bluuebunny/crossref_metadata_2025_split huggingface dataset:
(Invited) On the EIS Response of Composite Insertion Electrodes – Toward a Better Understanding of Porous Electrodes
Authors: Gruet David , Delobel Bruno , Lucas Ivan , Sicsic David , Vivier Vincent 
Published: February 2020

Electrochemical Impedance Spectroscopy (EIS) is a powerful tool to assess and understand the degradation of Li-ion battery (LIB) performances during operation (upon charge and discharge cycles). The full interpretation of EIS spectra of LIB can be however tedious because these systems are composed of porous electrodes and complex electrolyte. Moreover, side reactions, such as the formation of an insulating layer around the particles of the porous electrodes, can occur in battery operation modifying the impedance response.
A way to improve the interpretation of impedance data of LIB is the use of modeling. Most of the time, data interpretation is limited to the use of Electrical Equivalent Circuits (EEC) but the link between EEC and the physical processes involved in the system is ambiguous and difficult to establish. However, in the 60’s, Newman et al. [1] devised a model for porous battery electrodes. Their model describes the whole battery system thanks to equations that are directly related to the physical phenomena occurring in the composite electrodes. This model is still widely used in the battery field to simulate galvanostatic charge and discharge. Based on their work, and inspiring by works already done on modeling of EIS [2], it is possible to devise a model by linearizing all the equations [3]. The model obtained can then be directly connected to the physical phenomena occurring inside the porous electrodes which will greatly help to interpret EIS spectra.
In this work, we developed an analytical solution for the electrochemical impedance of a porous electrode composed of spherical intercalation particles in contact with concentrated electrolyte. The proposed model which is based on the concentrated solution theory but which also considers kinetics limitations and both solution-phase and solid-phase diffusion limitations, can predict the EIS response of a porous electrode at any state of charge using a limited set of parameters. Moreover, the developed model can predict the optimal porosity of the electrode to be targeted during the manufacturing process for the best cycling performances depending on the composition of the electrode (volume fractions of active material, binder, and conductive agent).
(1) Newman, J.S.; Tobias, C.W. Journal of the Electrochemical Society
1962
, 109(12), page 1183-1191.
(2) Meyers, J.P. et al. ; Journal of the Electrochemical Society
2000
, 147(8), page 2930-2940.
(3) Huang, J.; Zhang, J.B. Journal of the Electrochemical Society
2016
, 163(9), page A1983-A2000.
3D Porous Carbon Networks Decorated Metal-Organic Framworks and Their Derivates for Energy Storage
Authors: Deng Xiaoyang , Ma Liying , Zhao Naiqin 
Published: February 2020

Metal organic frameworks (MOFs) assembled by metal ions with organic linkers are one of the most promising porous crystalline materials due to their tunable porosity, wide varieties, large specific surface area and excellent physical and chemical performance.[1] But the instability and electron conductivity of most MOFs are poor. The micropore structures restrain the infiltration of electrolyte and the transport of mass ions in electrochemical process, which hinder the application of MOFs in energy storage as a result.[2,3]

Recently, the rational structure design has been demonstrated as an effective path to circumvent the above-mentioned drawbacks. Especially, 3D carbon network (3DCN) has been employed as a conventional substrate to fabricate the composites because of its high electrical conductivity, controllable pore-size distribution and interconnected porous network.
Herein, we report a facile nanoconfined strategy to prepare the MOF-3DCN composite with Ball-in-Cage nanostructure. The unique “Cage” frame not only controls the ZIF-67 particle size, but also ensures a high electron conductivity of the entire structure, which displays high electrochemical performance in supercapacitor. It can be transformed into metal oxide or sulfide/carbon composites through thermal treatment methods. The MOF-derived materials show great storage performances for lithium-ion batteries as well. Furthermore, another 3D carbon network was served as the matrix for the ZIF-8 nanoparticles fabrication. A spider-web-like carbon pattern formed on 3DCN surface enhances the mass-transfer ability and takes the advantages of ZIF-derived carbon, which shows great potential in the electrolyte-based energy storage applications.

References

Song, D.;Qi-Long, Z.; Qiang, X.: Nanomaterials derived from metal–organic frameworks. Nature Reviews Materials 3, 17075 (2017).

Wu, H. B.;Lou, X. W. D.: Metal-organic frameworks and their derived materials for electrochemical energy storage and conversion: Promises and challenges. Science Advances 3, 9252 (2017).

Ke, C.;Zhenhua, S.; Ruopian, F.; Ying, S.; Hui-Ming, C.; Feng, L.: Metal-Organic Frameworks (MOFs)-Derived Nitrogen-Doped Porous Carbon Anchored on Graphene with Multifunctional Effects for Lithium-Sulfur Batteries. Advanced Functional Materials. 1707592 (2018).
The Inductive and Capacitive Characteristics of Carbonate-Derived Carbons
Authors: Hughes Matthew , Allen Jessica A , Donne Scott W 
Published: February 2020

Due to the increasing modern dependence on electronic devices, the production of carbon materials for supercapacitive and battery-based applications is an area of current research and innovation. It has been known for a considerable time that carbons can be formed through the electrolytic reduction of molten carbonate salts [1], however, little research has been put into in-depth understanding of the electrochemical characteristics of these materials. Electrochemical impedance spectroscopy can tell us a lot about the suitability of these materials for supercapacitive applications. This research investigates how the characteristics of carbons derived through molten carbonate reduction change based on synthesis conditions, with a particular focus being placed on the inductive and capacitive behaviour of the materials and on how inductances arise (Figure 1 (i)). This is done through the application of equivalent circuit modelling (Figure 1 (ii)) to cells constructed from synthesised and activated carbons, and the subsequent mathematical modelling of the system using complex non-linear least squared error curve fitting (CNLS) based on the interior-point algorithm in the MATLAB program. The frequency-dependant capacitance of the materials (Figure 1 (iii)) is reported and used as a point of comparison. Optimal carbon synthesis conditions of 500°C or low deposition current densities of 0.15 A/cm2 have been found to both reduce inductive behaviour, and to produce carbons with capacitances as high as 160 F/g, close to 90% of that of the examined activated carbon.
[1] Hughes, M.A., J.A. Allen, and S.W. Donne, Carbonate Reduction and the Properties and Applications of Carbon Formed Through Electrochemical Deposition in Molten Carbonates: A Review. Electrochimica Acta, 2015. 176: p. 1511-1521.

Figure 1
Carbon Quantum Dots in Novel Photosystem I-Based Photovoltaics for Enhanced Photocurrent
Authors: Stachurski Christopher , Jennings G. Kane , Cliffel David E. 
Published: February 2020

Although modern photovoltaics have reached internal quantum efficiencies greater than 50%, it has come at the expense of requiring extensive synthetic conditions and materials harmful to the environment. As an alternative, our group has turned to a class of bioinspired photovoltaics using Photosystem I (PSI), a robust membrane protein complex found in plants, to generate photocurrent when interfaced with semiconductive materials. Although functional PSI devices have been made using a variety of materials (silicon wafers, nanoporous gold, graphene) they often require extensive processing of the materials and harsh experimental conditions. Furthermore, the observed photocurrent densities tend to suffer from poor contact at the protein-electrode interface.
In this work, an emerging class of carbon semiconductors, carbon quantum dots (CQDs), will be synthesized to promote charge separation in PSI photovoltaic cells. Through a facile, one-step solvothermal synthesis, CQDs electronically compatible with PSI can be made from common carbon precursors and novel small molecule dopant sources, cutting the cost and environmental impact of our devices. Following purification, the as produced CQDs exhibit tunable band energetics as a result of varied synthetic conditions allowing for precise band alignment. Thanks to their small size and modifiable carbon surface, CQDs are compatible with a number of coupling strategies allowing for a more uniform PSI-CQD interface, potentially enhancing the observed photocurrent densities. This study will open the door to a low-cost, organic photovoltaic whose fabrication could generate significantly higher photocurrent, easily be scaled-up or used in non-laboratory settings.
(Invited) Water-Soluble Biopolyimides with Ultrahigh Performances
Authors: Kaneko Tatsuo , Dwivedi Sumant , Takada Kenji 
Published: February 2020

Bioplastics are indispensable for establishment of green-sustainable society. Conventional bioplastics composed of aliphatic polymers like poly(lactic acid)s are successfully circulated as a specific field. In order to widen the field of bioplastics, aromatic bio-based polymers are required. Under this background, we have prepared aromatic biopolymers derived from exotic biochemicals with rigid backbones [1-3]. Here we used 4-aminocinnamic acid (4ACA) which was bioavailable by a microorganismal genetic-engineering. The photodimer of 4ACA was successively prepared as a bio-derived aromatic diamine via [2+2] cycloaddition in the solid state with a perfect conversion degree by illumination of UV-LED. The biodianilines were polymerized with diisocyanates, diacids, and tetraacid dianhydrides to produce aromatic polymers such as polyureas, polyamides, and polyimides, respectively. Almost bio-based polymers prepared here showed a high transparency, high heat-resistance, and high mechanical strength. Especially the biopolyamide showed extremely-high fracture strength around 400 MPa as high as those of high-tensile steels, in spite of amorphous structure [3]. The optimization of the biopolyimide structure gave the fantastic properties of ultrahigh toughness comparable with those of spider silks. On the other hand, the aromatic polyimides derived from the bio-photodimer with cyclobutanetetracarboxylic dianhydrides showed a good thermomechanical performance as well as low density around 1.05-1.28 g/cm3, and additionally showed a high transparency [2,4]. These thermal/mechanical performances are higher than those of conventional transparent polymers, in spite of limited molecular design by bio-based molecules. Additionally we found that the water-solubility was imparted in polyimide materials when the side carboxylate groups were ionized, which was a surprizing phenomenon because the aromatic polyimides are generally insoluble in any solvents.
Acknowledgement: The authors gratefully acknowledges Grant-in-Aid supports from ALCA (5100270) of JST, Japan and from Scientific Research (B) (15H03864) of MEXT, Japan.
References:
[1] T. Kaneko, et al., Nature Mater., 5, 996-970 (2006)
[2] P. Suvannasara, T. Kaneko et al. Macromolecules, 47, 1586-1593 (2014)
[3] S. Tateyama, T. Kaneko et al. Macromolecules, 49, 3336-3342 (2016)
[4] G. Liou, T. Kaneko, et al. Nanoscale, 8, 12793 (2016)

Figure 1. Typical structure of biopolyimide prepared from microbial aromatics

Figure 1
(Invited) Instantly Formative Hydrogels with Super-Low Polymeric Component
Authors: Sakai Takamasa 
Published: February 2020

Hydrogels are water-filled materials with characteristics similar to those of biological soft tissues and have broad application as biomaterials. However, the safety of hydrogels is difficult to guarantee throughout the full life cycle in vivo due to the inevitability of degradation-induced swelling. Indeed, the swelling pressure exerted by conventional hydrogels is sufficiently large to cause severe adverse reactions to surrounding tissues. In this respect, we report here a new class of in situ forming hydrogels that guarantee safety throughout the full life cycle. The oligo-TetraPEG hydrogel has an extremely high water content and a polymer content of only 4.0 g/L, resulting in an exceptionally low swelling pressure.
The oligo-TetraPEG hydrogel was successfully injected and gelled inside a living body within a clinically relevant manipulation time and little cytotoxicity. The oligo-TetraPEG hydrogel exhibited an appropriate stiffness, similar to that of soft tissue, with extremely low swelling pressure thus being compatible with living tissues. The oligo-TetraPEG hydrogel functioned as an artificial vitreous body for over a year without any adverse effects, and was effective for treating retinal detachment as an intravitreous tamponade material．The present concept provides new guidance for the safety of biomaterials in vivo.

Figure 1
(Invited) A Thermo-Responsive Cationic Comb-Type Copolymer Enhances Membrane Permeabilizing Activity of an Amphiphilic Peptide
Authors: Masuda Tsukuru , Shimada Naohiko , Maruyama Atsushi 
Published: February 2020

Amphiphilic peptides are great focus owing to potential applications including drug delivery systems and antimicrobials. E5 peptide, one of amphiphilic peptides, forms amphiphilic α-helix at low pH, and exhibits membrane permeabilizing activity.1,2) However, the activity of E5 peptide is low attributed to low solubility in aqueous media. In the previous paper, we showed that the cationic comb-type copolymer, poly(allylamine)-graft-dextrane (PAA-g-Dex) formed soluble inter-polyelectrolyte complex (sIPEC) with E5 peptide at both low and natural pH, and E5/PAA-g-Dex exhibited strong membrane disruptive activity.3) In this study, we designed a novel comb-type cationic copolymer composed of a PAA main chain and thermoresponsive poly(N-isopropylacrylamide) graft chains (PAA-g-PNIPAAm). We hypothesized that the thermoresponsive hydrophilic/hydrophobic transition of the grafted polymer would regulate the membrane disruption activity of E5 peptide.
The target copolymer was prepared by activators regenerated by electron transfer atom transfer radical polymerization (ARGET ATRP). The ratio of AA units to Initiator to NIPAAm units was estimated to be 100:9:421 by 1H NMR. Thus, the number-averaged molecular weight (M
n) of PNIPAAm and the PNIPAAm contents were 1.0 × 104 and 94.3 wt %, respectively. Circular dichroism (CD) spectra measurement revealed that PAA-g-PNIPAAm formed sIPEC with E5 peptide, resulting in α-helix formation of E5 peptide. Furthermore, the complex formation of E5 and PAA-g-PNIPAAm was investigated by measuring the fluorescence spectra of triptophan residure in E5 peptide. From these investigations, we found that the interaction between E5 peptide and PAA-g-PNIPAAm at 35 °C (above LCST) was stronger than that at 25 °C (below LCST). These results suggest that the hydrophobicity of the environment around the cationic polymer chain influences complex formation. E5 peptide in the presence of PAA-g-PNIPAAm induced the leakage from liposomes, whereas E5 peptide alone did not. Importantly, E5/PAA-g-PNIPAAm induced more significant leakage at 35 °C than at 25 °C. Thus, membrane disruptive activity of E5/PAA-g-PNIPAAm sIPEC was regulated in response to temperature coupled with the phase transition of the thermo-responsive grafted chain.4)

References: 1) M. Murata, et al., Ohnishi, J. Biol. Chem.
1991, 266, 14353. 2) M. Murata, et al., Biophys. J. 1993, 64, 724. 3) N. Shimada et al., J. Controlled Release
2015, 218, 45. 4) T. Masuda et al., Biomacromolecules
2018, 19, 1333.

Figure 1
(Invited) Designed Polymers for Antifouling Surfaces
Authors: Ando Tsuyoshi , Totani Masayasu , Yamamoto Ikuo 
Published: February 2020

There is a strong demand for antifouling surface. To create such antifouling surface, there are some approaches such as chemical reaction at the surface, coatings, internal additives, etc. We are developing polymers that can modify the surface property by easy treatments based on precise design and synthesis of the polymers.
Biomedical synthetic materials, such as poly(ethylene terephthalate) (PET) and polypropylene (PP), are prone to adhesion of proteins, cells, and bacteria, causing functional failures in implants, artificial organs, catheters, and diagnostic devices, and increasing the risk of secondary infections. One of the promising answers is a hydrophilic polymer brush surface on which many polymer chains are connected in high density to inhibit adsorption of proteins and following adhesion of related biomolecules and cells. Such high density polymer brush is usually built by surface-initiated living radical polymerization through several chemical steps and polymers applied for medical devices are rather inert to chemical modification than inorganic materials. We thus created a new star shaped heteroarm polymer consisting of hydrophilic chains, as an antifouling block, and hydrophobic chains, as a substrate attaching block, for a biocompatible coating material, which is supposed to form polymer brush-like structure by simple coating procedure. The coating surface exhibited very good resistance to adhesion of platelets, bacteria, fibroblasts, and proteins although the corresponding linear polymer exhibited moderate resistance. This result indicates utilization of unique architecture of the star polymer is effective for building condensed polymer brush structure at the surface.
Perfluoroalkyl group-containing polymer shows water/oil repellency. Although long perfluoroalkyl groups (longer than C8) exhibit high repellency, they can not be employed because of the environmental reason, nowadays. Shorter perfluoroalkyl groups (less than C8) give less effect to environment but they have less repellency. We thud designed block copolymers consisting of fluorine and non-fluorine containing monomers and evaluated the sequence effects as an internal additive to PP resin to improve oil repellency. By controlling fluorinated/non-fluorinated monomer sequence, the oil repellency of the fluorinated polymer-added polypropylene (PP) was dramatically improved compared to that modified with the randomly sequenced fluoropolymer. For instance, random copolymer consisting of 2-(perfluorohexyl)ethyl methacrylate (C6FMA) and stearyl methacrylate (StMA) gave slightly higher contact angle (13º) than that of non-additive PP (6º). Compared to the random copolymer, the diblock and triblock copolymer lead much higher contact angles (23º and 38º, respectively) when only 1wt% of the fluoropolymer was mixed into PP. This result indicates sequence regulation of fluorinated/non-fluorinated monomer in the fluoropolymer is effective to concentrate fluorine groups at the resin surface resulting in improvement of water/oil repellency.
Development of Physical Property Measuring Device for 3D Food Printer Gel
Authors: Ishigaki Ryo , Kodama Mai , Khosla Ajit , Kawakami Masaru , Furukawa Hidemitsu 
Published: February 2020

In recent years, research and development of 3D food printers have been actively conducted, and it is expected to change the future food problems immensely and the way of food manufacturing and processing.
In the Food Layer Manufacturing(FLM) 3D food printer, the molding conditions must be set for physical properties of the each material. In the previous study, researches were conducted on the relationship between viscosity and molding conditions by rheometer or viscometer, and it is reported that the modeling accuracy improves as viscosity increases. However, since it is difficult to use a rheometer or a viscometer at each household, a simple physical property measuring device is necessary. Therefore, in this study, we will investigate whether the shaping conditions can be determined from the concentric circle spreading out of the container after vibrating the gel contained in the cylindrical container with the diaphragm. Also, We will confirm whether or not it is possible to measure simple kinematic viscosity of a high viscosity material by checking the presence or absence of concentric circle spread and viscosity relationship.
Preparation of Multiple Parallel Protein-polysaccharide Hybrid Gel Filaments Under Shear
Authors: Takayama Yuriko , Kato Norihiro 
Published: February 2020

Fabrication of anisotropic gel with characteristic structures has been reported using a flow system with three dimensional microfluidic devices. Such gel structures are mainly achieved by design and preparation of the microchannel for flowing pre-gel solution. In this research, we propose a method for preparing multiple parallel gel filaments by controlling viscoelastic properties of polymer assembly as the fluid of microfluidic devices.
To promote the formation of heterogeneous assembly of different types of macromolecules, an aqueous two-phase separation (ATPS) technique was utilized. Two layers of aqueous solutions appear when the ATPS conditions including ionic strength, temperature, and solute concentration in certain combinations of two components are satisfied. In respective phase, some solute molecules form heterogeneous assemblies because the solutes in respective phase are highly concentrated. We previously reported that the alginate (Alg) could form the assembly with polyethylene glycol (PEG) in the induced phase of Alg/PEG/NaCl system. In aqueous media, the Alg assembly has the rigid structure because diaxial linkages in a successive region of guluronic acid are stabilized by hydrogen bonds. Destruction of hydrogen bonds of Alg molecules by interaction with PEG enables deformation of Alg assembly by shear.
Gel filaments were prepared with a co-axial flow device as double glass tubes, where an inner tube (inner diameter 0.7 mm) was fixed at the insert position of the outer tube. Pre-gel solution and crosslinker solution respectively were flown to inner and outer tube using syringe pumps. The morphology of the gel filaments was observed by a scanning electron microscope.
A single thick gel filament was obtained from aqueous sodium alginate solution, whereas multiple thin gel filaments were obtained when a mixed solution of Alg and PEG under the ATPS condition. Appearance of shear-thinning behavior for the Alg-rich phase suggests that the complexation of Alg with PEG was responsible for destruction of the rigid assembly due to breaking hydrogen bonds. In this poster, the method will be applied to the protein containing system to fabricate the protein-polysaccharide hybrid filaments.