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As a new conformational motif of vinyl polymers having side-chain π-electronic groups, we have introduced a ‘π-stacked structure’ in which side-chain chromophores are regularly stacked on top of each other and main-chain C-C bonds have a nearly all-trans, zigzag conformation. π-Stacked polymers can be prepared by vinyl polymerization of dibenzofulvene (DBF) and its derivatives. On the basis of the controlled structure, poly(DBF) and its derivatives exhibit unique photophysical and electronic properties as vinyl polymers. Introduction of chirality to π-stacked polymers was also achieved.
The thermal relaxation of a monolayer of PMMA deposited on a thick film was discussed by the direct observation of single chains using scanning near-field optical microscopy (SNOM). The polymer chain of the monolayer penetrated into the bulk substrate with a diffusion rate much faster than that of the translational diffusion of the entire chain. Conversely, the radius of gyration in the lateral direction was maintained throughout the relaxation process.
Interaction between a chiral polymer obtained by cyclopolymerization of a bisacrylamide [poly(1)] and aromatic aldehydes was investigated by CD, NMR and IR measurements. The observed induced CD demonstrated that the chiral frameworks of poly(1) forced aldehydes to remain in a chiral environment. NMR and IR measurements on the mixtures of poly(1) and aromatic aldehydes suggested that carbonyl groups interacted with the polymer.
Multihybrid particles having a gold core, silica as an inital shell and polymethylmethacrylate (pMMA) as a second shell (Au@SiO2@pMMA) were synthesized and assembled in two to three dimensions using the Langmuir–Blodgett technique.
The prospect of this study was to eliminate inter- and intramolecular crosslinks and to synthesize water-soluble phoshorylated chitosan through the phosphorus pentoxide/methanesulphonic acid system. The influences of ethanol washing and sodium salt formation on the elimination of inter- and intramolecular crosslinks were investigated. It was found that the obtained sodium phosphorylated chitosan was water soluble independent of the degree of phosphoric substitution.
The static partial scattering functions for linear and ring random copolymers of type A–B are investigated. In the case of random distribution of monomers, analytic forms can be derived. Monte Carlo simulations are used to make evaluations on biased distributions of monomers. Results show that the number, fraction and distribution of monomers have a significant effect on intensities at sufficiently large scattering angles. The scattering function in molten state is also calculated by random phase approximation.
Calcium alginate gels containing hydroxyapatite were prepared in one step and evaluated with regard to pH dependence and electrochemical property for applying to drug carriers. The composite gels immersed in a pH indicator solution changed its color by applying voltage. By these results, it was revealed that pH alteration of composite gels occurred by electro-osmosis and electrophoresis. Swelling and shrinking of the composite gels were controlled by external stimuli of pH and voltage and the content of hydroxyapatite.
Fluoroalkyl end-capped N-(1,1-dimethyl-3-oxobutyl)acrylamide oligomer [RF-(DOBAA)n-RF] in silica nanocomposite can exhibit a nonflammability characteristic even after calcination at 800 °C, through the formation of ammonium hexafluor osilicate corresponding to −154.8 p.p.m. signal in 19 F MAS NMR spectra during the nanocomposite reactions; in contrast, no formation of ammonium hexafluorosilicate during the composite reaction affords a usually flammable behavior for RF-(DOBAA)n-RF oligomer in silica nanocomposite.
Glycopolymer-substituted gold substrates were prepared by means of living radical polymerization with a reversible addition-fragment chain transfer (RAFT) reagent. Thiol-terminated glycopolymers were bound to the gold substrate to yield the polymer-substituted interface. In the case of the gold substrate, the interactions with proteins (lectins and Shiga toxins) were analyzed by surface plasmon resonance (SPR). The interactions were highly specific and the signal-to-noise ratio of protein recognition was more than 16.
Transparent organic–inorganic nanocomposites were successfully synthesized from poly(arylene ether ketone)-based matrix polymer and BaTiO3 nanoparticles. The dispersibility of nanoparticles was significantly improved by both the introduction of phosphonic acid moiety into the polymer chain and the organic modification of the nanoparticle surface. Refractive index of the obtained transparent nanocomposite, which contains 44 wt% of BaTiO3, increased to 1.72 @ 589 nm.
We successfully prepared a new class of a reactive novolac (3) having a methylol moiety as a functional group derived from its precursor synthesized by the acid-catalyzed addition–condensation of a bisphenol A derivative and formaldehyde. Curing reaction between 3 and the low-molecular-weight phenolic resin (4) afforded the curing product, which showed enhanced thermal stability compared with 4 or the conventional phenolic resin. Consequently, 3 can be applied as a curing agent to modify the thermal property of 4.
A methacrylate monomer, having an N-(2-methoxyethyl)methylamino group and urea bond, was newly prepared. The methacrylate monomer was used for graft polymerization from polysilsesquioxane containing the dimethyl dithiocarbamate group as the initiator specie to provide thermoresponsive property. The grafted product showed hydrophobic aggregation at 30 °C in an aqueous solution. Copolymerization with 2-hydroxyethyl methacrylate was also examined to introduce the additional functional group.
