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While the physical properties of polymer solution have been extensively investigated, less is explored at the vicinity of vitrification due to the experimental difficulty. In this study, we analyzed polymerization-induced vitrification during bulk polymerization of methyl methacrylate. Dielectric spectroscopy captured vitrification caused by the change of polymer concentration at a constant temperature. Our study shows that the polymerization solution becomes heterogeneous at the vicinity of vitrification. In addition, this heterogenization coincides with the reaction acceleration classically known as the Trommsdorff effect.
In this review, the advantages associated with the molecular design of peptides as multifunctional templates for mineralization are initially described. Subsequently, the mechanisms of CaCO3 nucleation and selective crystal growth achieved under biomimetic mineralization conditions using the designed peptide templates are discussed. Finally, the functional design of peptide–inorganic hybrid materials based on structural control and the use of a mineralization method that can be applied in the engineering and medical fields is considered from the viewpoint of the molecular properties of the peptides.
Two specific concepts have emerged in the field of materials science over the last several decades: nanosheets and supramolecular polymers. Based on this background, supramolecular nanosheets, in which these two concepts are integrated, have recently attracted particular attention. This review focuses on design of two supramolecular nanosheets. One is tubulin protein-based supramolecular nanosheet for applications to GTP-responsive drug delivery system. The other is phospholipid-based supramolecular nanosheets and their applications in blood-administrated drug delivery systems.
In our study, a continuous change of tensile strength (26.9–49.5 MPa) and impact strength (4.7–23.2 KJ/m2) of iPP samples is successfully accomplished without the specific catalysts. The high content of γ-crystal with thin lamellar thickness related to the ductility property is also experimentally confirmed. A morphology of the diagram is proposed based on the composition and molded technology.
Bis(3-aminopropyl)-DDSQ was employed for polymerization with various aromatic dialdehydes to obtain poly(azomethine)s with high double-decker-shaped phenylsubstituted silsesquioxane (DDSQ) contents in the main chain. Introducing the flexible propylene linkers in the DDSQ unit provided flexible and optically transparent free-standing films. Their mechanical properties were highly dependent with the structures of the dialdehyde co-monomers.
Cashew nut shell liquid (CNSL) is a natural phenolic compounds that is non-edible biomass. A novel diglycidyl ether (BCNDGE) derived from CNSL was synthesized and used as a building block to formulate an epoxy resin. Epoxy resins were cured from BCNDGE and commercial diglycidyl ether (BPADGE) with acid anhydride hardener. BCNDGE content improved the thermal stability and flexibility of the epoxy compared with commercial BPADGE-based epoxy. Hence, BCNDGE is a promising novel diglycidyl ether candidate with high biomass content to act as an alternative to petroleum-based chemicals for epoxy resins.
The coil-to-globule-to-coil transitions of a zwitterionic polymer, poly(2-[(N-2-methacryloyloxyethyl-N,N-dimethyl)ammonio]acetate) (PCB2), in water, ethanol, and water–ethanol mixed solvents were investigated and compared with those of poly[2-(methacryloyloxy)ethyl phosphorylcholine] (PMPC). PCB2 showed cononsolvency in water–ethanol mixed solvents with specific ethanol volume fractions. PCB2 showed a broader cononsolvency range than PMPC because of its lower association constants of water and ethanol and the marked competition for hydrogen bonding. The zwitterion-specific cononsolvency characteristics were rationalized with the electrostatic potentials and van der Waals energies of the zwitterions.
Supramolecular chiral emergence from achiral molecules is studied using newly designed amphiphilic polypeptides upon self-assembling into nanosheets and vesicles in water. The polypeptide, SL-π-D, contains a hydrophilic poly(Sar) block, two hydrophobic helical blocks, and a π-conjugate block. The helical blocks possess right- and left-handed helices, compensating for helical chirality resulting in an achiral molecule. SL-π-D self-assembled in trifluoroethanol/water solutions into uniform nanosheets and vesicles, with the Cotton effect appearing in the achiral π-conjugate block. Supramolecular chiral emergence intrinsically arises from the molecular structure and is enhanced in vesicular morphology.
Here, we introduce a candidate material, water-soluble guanidinylated chitosan (WGCS), for a protein delivery system. WGCS composed of 48.2% guanidinylated chitosan, 20.6% chitosan, and 31.2% chitin units was prepared from low-molecular-weight chitosan (CS). WGCS showed ca. 2.5-fold higher internalization into HeLa cells than CS does. Moreover, we found that WGCS significantly enhanced the internalization of bovine serum albumin in transport medium at pH 7.4.
Quantifying the interfacial energy of a polymer–liquid interface is challenging. We previously succeeded in analyzing the interfacial energy of a dynamic polymer brush interface by measuring the deformation of an ultrathin elastomer film floating on water. However, the quantitativity remains debatable because the bulk modulus was used. In this study, we reanalyze the interfacial energy using the ultrathin-film modulus. Large negative interfacial energy was observed for the system of high-density stretched brushes. The free energy balance for the system floating on water was calculated, validating the negative interfacial energy.
