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For several decades, poly(1,2-difluoroethylene) [PVLF, −(CHFCHF)n−] had been believed to be atacticand amorphous. However, our recent study has revealed that PVLF is an atacticbut partially crystallinepolymer. In the present report, the crystal structure of PVLF, as the most important basic structural information, was determined by the quantitative analysis of 2D wide-angle X-ray diffraction (WAXD) data measured at room temperature. The two chains pass through the orthorhombic unit cell of a= 9.20 Å, b= 5.32 Å, c(chain axis) = 4.97 Å with the space group Pcam. The polymer chains take the deflected zigzag conformation of TS′TS̅′ (torsional angles, T: 180° and S′: 142°), which is contracted slightly from the fully extended all-trans form. The temperature-dependent measurement of the WAXD patterns revealed that the unit cell size increases almost linearly with temperature but shows a small deflection point at around 100 °C. This deflection corresponds to the reversible second-order phase transition between the low-temperature (LT) phase and the high-temperature (HT) phase. The molecular dynamics calculation revealed an occurrence of the thermally activated translational and torsional motion of molecular chains in the HT phase. In parallel, temperature-dependent small-angle X-ray scattering data analysis revealed that the lamellar stacking structure changes irreversibly at the transition point as a result of such thermally enhanced motions of molecular chains.

Two biodegradable polyesters, poly(butylene succinate) (PBS) and poly(butylene succinate‐co‐adipate) (PBSA), were artificially aged in a UV irradiation test chamber, and their photodegradation behaviors investigated. The attenuated total reflection (ATR) infrared (IR) spectra of the initial and UV‐aged samples revealed conformational changes in the tetramethylene sequences of the photoaged PBS and PBSA. The one‐dimensional wide‐angle X‐ray scattering (WAXS) profiles showed that the (110) d‐spacing of the α‐form crystal progressively decreased during UV aging, suggesting that the crystalline polymer chains became arranged more closely along the fiber axis. Accordingly, we conclude that PBS and PBSA transform from their TGTGTto nearly TTTTTconformations upon photoaging. The observed WAXS, small‐angle X‐ray scattering, and IR spectral data suggest that photodegradation preferentially occurs in the amorphous phase of each polymer. The less crystallizable butylene adipate co‐unit enhances the degradability of PBSA, with prolonged photooxidation leading to partial degradation of the crystalline region of the copolymer. This finding is consistent with and may be linked to the higher biodegradability of PBSA compared to PBS.

The orientation of the crystalline lattice formed as a consequence of strain-induced crystallization (SIC) was revisited for a natural rubber (NR) sheet undergoing planar elongation by being stretched in one direction while keeping the other dimension unchanged. For this purpose, two-dimensional wide-angle X-ray diffraction patterns were measured by changing the inclination angle of the incident X-ray beam to the specimen sheet. The intensity of the reflection from the (120) plane of the orthorhombic crystal increased with increasing inclination angle from the normal direction of the specimen sheet; this result indicated that the orientation of the (120) planes was parallel to the surface of the specimen sheet. Moreover, the intensity of the (200) plane reflection reached a maximum at a slightly inclined angle from the normal of the specimen surface. WAXD measurements were also conducted using different X-ray wavelengths (0.06, 0.10, and 0.15 nm) to evaluate the inclined angle of the acplane with respect to the surface of the specimen. By changing the X-ray wavelength, the distribution of reciprocal lattice points was altered such that the inclined angle of the incident X-ray beam to the specimen sheet needed to be changed to meet the diffraction condition. The inclined angle at the maximum intensity of the (200) reflection increased as a function of the X-ray wavelength. Based on this result, the preferential orientation of the acplanes was determined, whereby the acplane was not completely parallel to the surface of the specimen sheet but was slightly inclined by 6.4°. Thus, a dual orientational state was deduced. Therefore, the preferential orientation of the acplane was nearly parallel to the surface of the specimen sheet, with the inclined angle ranging from 6.4° to 19.6° within the volume of the specimen irradiated by the incident X-ray beam.

The photooxidative degradation and fragmentation behaviors of isotactic polypropylene (itPP) were simulated in laboratory after various postconditions, such as quenching, gradual cooling and drawing, using an artificial weathering machine and a blender. The crystallinity of the itPP films and orientation of the molecular chains play important roles in the photooxidation of the itPP films. Compared to quenched itPP films with the same ultraviolet (UV) exposure time, highly oriented itPP films and gradually cooled itPP films with higher crystallinity exhibited a lower rate of photooxidative degradation. To clarify the photooxidative degradation mechanism, the surface morphology, chemical structure, and microstructure of the UV-exposed itPP films were investigated using scanning electron microscopy, infrared spectroscopy, differential scanning calorimetry, and wide- and small-angle X-ray scattering. Photooxidative degradation was inhibited as the orientation degree of the itPP film increased. These results indicate that photooxidation likely occurs in the amorphous phase of itPP. Oriented molecular chains effectively slowed the photooxidative degradation of the itPP films. The artificial fragmentation test of UV-exposed itPP films showed that itPP films with lower crystallinity and orientation degrees were crushed into microplastics that were much smaller in size than those with higher crystallinity or orientation degrees.

Two types of lamellar stacking model were proposed for the inner structure of the melt-grown spherulites of isotacticpolypropylene (iPP): the edge-on structure (flat lamellar planes stand on the spherulite plane, and a*-axis // growth direction of spherulite, b-axis ┴ spherulite plane, and c-axis // spherulite plane) and the flat-on structure (flat lamellar planes lay on the spherulite plane, a*-axis // growth direction, b-axis // spherulite plane, and c-axis ┴ spherulite plane). After a literature review was performed, the observed X-ray scattering data were not high quality and could not be used to establish these bimodal structures; moreover, the X-ray data analyses were not performed satisfactorily. As a result, the derivations of actual structures were still debatable. We performed simultaneous time-resolved WAXD/SAXS measurements using a synchrotron X-ray microbeam technique. The collected data were classified into three sets of completely different WAXD/SAXS patterns. Detailed quantitative analysis enabled the determination of the spatial orientations of the stacked lamellae and related crystallographic axes. Although the bimodal structure of iPP spherulites was considered to be a well-known and already-established concept for long years, the bimodal structure was successfully confirmed for the first time in the present study, making the concrete discussions on the growth mechanism of the iPP spherulites possible.

The profound impact of the central metal on the morphological properties of metalloporphyrins bearing 3,4,5-tri((S)-dihydrocitronellyloxy)phenyl groups at the diagonal meso-positions is disclosed. Systematic comparison of the free-base porphyrin 1H2with metalloporphyrins 1Ms incorporating Ni(II), Cu(II), and Zn(II) as the central metal found the counterintuitive antifreezing effect of the central metal; 1H2crystallizes immediately after the removal of the solvent, while the central metal retards nucleation. We interpret that the miscibility of the elastic alkyl chains and the porphyrin segment is crucial in imparting fluidity to 1Mand smooth nucleation in the context of classical nucleation theory, while the full rationalization of the thermal behaviors requires the existence of the nuclei precursor according to the two-step nucleation model. The morphological behaviors of 1Ms are highly susceptible to only marginal differences in the chemical structure, presumably due to the relatively large discrete size of the porphyrin ring, approximately 1 nm. The somewhat counterintuitive antifreezing effect of the central metal is interpreted to arise from the increased viscosity due to the enhanced molecular interactions.

Spider’s minor ampullate silk, or MI-silk, exhibits distinct mechanical properties and water resistance compared to its major ampullate counterpart (MA-silk). The principal protein constituent of MI-silk is known as minor ampullate spidroin, or MiSp, and while its sequence has been deciphered and is thought to underlie the differences in properties with MA-silk, the composition of MI-silk and the relationship between its composition and properties remain elusive. In this study, we set out to investigate the mechanical properties, water resistance, and proteome of MA-silk and MI-silk from Araneus ventricosusand Trichonephila clavata. We also synthesized artificial fibers from major ampullate spidroin, MaSp1 and 2, and MiSp to compare their properties. Our proteomic analysis reveals that the MI-silk of both araneids is composed of MiSp, MaSp1, and spidroin constituting elements (SpiCEs). The absence of MaSp2 in the MI-silk proteome and the comparison of the water resistance of artificial fibers suggest that the presence of MaSp2 is the reason for the disparity in water resistance between MI-silk and MA-silk.

Covalently cross-linked rubber materials are widely used in elastic applications due to their excellent mechanical properties. However, the irreversibility of covalent cross-linking suffers from poor material recyclability. As a degradable polypeptide-based cross-linker for polybutadiene, poly(l-cysteine) (polyCys) was synthesized via papain-catalyzed chemoenzymatic polymerization. The resulting polyCys had intact thiol groups that cross-linked polybutadiene via the thiol-ene reaction. The cross-linking reaction of polybutadiene was performed in the presence of polyCys and a radical initiator and resulted in insoluble polybutadiene gel formation. Based on Raman spectroscopy analysis, the cross-linking reaction was confirmed by the consumption of thiol groups of polyCys. From the dynamic viscoelastic analyses of the cross-linked polybutadienes, the viscoelasticity drastically changed from that of raw polybutadiene, with the disappearance of the slow relaxation mode at low frequencies. The complete network formation was confirmed by E′ and E′′ showing the power law over the whole frequency range, as determined by the time-course experiments of the dynamic viscoelastic properties. The cross-linked polybutadiene was degradable by acid hydrolysis, resulting in the regeneration of soluble polybutadiene. Polypeptide cross-linked polybutadiene materials are promising candidates for the application of polybutadiene-based rubber materials with the requirements of both material integrity and reusability.

His-containing polypeptides, including polyHis, are attractive materials due to the unique characteristics of the imidazole ring of the His residue. In particular, His-containing polypeptides with repetitive sequences have a variety of distinctive features based on their periodic structure. In this study, chemoenzymatic polymerization of ethyl ester monomers with sequences His, GlyHis, HisGly, and GlyHisGly with hydrophobic side chains on the imidazole ring was performed using papain as a catalyst. Sequence dependence in chemoenzymatic polymerization was observed for GlyHis- and HisGly-based monomers: GlyHis-based monomers did not undergo polymerization, whereas polymerization of HisGly-based monomers afforded polypeptides with a degree of polymerization from 6 to 38 and from 5 to 31 and a number-average degree of polymerization of 16.4 and 12.4 for poly(HisGly) and poly[His(Bu)Gly], respectively. The difference in polymerizability of these dipeptide monomers was supported by a docking simulation between these monomers and papain, where the ester group of the HisGly-based monomer was closer to the catalytic center of papain than that of the GlyHis-based monomer. Infrared spectroscopy and synchrotron wide-angle X-ray diffraction measurements indicated that poly(HisGly) formed a β-sheet structure whose crystallinity was 41.6%, whereas the other tripeptide-based polypeptides were more amorphous showing 19.6–30.7% of crystallinity. Poly(HisGly) exhibited the highest thermal stability among all of the polypeptides in the thermogravimetric analysis, reflecting the difference in the secondary structures.

Isothermal crystallization kinetics from the melt of microbial poly(3-hydroxybutyrate) (P3HB) and poly(3-hydroxybutyrate-co-3-hydroxyhexanoate) (PHBH) were successfully investigated for ca. 50 nm thick ultrathin films on a molecular-to-lamellar scale by time-resolved grazing-incidence wide-angle X-ray diffraction (GIWAXD) and small-angle X-ray scattering (GISAXS) measurements using synchrotron radiation. The nucleation and crystallization rates were much lower in the ultrathin films than in the bulk at crystallization temperatures, Tcs, of 60, 70, and 80 °C. Moreover, it was suggested that the first-formed metastable crystal structures were more disordered in the ultrathin films than in the bulk. The molecular diffusion rate for crystallization was lower in the ultrathin film than in the bulk. The crystal growth rate might also be lower in the ultrathin film than in the bulk. The transformation from an edge-on-rich to a flat-on-rich lamellar orientation occurred only in the P3HB ultrathin films at higher Tcs. The lamellar stacking manner in the ultrathin films was more disordered for PHBHs having a higher 3HH content.

To clarify the details of the inner structure of polyethylene spherulites and the mechanism of the lamellar twisting phenomenon, we performed simultaneous step-scan measurements of wide-angle and small-angle X-ray scattering by using a synchrotron X-ray beam of μm size as well as atomistic simulation of the lamellar plate. Assorted new structural information has been extracted: (i) the chain axis is tilted by 15~22° from the normal to the lamellar plane, correcting the previously reported evaluation; (ii) the a- and b-axial lengths of the unit cell change periodically along the radical direction; and (iii) the lamellar twisting pitch is longer in the central part of the spherulite and adopts a constant shorter value in the equilibrated outer part. Second, in association with these experimental results, molecular mechanics calculations were performed to confirm the role of folded chain parts as a trigger of the lamellar twisting phenomenon. The calculated tilting angle of the chain stems was approximately 13°,and the calculated helical pitch for 180o-lamellar twisting was approximately 2 μm, which is in good agreement with the X-ray-observed values.

Poly(1,2-difluoroethylene) (PVLF, −[CHFCHF]n−), a member of representative fluorine polymers, was synthesized about half a century ago by the γ-ray-irradiated radical polymerization reaction as well as by the emulsion polymerization reaction (Durrell et al.). The thus-polymerized PVLF was reported to be atactic and amorphous according to the analysis of its 19F-NMR data and X-ray diffraction data (not given). In the present report, we have successfully synthesized PVLF by a different type of radical polymerization reaction in solution. The newly measured 19F-NMR spectral profile was essentially the same as that before. The solution-cast and melt-quenched samples were almost amorphous as known from the X-ray diffraction measurements. However, once the samples were heat-treated above the glass transition temperature (about 100 °C), sharp X-ray diffraction peaks were observed to appear. The differential scanning calorimetry (DSC) data exhibited a clear endothermic peak at around 200 °C, corresponding to the melting point. In addition, the thermal, mechanical, and physicochemical properties of this newly synthesized PVLF sample have been investigated by means of wide-angle X-ray diffraction, small-angle X-ray scattering, infrared absorption spectra, DSC, and viscoelastic data. All these experimental data revealed that PVLF is a semicrystalline polymer, not totally amorphous as had been reported before, and it exhibits various characteristic behaviors. PVLF had been forgotten because of its long-time misunderstanding as an amorphous polymer species. However, the present study has allowed PVLF to become a new member of crystalline fluorine polymers.

In this study, thin fiber composite polymer electrolyte membranes (PEMs) were prepared using short side-chain perfluorosulfonic acid (PFSA) ionomers, Aquivion, to create composite PEMs with improved proton conductivity and improved mechanical properties. PFSA thin fiber webs prepared by blow spinning and successive hot pressing were used as the porous substrate. Herein, PFSA ionomers were used for both the substrate and the matrix of the composite PEMs, and their structures, properties, and fuel cell performance were characterized. By adding the PFSA thin fiber webs to the matrix, the proton conductivity was enhanced and the mechanical properties were slightly improved. The prepared PFSA thin fiber composite PEM showed better FC performance than that of the pristine PFSA one for the high-temperature low-humidity condition in addition to the low-temperature high-humidity one. To the best of our knowledge, this is the first report on the all PFSA composite membranes containing a PFSA thin fiber framework.

Molecular aggregation structure and mechanical as well as thermal properties of novel well-defined multiblock copolymers consisting of crystalline syndiotactic polystyrene (sPS) and rubbery hydrogenated polyisoprene (hPIp) were investigated. The morphology and crystalline ordered structure of the multiblock copolymer films prepared by solvent casting from 1,2-dichlorobenzene solution depended on the volume fraction of sPS (VFsPS) and number of blocks. The multiblock copolymer films exhibited ordered morphology with low crystallinity. The crystallinity of the sPS reduced with decreasing the VFsPS. The pentablock copolymer produced more ordered morphology and less crystallinity than the triblock copolymers. The anisotropic orientation and mechanical stability of the δ form sPS crystals in the spherical sPS domains during uniaxial stretching were demonstrated. Tensile testing and dynamic mechanical analysis indicated that these multiblock copolymer films with appropriate sPS fraction are strong, tough, and elastic and thus could be potential candidates for a new type of thermoplastic elastomer with discrete crystalline hard domains.

Inspired by the natural spinning process, we developed an aqueous wet spinning system using a citrate buffer with polyethylene glycol (PEG), where the citrate buffer served for ion exchange and acidification and the PEG functioned for dehydration. This biomimetic condition induced the formation of solid fibers with a core–shell structure. The PEG layer could be subsequently removed by the equipped water bath, resulting in amorphous silk fibers. Due to the amorphous state, the silk fibers could be stretched at up to 12 times the original reel speed. Eventually, the mechanical properties featured an extraordinary extension of ~100% and a toughness of ~70?MJ/m3. The crystalline state of the resultant fibers was characterized by synchrotron WAXS to determine the degree of crystallinity and orientation of the beta-sheet structure. Interestingly, the citrate buffer-mediated spinning system enabled tuning of the induction of crystallization by changing the citrate buffer concentrations and coagulation time. The current amorphous spinning of regenerated silk fibers provided in-depth insights into the green and sustainable fabrication of artificial capture-silk-like fibers with unique extensibility and toughness.

Morphological control of C60fullerene using liquefied porphyrins (1and 2) as the host matrices was explored. Slow evaporation of the solvent of the equimolar mixture of porphyrin and C60in toluene afforded the porphyrin/C60composite with a 3:1 molar ratio. The stoichiometric binding behaviors suggest that specific porphyrin–C60interactions operate the formation of the porphyrin/C60composites, as corroborated by spectroscopic and thermal properties, and glazing-incidence wide-angle X-ray diffraction. Under the bulk conditions, the conventional thermodynamic advantage of multiple binding cooperativity for molecular recognition is unlikely to explain the stoichiometric binding behaviors. Instead, we propose a size-matching effect on the porphyrin–C60interaction in the bulk porphyrin matrices, i.e., “supramolecular solvation”. The glassy nature of the porphyrin matrices was transmitted to C60through the specific interaction, and the porphyrin/C60composites adopted glassy states at room temperature.

A polypeptide with a GlyHisGly repeating sequence containing zwitterionic structures that effectively interact with cellulose was synthesized for dissociation of cellulose crystals. Polypeptide with the GlyHisGly sequence was synthesized by chemoenzymatic polymerization and postfunctionalization of the His residues was performed to afford imidazolium butyrate on the side chains. The resulting zwitterionic polypeptide effectively dissociated bundles of tunicate cellulose nanocrystals, even when the conditions were mild and the concentration of the polypeptide was as low as 1–2 mg mL–1. Polypeptide treatment also affected the morphology of the cell walls in cultured plant cells, and the cellulose microfibril networks and amorphous polysaccharide layer were dissociated according to atomic force microscopy (AFM). The zwitterionic polypeptide treatment did not change the crystal structure of the cellulose nanocrystals. Analysis of the mechanical properties of the cellulose nanocrystals by force curve measurements using AFM revealed that the elastic modulus of the cellulose nanocrystals increased after treatment with the zwitterionic polypeptide, indicating that the amorphous part of the cellulose nanocrystals was removed by interactions with the polypeptide. At a concentration of the polypeptide that enabled the dissociation of the cellulose network, the zwitterionic polypeptide showed negligible cytotoxicity to the plant cells. The mild and noncytotoxic technique for loosening cellulose microfibrils/nanocrystals that was developed in this study has tremendous significance for the modification of cellulose in terms of polymer chemistry, material science, and plant biotechnology.

In order to investigate the effects of bulky substituents on the crystal structures and packing modes, N-benzyl (Bn) and N-2-phenylethyl (EtPh) substituents are introduced in bisthienoisatin (BTI), thienoisoindigo (TIIG), and dibenzothienoisoindigo (DBTII). These molecules maintain uniform stacking structures, though EtPh-BTIhas a two-dimensional slipped-herringbone structure. The benzyl groups are largely distorted from the molecular core, and thin films of Bn-TIIGand Bn-DBTIIshow poor quality due to the two kinds of molecular orientations. In contrast, the 2-phenylethyl-substituted molecules enable suitable molecular packing owing to the ethylene spacer and show relatively good thin-film qualities as well as much improved transistor properties. The BTIderivatives show only electron transport, but other compounds exhibit ambipolar transistor properties. In particular, EtPh-TIIGand EtPh-DBTIIshow maximum hole mobilities of about 0.04–0.05 cm2V–1s–1together with moderate electron mobilities.

Polypeptides containing periodic aromatic residues in their main chains were synthesized via papain-catalyzed chemoenzymatic polymerization of tripeptide ester monomers under moderate conditions in aqueous buffers. As the monomer, 4-aminobenzoic acid (Abz) was modified with Gly or Ala at the N- and C-termini to mitigate the poor substrate specificity of papain to unnatural amino acids. The tripeptide esters, namely, GlyAbzGly and AlaAbzAla ethyl esters, can be recognized and polymerized by papain, resulting in the polypeptides poly(GlyAbzGly) and poly(AlaAbzAla), respectively, with periodic sequences containing Abz units every three residues. Copolymerization of tripeptide esters with Gly or Ala ethyl ester also proceeded in the presence of papain. The secondary structures of the Abz-containing polypeptides were investigated by IR and wide-angle X-ray diffraction (WAXD) analysis. The WAXD profile of poly(GlyAbzGly) was similar to that of polyGly, whereas poly(AlaAbzAla) adopted a sheet-like structure similar to the β-sheet of polyAla. Thermal analysis of Abz-containing polypeptides revealed that the high thermal stability of the Abz-containing polypeptides is related to the distinct sequences that periodically include Abz residues.

“Secondary doping” in poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS) is quite effective and a frequently used method for the conductivity enhancement. This simple approach, the addition of co-solvents to the PEDOT:PSS solution before film fabrication, is an essential way to derive the high electrical performance of PEDOT:PSS, but the mechanism still remains unclear. In this study, nanoscale structural changes synchronized with the conductivity enhancement via secondary doping in PEDOT:PSS films were investigated. During secondary doping with ethylene glycol near the critical dopant concentration, noncrystalized PEDOT molecules uncoupled from PSS chains and then underwent nanocrystallization. These structural changes might be the key driving force for conductivity enhancement via secondary doping.

The role of strain rate (ε̇) in the strain-induced crystallization (SIC) of vulcanized natural rubber (NR) and synthetic isoprene rubber (IR) was studied using in situ wide-angle X-ray scattering (WAXS) (synchrotron X-ray radiation). We developed homemade extension equipment and coupled it with the synchronized time-resolved X-ray detector system. The nucleation rate (I) was determined for a wide range of ε̇values (0.0075 s−1–330 s−1) based on the increase in the scattering intensity (IX) as a function of time (t). We found that Iis proportional to ε̇(I∝ε̇). Based on this result, we concluded that ε̇plays an important role in the kinetic mechanism of the SIC of NR and IR.

Fibril-sized structures, which exhibit a density fluctuation of several tens to hundreds of nanometers, are important because they influence many properties of fibers and films, particularly the strength and thermal shrinkage of synthetic fibers. We analyzed the formation of fibril-sized structures after necking using ultra-small-angle X-ray scattering (USAXS), which enables observation of the void and craze formations. Continuous laser-heated drawing and undulator synchrotron radiation were adopted to measure the structural development of poly(ethylene terephthalate) (PET) and poly(phenylene sulfide) (PPS) fibers. Both fibers showed a clear increase in the meridional streak intensity just after necking and an increase in the equatorial streak after necking. These increases were distinctive for PPS. Moreover, a layer-lined streak appeared after necking only for PET. The intensity of the meridional streak increased with an increase in the draw ratio, whereas the intensity of the layer-lined scattering decreased with an increase in the draw ratio.

Graphdiyne (GDY) comprises an important class in functional covalent organic nanosheets based on carbon–carbon bond formation, and recent focus has collected in the expansion of its variations. Here we report on the synthesis of a GDY analogue, TP-GDY, which has triphenylene as the aromatic core. Our liquid/liquid interfacial synthesis for GDY (J. Am. Chem. Soc.2017, 139, 3145) was modified for hexaethynyltriphenylene monomer to afford a TP-GDYfilm with a free-standing morphology, a smooth texture, a domain size of >1 mm, and a thickness of 220 nm. Resultant TP-GDYis characterized by series of microscopies, spectroscopies, and thermogravimetric and gas adsorption analyses.

The performance of polymer electrolyte fuel cells (PEFCs) depends on the structure of catalyst layer which is formed by coating catalyst ink. This study investigated the nanostructural formation of catalyst layer during ink drying process using time-resolved grazing-incidence small-angle X-ray scattering (GISAXS). GISAXS patterns measured for the catalyst ink coated with a 100 um thickness on a silicon wafer suggest that Pt/C aggregation completed at drying time (t) of 250 sec although the ink was completely dried at t = 1600 sec. Thus, the Pt/C aggregate structure was mostly pinned in the early stage of the drying.

We studied the elongational crystallization of poly(ethylene terephthalate) (PET) from the melt using polarizing optical microscope and X-ray observation. We verified that the structure and morphology discontinuously changed from conventional stacked lamellae of folded chain crystals (FCCs) to nano-oriented crystals (NOCs) when the elongational strain rate ($$\dot \varepsilon $$ ε° ) exceeded a critical value of $$(\dot \varepsilon ^*) \cong 10^2\,{\mathrm{s}}^{ - 1}$$ (ε°*)≅102s-1 . Therefore, the universality of NOC formation was verified. We found that the NOCs of PET show a novel three-dimensional (3D) structure and morphology: (i) nanocrystals (NCs) were arranged in a monoclinic lattice, which is a specific morphology for NOCs of PET, compared to iPP, and (ii) the unit cell structure of NOCs was a triclinic system with biaxial orientation. We showed the important role of the primary structure of the plate, such as a benzene ring, in the formation of a novel 3D structure and the morphology of the NOCs of PET. We also clarified that the NOCs of PET showed high performance, such as a high heat resistance temperature (Th)$$\ \cong\ $$ ≅ 281 °C, a high melting temperature (Tm)$$\ \cong\ $$ ≅ 285 °C, high maximum tensile stresses for the machine direction (MD) and transverse direction (TD)$$\ \cong\ $$ ≅ 2.8 × 102and 74 MPa, respectively, and high Young’s moduli for MD and TD $$\ \cong\ $$ ≅ 5.4 and 1.7 GPa, respectively. We studied the elongational crystallization of poly(ethylene terephthalate) (PET) from the supercooled melt. We found that the novel three-dimensional (3D) structure of “nano-oriented crystals (NOCs)” was formed, where nanocrystals (NCs) were arranged on monoclinic lattice. We observed the structure and morphology of NOCs by means of polarizing optical microscope and small/wide angle X-ray scatterings. We clarified the important role of a primary structure of the plate-like benzene ring in the formation of the NOCs of PET. We also showed high performance of NOCs of PET, such as high heat resistance temperature and high maximum tensile stress.

Bis(diimino)nickel (NiDI) nanosheet is prepared by two methods of oxidation-promoted interfacial coordination reactions of nickel(II) ions with hexaaminobenzene. The thickness of the large chemically formed NiDI nanosheet can be controlled from atomic layers to thousands of layers. The morphology of electrochemically formed NiDI-modified electrode achievable within a minute suggests longitudinal growth of nanosheets at the surface. Increasing capacity of the NiDI with its amount indicates NiDI as a promising energy storage material.Bis(diimino)nickel (NiDI) nanosheet is prepared by two methods of oxidation-promoted interfacial coordination reactions of nickel(II) ions with hexaaminobenzene. The thickness of the large chemically formed NiDI nanosheet can be controlled from atomic layers to thousands of layers. The morphology of electrochemically formed NiDI-modified electrode achievable within a minute suggests longitudinal growth of nanosheets at the surface.

The film formation process of blade-coated catalyst ink was investigated by in-situ time-resolved grazing-incidence small-angle X-ray scattering (GISAXS) measurements utilizing synchrotron radiation. The GISAXS profiles were measured as a function of the time elapsed after coating the ink, t. As increasing t, the peak at around qz ~ 0.2 nm[?]1 shifted toward smaller qz. At t ~ 50 s, two peaks appeared at around qz ~ 0.5 nm[?]1 and then combined into one peak. These peak shifts would be ascribed to Pt/C agglomeration induced by solvent evaporation.

Owing to its exceptional chemical stability and proton conductivity, perfluorosulfonated ionomer (Nafion) is widely used as a polymer electrolyte in many electrochemical devices, such as chlor-alkali cells, fuel cells, and water electrolyzers. Herein, magnesiated perfluorosulfonated ionomer (Nafion-Mg)-based gel electrolytes swollen in magnesium bis(trifluoromethanesulfonyl)amide/triglyme (Mg(TFSA)2/G3) solutions were prepared, and their structures and electrochemical properties were investigated. Mg(TFSA)2/G3 solutions facilitate the expansion, connection, and integration of the ionic domains of the Nafion, subsequently causing drastic swelling. The prepared Nafion gel electrolytes swollen in a 0.5 M Mg(TFSA)2/G3 solution showed good ionic conductivity of 1.05 × 10–3S cm–1and a Mg-ion transference number of 0.40 at 80 °C. They also displayed reversible Mg deposition/dissolution behavior and an electrochemical window of +3.8 V vs Mg2+/Mg. To the best of our knowledge, this is the first study on the structural and electrochemical characterization of magnesium ion-exchanged Nafion swollen in a Mg(TFSA)2/glyme solution.

In this study, we investigated the effect of morphology on the gas-transport properties of a poly(ether-block-amide) (PEBA) multiblock copolymer. We annealed the copolymer samples and varied the annealing temperature to evaluate the influence of changes in the microstructure on the gas transport properties of PEBA. In addition, we used time-resolved attenuated total reflection Fourier transform infrared spectroscopy to evaluate the diffusion coefficient of CO2in PEBA based on the Fickian model. The effect of the annealing temperature on the microphase-separated structure of the multiblock copolymer is discussed in detail. Furthermore, the gas diffusivity was significantly affected by the purity of the soft domains. The annealed sample demonstrated a 38% increase in CO2permeability while maintaining a high CO2/N2permselectivity of approximately 53. The findings of this study provide valuable insight into the design and optimization of PEBA membranes for gas separation applications.

The dynamics of thin-film formation process from Nafion solution induced by solvent evaporation were investigated by in-situ time-resolved grazing-incidence small- and wide-angle X-ray scattering (GISAXS/GIWAXS) measurements utilizing synchrotron radiation. GISAXS/GIWAXS measurements revealed subnano- to nano-scaled structural development during thin-film formation process from Nafion solution. In the early stage, solvent evaporation decreased the distance between the scatter structures in Nafion solution. With the solvent evaporation, the ordered structures with a spacing of 3.3 nm appeared and finally solidified. In-situ time-resolved GISAXS/GIWAXS techniques provide a powerful tool to investigate the development of structures during thin-film formation process from polymer solutions including ionomer solution.