Thank you for visiting nature.com. You are using a browser version with limited support for CSS. To obtain
the best experience, we recommend you use a more up to date browser (or turn off compatibility mode in
Internet Explorer). In the meantime, to ensure continued support, we are displaying the site without styles
and JavaScript.
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.
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.
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.
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.
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.
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.
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.
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.
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.
10,12,14,16,18,20-Triacontahexayne-1,30-diol and its diphenylurethane and diphenylester were synthesized, and their solid-state polymerization behaviors were investigated. The regular two-step solid-state polymerization was confirmed for the diphenylurethane derivative.
When methanol, a non-solvent, was added to dilute THF solutions of an optically active polyfluorene derivative, the liquid–liquid phase separation took place, and circular dichroism (CD) was induced at a low temperature. The CD induction upon cooling was a rather slow process, according to the first-order reaction kinetics. The intermolecular chiral interaction in the concentrated phase may be responsible for the CD induction or nonracemization of this helical polyfluorene derivative in phase-separating solutions.
Sulfur-containing acrylic monomers were developed for high refractive index. The index of polymer films increased with the number of sulfur atoms in the monomer structure. Trisulfur-acrylic polymer provided refractive indices of more than 1.72 at visible light. Dipolar phenyl structure significantly increased the refractive index of acrylic polymers. Wavelength dispersion of the refractive index was investigated with Abbe's number of ca. 30 for all polymer films, except for the dipolar polymer viewing Abbe's number of ∼41.