MW), chemical composition, functionality, microstructure, and chain architecture. For precise characterization of polymers, the multivariate distributions in all these molecular characteristics need to be measured, which is an extremely difficult task, if not impossible. In practice, however, it is often sufficient to analyze a limited number of molecular characteristics. For the purpose, liquid chromatography is the most widely used method that has made a remarkable progress during the last several decades in both instrumentation and understanding of the separation mechanism.
Size exclusion chromatography (SEC) has been the most widely employed chromatographic separation technique for the characterization of synthetic polymers since its inception about a half‐century ago. Compared to traditional fractionation methods of polymers, SEC is an excellent method in precision, analysis speed, required amount of a sample, etc. Nonetheless, SEC separates the polymer molecules according to the chain size that depends on not only MW but also other molecular characteristics such as composition, chain architecture, and microstructure. Therefore, for instance, SEC cannot separate nonlinear homo‐polymers according to MW or copolymers according to the composition. In contrast to SEC in which the different pore‐accessibility of macromolecules is the main separation mechanism, interaction chromatography (IC) fractionates polymers according to the interaction strength between the polymer molecules and the sorbent. In results, IC is more sensitive to the chemical nature of the polymers than SEC. By judiciously selecting the IC separation condition, it is possible to separate polymers according to specific molecular properties with higher resolution than SEC. Furthermore, one can access to the chromatographic critical condition for a given polymer system by adjusting the solute interaction strength with the sorbent until the exclusion and interaction contributions to the solute retention are exactly compensated. At the critical condition, polymers of different MW coelute. Therefore, LC at the critical condition (LCCC) can be used as a unique tool for the characterization of polymers since one can suppress the peak dispersion by MW distribution and focus on other molecular characteristics. Recently, polymer separations using two‐dimensional LC by a rational combination of SEC, IC, or LCCC have become more and more popular for the characterization of polymers with multivariate distributions. In this article, chromatographic separation methods of synthetic polymers are reviewed with an emphasis on non‐SEC methods.
Scattering From Polymer Systems
Authors: Mao Yimin , Liu Tianbo , Chu Benjamin 
Published: March 2022

AbstractLight, X‐ray, and neutron scattering techniques are complementary tools for the investigation of polymer structure and dynamics. This article introduces the working principles of static and dynamic light scattering (SLS/DLS), in combination with small‐angle X‐ray scattering and neutron scattering (SAXS/SANS), and their applications to studies of polymer structure and dynamics. General scattering theories based on momentum and energy transfer are introduced, focusing on the concepts of interference phenomenon and time correlation function. Several examples are given, including basic characterization of polymer molecular weight and weight distribution, single‐chain conformation and phase transition, hierarchical structures and aggregation kinetics, particle shape analysis, and condensed two‐phase systems. The advantages of a more comprehensive analysis by combining different scattering techniques are being emphasized. Practical aspects for choosing relevant techniques, sample preparation, and scattering background handling, etc., are briefly discussed to help the readers to effectively use those scattering techniques for studying the structure and dynamics of polymers.
Aliphatic Poly(carbonate)s: Syntheses, Structures, and Applications
Authors: Hu Lan‐fang , Zhang Cheng‐Jian , Zhang Xing‐Hong 
Published: March 2022

Abstract

Aliphatic poly(carbonate) (APC) is a kind of polymer with repeated units of [ROC(=O)O]

n

, where R is an aliphatic linker. This article introduces three universal synthetic methods to APCs, including alternating copolymerization of carbon dioxide (CO
2
) with epoxides, condensation of dialkyl carbonates with diols, condensation of CO
2
and diols (dihalides), and ring‐opening polymerization of the cyclic carbonates. The accessible catalyst systems for the copolymerization of CO
2
with epoxides are intensively discussed to understand the control of the microstructures of CO
2
‐based APCs. Special attention is paid to the metal‐free catalytic synthesis of APCs. Based on the catalysts for CO
2
‐based copolymers, a variety of di‐, tri‐, and multi‐block copolymers containing APC block are presented with the discussion of their syntheses, structures, and properties. The thermal, mechanical, biodegradable, and conductive properties of these APCs are described in detail with respect to the application.
Highly Branched Polymer Architectures: Specific Structural Features and Their Characterization
Authors: Boye Susanne , Lederer Albena , Voit Brigitte 
Published: March 2022

AbstractThis article gives a brief overview about the general synthetic procedures for branched polymers with special focus on highly branched and dendritic architectures. The characterization of these materials is not trivial, thus, special characterization techniques and approaches for their structural analysis are presented. The specific thermal properties as well as solution properties of branched polymers are discussed. The basic determination of the degree of branching, molar mass and conformation is explained in detail. Furthermore, special characterization techniques together with novel developments in branching characterization are briefly introduced. Finally, the structural features and specific analysis of novel branched structures and linear‐branched hybrids are emphasized.
Structure and Phase Behavior of Polyampholytes and Polyzwitterions
Authors: Pickett Phillip D. , Ma Yuanchi , Posey Nicholas D. , Lueckheide Michael , Prabhu Vivek M. 
Published: March 2022

AbstractPolyelectrolytes contain many units of charged moieties, often as either anionic or cationic. However, when a polymer comprises both anionic and cationic monomers, the result is a polyampholyte. Polyzwitterions are a type of polyampholyte that contain pairs of opposite charges within each monomer unit, ultimately leading to charge neutrality across the entire polymer structure. These special classes of ion‐containing polymers have many applications enabled by advances in synthesis. This article discusses the unique solution‐responsive behaviors of these ion‐containing polymers and how their chemistry is used to alter structure–property relationships.
Nanoparticle Transport Through Polymers and Along Interfaces
Authors: Boyle Michael J. , Maguire Shawn M. , Rose Katie A. , Lee Daeyeon , Composto Russell J. 
Published: March 2022

AbstractTransport of nanoparticles has received increasing attention for both fundamental interest to test prevailing models as well as practical interest in separations and self‐healing applications. Methods for measuring particle dynamics are briefly reviewed to orient the reader to different methodologies. The transport of nanoparticles through polymer melts, solutions, and cross‐linked networks is described with emphasis on systems where the nanoparticle is on the length scale of the defining structure including the tube size, correlation length, and mesh size, respectively. Because nanoparticles can interact with the different mediums, the interactions between nanoparticles and polymer and the subsequent impacts on dynamics are described. The transport of particles at liquid–solid (polymer brush) interfaces is addressed due to growing interest in applications ranging from understanding dynamics in porous media to the translocation of DNA. Both hard particles and polymer grafted particles (soft particles) are described. The objective of this article is to provide the reader with fundamental descriptions of phenomena while reviewing the current state of understanding. Further directions will leverage advances in inorganic chemistry to prepare monodisperse, functional nanoparticles as well as polymer chemistry to create novel media, such as networks with monodisperse mesh size.
Tailoring Charged Block Copolymer Architecture for Performance
Authors: White Benjamin T. , Liu Boer , Drummey Kevin J. , Chen Xi , Long Timothy E. 
Published: March 2022

AbstractCharged block copolymers (BCPs) find use in numerous applications spanning from gene delivery to electromechanical transducers. Recent advances in polymer synthesis have provided researchers with the necessary tools to study the properties of a wide variety of BCPs bearing cationic and anionic substituents. Controlling the architecture of these charged BCPs plays a key role in tailoring their performances in the desired application. Likewise, the polymer morphology significantly affects ion transport and thermomechanical properties of the charged BCP. This article aims to compare the structure–property relationships in charged BCPs across a variety of different polymer architectures including linear, branched, segmented, and multiply charged BCPs with a focus on tailoring properties for specific applications. Linear BCPs comprise of diblock, triblock, and multiblock copolymers. Diblocks frequently serve as micelles for drug delivery while triblocks, multiblocks, and segmented BCPs act as ion exchange membranes for transducers and fuel cells. The section on branched BCPs discusses polymer brushes, stars, micelles, and cross‐linked networks. The final section describes synthetic routes toward synthesizing multiply charged monomers and polymers while also emphasizing the challenges and benefits associated with these materials.
New Stuff in Old Places: Light Microscopy of Polymers
Authors: Srinivasarao Mohan 
Published: March 2022

AbstractLight microscopy, with a history of over 400 years, continues to be useful for the natural sciences. It has played a crucial role in the physical and biological sciences, from providing evidence for the existence of atoms to resolving cells at very high resolution. In this article, we have taken a broad view of light microscopy, in its various forms to provide physical information that helps understand the structure and perhaps, the function of, certain materials, in particular polymers, liquid crystals, and beetle exocuticles, among others. We illustrate the information that can be gleaned by polarized light microscopy studies of semicrystalline polymers and liquid crystals. We also demonstrate that polarized light microscopy is an indispensable tool in studying anisotropic structures. We illustrate how optical sectioning microscopy, namely laser scanning confocal microscopy, is useful in studying diffusion as well as analyzing the structure of jewel beetle exocuticles, and providing the elusive director configuration in three‐dimension for a liquid crystal. Finally, we demonstrate a technique based on total internal reflection to probe the topography of polymeric surfaces. In doing so, we have illustrated the rich history of light microscopy and the elegance of Ernst Abbe's work dealing with the resolution that is attainable by far‐field light microscopy.
Acute epileptiform abnormalities are the primary predictors of post‐stroke epilepsy: a matched, case–control study
Authors: Punia Vineet , Ellison Lisa , Bena Jim , Chandan Pradeep , Sivaraju Adithya , George Pravin , Newey Christopher R. , Hantus Stephen 
Published: March 2022

AbstractStroke patients who underwent continuous EEG (cEEG) monitoring within 7 days of presentation and developed post‐stroke epilepsy (PSE; cases, n = 36) were matched (1:2 ratio) by age and follow‐up duration with ones who did not (controls, n = 72). Variables significant on univariable analysis [hypertension, smoking, hemorrhagic conversion, pre‐cEEG convulsive seizures, and epileptiform abnormalities (EAs)] were included in the multivariable logistic model and only the presence of EAs on EEG remained significant PSE predictor [OR = 11.9 (1.75–491.6)]. With acute EAs independently predicting PSE development, accounting for their presence may help to tailor post‐acute symptomatic seizure management and aid anti‐epileptogenesis therapy trials.
H2S Involved Photocatalytic System: A Novel Syngas Production Strategy by Boosting the Photoreduction of CO2 While Recovering Hydrogen from the Environmental Toxicant
Authors: Li Kai , Cai Yanming , Yang Xiaohan , Wang Shuang , Teng Chao , Tian Ye , Min Qianhao , Zhu Wenlei 
Published: March 2022

AbstractSimultaneous treatment of CO2 and H2S by photocatalytic technology is of great significance in mitigating the greenhouse effect and environmental hazards, while producing valuable solar fuels at the same time. In this study, well‐defined CdS/TiO2:Cu hollow spheres with highly dispersed heterointerfaces are successfully constructed for photoreduction of CO2 in presence of in situ generated H2S. Benefiting from the consumption of photo‐generated holes (h+) and large production of protons by H2S decomposition, the generation rates of CO (781.3 µmol·g−1∙h−1, accounting for 94.9 v/v% of CO2 reduction products) and H2 (5875.1 µmol·g−1∙h−1) increased significantly, which are 1.4 and 68.9 times higher than that of the system without H2S, respectively. Moreover, the remediation of photocorroded CdS by H2S prolonged the service life of the heterojunction, and maintained a CO generation rate of 96.8% after 4 cycles with or without H2S. Notably, as a potential syngas production strategy, by adjusting the initial concentration of Na2S, the ratio of CO and H2 is controlled from 1.07 to 7.21 to fulfill the demands of different chemical synthesis. This strategy opens up a new horizon for the combination of energy photocatalysis and environmental photocatalysis, which has great research and application prospects.
Multifunctional Superelastic, Superhydrophilic, and Ultralight Nanocellulose‐Based Composite Carbon Aerogels for Compressive Supercapacitor and Strain Sensor
Authors: Liu Huayu , Xu Ting , Cai Chenyang , Liu Kun , Liu Wei , Zhang Meng , Du Haishun , Si Chuanling , Zhang Kai 
Published: March 2022

AbstractDeveloping superelastic and superhydrophilic carbon aerogels with intriguing mechanical properties is urgently desired for achieving promising performances in highly compressive supercapacitors and strain sensors. Herein, based on synergistic hydrogen bonding, electrostatic interaction, and π–π interaction within regularly arranged layered porous structures, conductive carbon aerogels with cellulose nanofibrils (CNF), carbon nanotubes (CNT) and reduced graphene oxide (RGO) are developed via bidirectional freezing and subsequent annealing. Benefiting from the porous architecture and high surface roughness, CNF/CNT/RGO carbon aerogels exhibit ultralow density (2.64 mg cm–3) and superhydrophilicity (water contact angle ≈0° at 106 ms). The honeycomb‐like ordered porous structure can efficiently transfer stress in the entire microstructure, thereby endowing carbon aerogels with high compressibility and extraordinary fatigue resistance (10,000 cycles at 50% strain). These aerogels can be assembled into compressive solid‐state symmetric supercapacitors showing excellent area capacitance (109.4 mF cm–2 at 0.4 mA cm–2) and superior long cycle compression performance (88% after 5000 cycles at compressive strain of 50%). Furthermore, the aerogels reveal good linear sensitivity (S = 5.61 kPa–1) and accurately capture human bio‐signals as strain sensors. It is expected that such CNF/CNT/RGO carbon aerogels will provide a novel multifunctional platform for wearable electronics, electronic skin, and human motion monitoring.
Anomalous Thermal Decomposition Behavior of Polycrystalline LiNi0.8Mn0.1Co0.1O2 in PEO‐Based Solid Polymer Electrolyte
Authors: Yang Lufeng , Zhang Jin , Xue Weiran , Li Jizhou , Chen Rusong , Pan Hongyi , Yu Xiqian , Liu Yijin , Li Hong , Chen Liquan , Huang Xuejie 
Published: March 2022

AbstractReplacing liquid electrolytes (LEs) with polymer electrolytes has been considered a promising approach to developing next‐generation lithium‐ion batteries (LIBs) with high energy density and superior safety. Nevertheless, compared with the extensive research on the electrochemical stability of the cathode/polymer electrolyte interfaces, reports on their thermal behaviors are rare to date. Herein, this work systematically investigates the thermal stability of two typical layered oxide cathodes, LiCoO2 (LCO) and LiNi0.8Mn0.1Co0.1O2 (NMC811), with poly(ethylene oxide) (PEO) electrolyte and with carbonate LEs, respectively. It is found that the oxygen release from the cathodes plays a central role in thermal runaway. Replacing the LE with PEO electrolyte can considerably improve the thermal stability of LCO, but surprisingly, deteriorate that of NMC811. The reason is that the surface of single‐crystalline LCO particles can be effectively passivated by the PEO electrolyte during heating, but PEO cannot sufficiently passivate all the primary particles of NMC811 owing to insufficient interface wettability of PEO electrolyte within the polycrystalline secondary NMC811 particles. The findings in this work collectively formulate valuable guidance for improving the safety of polymer‐electrolyte‐based as well as other types of all‐solid‐state lithium‐ion batteries.
Manipulating the Intermolecular Interactions through Side Chain Engineering and Unilateral π‐Bridge Strategy for Efficient Small Molecular Photovoltaic Acceptor
Authors: Wang Pengchao , Bi Fuzhen , Li Yonghai , Han Chenyu , Zheng Nan , Zhang Shuai , Wang Jianxiao , Wu Yuanwei , Bao Xichang 
Published: March 2022

AbstractThanks to the development of acceptor–donor–acceptor (A–D–A) type electron acceptors, organic solar cells (OSCs) have achieved marvelous progress in recent years. However, a systematic investigation about the structure–efficiency relationship is still highly desired to better understand the working mechanisms inside a bulk heterojunction (BHJ). In this study, new acceptors with the synergistic effect of side chain and unilateral π‐bridge strategy are designed, accounting for lower energy loss, expanded absorption, modulated intermolecular interactions and BHJ morphology. As a consequence, the resultant A–D–π–A acceptor ID‐C6Ph‐ST‐4F based binary solar cell receives an impressive efficiency up to 15.36%, much greater than the A–D–A analog ID‐C6Ph‐4F (10.75%), and ranks the best among all small molecular acceptors with symmetric or asymmetric π‐bridges. The results highlight the promising manipulation of phenylalkyl side chain and unilateral π‐bridge on intermolecular interactions among acceptor molecules and interactions between donor and acceptor (D/A) molecules. Superior interactions among acceptor molecules are an essential precondition to ensure preferable molecular assembly for charge transport, and meanwhile, moderately enhanced D/A interactions are also crucial for proper phase‐separation networks with efficient exciton dissociation and charge generation.
Oxygen‐Rich Cobalt–Nitrogen–Carbon Porous Nanosheets for Bifunctional Oxygen Electrocatalysis
Authors: Zhang Wang , Xu Chen‐Hui , Zheng Han , Li Rui , Zhou Kun 
Published: March 2022

AbstractMetal–nitrogen–carbon (M–N–C) materials have attracted much interest in bifunctional oxygen‐involving electrocatalysis for rechargeable Zn–air batteries. Such M–N–C electrocatalysts with M–Nx sites show good activity for the oxygen reduction reaction (ORR) but moderate activity for the oxygen evolution reaction (OER). Herein, an oxygen‐rich M–N–C material (O–Co–N/C) with a highly porous nanosheet structure is reported as a bifunctional oxygen electrocatalyst, which is prepared by the direct pyrolysis of ultrathin CoO nanosheets decorated with zeolitic imidazolate framework‐8 nanoparticles under an inert atmosphere. Particularly, Co nanoparticles in the O–Co–N/C electrocatalyst contain both Co–Nx and Co–Ox coordination environments to provide intrinsic active sites for the ORR and OER, respectively. Furthermore, electrochemical studies show that the O–Co–N/C catalyst retains comparable ORR activity to common M–N–C materials with a half‐wave potential of 0.85 V vs the reversible hydrogen electrode and better OER activity with an overpotential of 0.29 V at the current density of 10 mA cm−2. This study provides insights into the development of effective oxygen‐involving electrocatalysts with bifunctional metal active centers coordinated by both nitrogen and oxygen atoms.