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Simple control of the thermoresponsive properties of polymers in water over a broad range is achieved by using a designed urethane-containing acrylamide monomer in combination with a hydroxy-containing precursor monomer, which forms a statistical sequence due to its similar backbone. The copolymers exhibited a lower critical solution temperature-type responsive behavior in water, and the effects of structural factors such as composition, molecular weight, end groups and side-chain structure in urethane monomers were systematically evaluated.
Schematic illustrations of the alignment behavior induced by SWaP. Photopolymerization was conducted with a scanned UV slit light. Uniaxial molecular alignment was induced when the polymer concentration in the exposure area was high, while it was random when the polymer concentration was low.
Natural rubber exhibits the strain-induced crystallization (SIC). By using WAXD, the orientation of NR crystal formed by SIC under planar elongation was revisited. We found that the orientational state of the crystal lattice possesses a continuous margin of the orientation angle between 6.4 and 19.6° for the ac plane with respect to the surface of the specimen sheet in the real NR specimen. This orientational state could be accomplished as a result of balancing the preferential parallel orientation of (120) planes (the slip planes) and C = C planes with respect to the surface of the specimen sheet.
We synthesized a new benzobisthiazole (BBTz) containing building unit in which two alkoxythiophenes were attached to the BBTz moiety so as to induce oxygen–sulfur noncovalent intramolecular interactions and thereby interlock the linkage. As a result, the π-conjugated polymer incorporating the new building unit, PDBTz2, had a more coplanar and rigid backbone than the alkyl counterpart, PDBTz1. Interestingly, the backbone orientation was completely altered from the edge-on orientation (PDBTz1) to the face-on orientation (PDBTz2), which is preferable for organic photovoltaics. Accordingly, PDBTz2 showed a much higher photovoltaic performance than PDBTz1.
The surface properties of the star polymer coating were evaluated with their resistance to protein adsorption and surface zeta (ζ)-potential to clarify the mechanism for inhibition of cell adhesion. The surface of the star polymer coating with a high density of poly(2-hydroxyethyl methacrylate) formed an electrically neutral diffuse brush structure in water and showed high resistance to protein adsorption. Considering the data obtained in the study, the surface ζ-potential and antibiofouling properties were correlated by controlling the molecular architecture of the coating material.
Developing fluorescence anion sensors is important because anions play a significant role in various biological phenomena. Herein, we evaluated the anion binding properties of a polyhedral oligomeric silsesquioxane (POSS) derivative with eight urea groups and a 3D structure. The results revealed that the POSS derivative with urea groups can bind to sulfate ions and exhibits a greater binding ability than that of the model compound because multiple urea groups exhibit cooperative effects. Through the introduction of naphthyl urea groups, the POSS derivative can be used as a fluorescence sensor for quantifying sulfate ions.
Soft interfaces formed by polymer materials are important interfaces for biological systems (biointerfaces). Controlled radical polymerization (CRP) is highly suited for designing biointerfaces composed of polymer chains because it enables precise control of the polymer architecture at the nanoscale. This focus review describes the design of functional soft interfaces based on investigations of the structure-property relationships of CRPs. In particular, polymer brush surfaces showing autonomous property changes, comb-type copolymer-driven 2D/3D transformations of lipid bilayers, and molecular interactions in bactericidal cationic polymer brushes are depicted.
Surface amino groups (SAGs) on nanochitin materials were quantified using three amino-labeling reagents and two cationic dyes. After binding to SAGs, the excess labeling reagents or generated molecules were assessed by spectrophotometry. The dyes were adsorbed onto SAGs, and the excess was similarly quantified. The obtained values were compared with the titration values. Although the values by labeling reagents were underestimated, some of the values were proportional to those by titration. Reliable results were attained using the two labeling reagents with conversion equations or using Acid Orange 7 adsorption.
The morphology and physical properties of polyisoprene ionomers co-neutralized with Na+ and Mg2+ in different ratios have been studied. The mechanical and self-healing properties of the ionomer were reinforced and disturbed, respectively, at over 25 % of the Mg2+ ratio, where linkage via Mg2+ in the network is pervasive throughout the material.
The in situ wide-angle (WAXD) and small-angle X-ray scattering (SAXS) measurements have been performed using a synchrotron microbeam technique for the melt-isothermally-growing iPP spherulites. The thus-collected data were found to be classified into three sets of totally different WAXD/SAXS patterns, from which the three different orientation modes of the stacked lamellae and related crystallographic axes were deduced. These structural information allowed us to discuss the growth mechanism of stacked lamellae in the iPP spherulites from the microscopic point of view.
Water-insoluble micropatterned films were prepared from poly(vinyl alcohol) (PVA) (or ethylene-vinyl alcohol copolymer (EVOH)) and poly(methacrylic acid) (poly(MAAc)). The carboxy groups in poly(MAAc) underwent dehydration reactions with the hydroxy groups in the vinyl alcohol units during heating at 135 °C, which resulted in the introduction of a crosslinked structure with ester bonds into the polymeric network of the micropatterned films. The micropatterns could be peeled off from the films after decomposition and maintained their patterned shapes.
Side-chain typed POSS-based polynorbornenes connecting with a short spacer exhibiting optical transparency owing to prevention of POSS crystallization to provide amorphous character. In addition, the resulting amorphous polymers exhibited excellent thermal stability.
A novel block copolymer, poly(3-hexylthiophene)-b-poly(vinyl catechol) (P3HT-b-PVC) was successfully synthesized via a Click reaction between chain-endfunctionalized P3HT with an alkyne group (P3HT-Alkyne) and chain-end-functionalized poly(3,4-di-tert-butyldimethylsilyloxystyrene) with an azide group (PSVC-Azide), followed by deprotection of tert-butyldimethylsilyloxy groups from the PSVC-Azide segment. Tape test results showed that the adhesion property of the P3HT-b-PVC film was considerably better than that of the corresponding P3HT film. Furthermore, despite the presence of an insulating PVC block in P3HT-b-PVC, the P3HT-b-PVC thin film exhibited a hole mobility comparable to that of the corresponding P3HT thin film.
This study explores the effects of long-term degradation on the viscoelastic properties of viscoelastic liquids using tetra-armed polyethylene glycol (Tetra-PEG) slimes as model material. It aims to enhance control over the viscoelasticity of biomedical materials, like sodium hyaluronate, by introducing specific cleavage sites into the Tetra-PEG slimes to simulate degradation. The study reveals that despite degradation, the slimes maintain a single relaxation mode, offering a method to design viscoelastic liquids with predictable and controllable degradation for biomedical applications.
A new peptide carrier that mimics the basic leucine zipper domain (bZIP) of DNA-binding proteins was designed, in which (LU)4 is the leucine zipper motif and (KUA)3 is the basic DNA-binding motif (U = α-aminoisobutyric acid). When mixed with pDNA, (KUA)3-(LU)4 peptide condensed DNA molecules to form nanoparticles. Furthermore, when complexes of the (KUA)3-(LU)4 peptide and pDNA were introduced into the leaves of Arabidopsis thaliana (A. thaliana), the reporter protein was expressed in plant cells. Thus, (KUA)3-(LU)4 is an efficient carrier of pDNA with high dissociation efficiency.
We report the humidity-responsive volume changes of a poly(N-isopropylacrylamide) (PNIPAAm) gel and bending deformation of a PNIPAAm and poly(N,N-dimethylacrylamide) (PDMAAm) complex gel.
In this study, the effects of the polyrotaxane cross-linker concentration and solvent content on elastomer preparation were investigated to obtain elastomers with high toughnesses due to the properties of the polyrotaxane cross-linking agent. If elastomers were prepared in a state in which the slide-ring effect of the polyrotaxane was easily expressed by the concentration of the polyrotaxane cross-linker and the amount of solvent, the elastomers obtained elongated more and were tougher than elastomers made from conventional cross-linkers.
Postpolymerization modifications of poly(2-methoxyethoxycarbonylmethylene) and poly(2-phenoxyethoxycarbonylmethylene) with mixtures of Me3SiCl and LDA efficiently transformed the alkoxycarbonylmethylene repeating units to ketene silyl acetals to yield a product with up to 93 mol% composition of the latter unit. TBAF-mediated benzylation of the highly silylated polymer with benzyl bromide yielded a polymer containing side chain O (major)- and main chain C (minor)-benzylated units along with the unreacted ketene silyl acetal unit.