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Boronic acid-based sensors for saccharides have been developed via biocatalysis. The self-doped copolymer of poly(aniline-co-3-aminobenzeneboronic acid) [poly(aniline-co-AB)], with various mole ratios of two components, was synthesized by oxidative enzymatic polymerization using a natural biocatalyst such as horseradish peroxidase together with an anionic polyelectrolyte template (sulfonated polystyrene) under mild conditions (pH 4.5). Poly(aniline-co-AB), having an aniline boronic acid-to-aniline ratio of 1:2 on average, gave rise to a green doped polymer with absorption maxima at 745 nm. The potentiometric detection of saccharides using poly(aniline-co-AB) is presented. Characteristics of both transient and steady-state response associated with the complex formation of poly(aniline-co-AB) with various saccharides were monitored by UV-vis spectroscopy and cyclic voltammetry (CV). The results obtained from UV-vis spectroscopy and CV show that the sensitivity of enzymatically synthesized water-soluble poly(aniline-co-AB) for various saccharides was improved significantly compared to the chemically synthesized counterpart. A possible mechanism for the sensitive detection of sugar molecules by boronic acid is proposed on the basis of UV-vis and IR spectrophotometry, and four-point probe conductivity measurements.

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ABSTRACT:A new type of polyimide/silica (PI/SiO 2 ) hybrid composite films was prepared by blending polymermodified colloidal silica with the semiflexible polyimide. Polyimide was solution-imidized at higher temperature than the glass transition temperature (T g ) using 3,3Ј,4,4Ј-biphenyltetracarboxylic dianhydride (BPDA) and 4,4Ј-diaminodiphenyl ether (ODA). The morphological observation on the prepared hybrid films by scanning electron microscopy (SEM) pointed to the existence of miscible organicinorganic phase, which resulted in improved mechanical properties compared with pure PI. The incorporation of the silica structures in the PI matrix also increased both T g and thermal stability of the resulting films.

Segmented poly(etherurethaneureas) (SPUUs) with hydrophilic and hydrophobic polyether components were prepared. The surface chemical composition of SPUUs in various environments was investigated by means of X-ray photoelectron spectroscopic and dynamic contact angle measurements. These measurements revealed that in a hydrated state, the higher surface free energy component is enriched on the surface of the SPUU in order to minimize the interfacial free energy between water and the solid surface. The surface molecular mobility showed a strong correlation with bulk molecular motion. Platelet adhesion tests and dynamic contact angle measurements after adsorption of bovine serum albumin revealed that the surface of SPUUs with hydrophilic soft segments has a non-adhesive nature. The platelet reactivity of hydrophobic SPUUs is influenced by microphase separation at the surface.

In this study, novel biodegradable polymers were synthesized by ring opening polymerization (ROP) of L‐lactide on chitin in an N,N‐dimethyl acetamide (DMAc)/lithium chloride (LiCl) solvent system, and chitin was used as macroinitiator to afford new materials. Lithium chloride (LiCl) was used as catalyst. The synthesized copolymers [chitin‐graft‐poly(L‐lactide) (PLLA)] were characterized by Fourier transform infrared (FTIR) spectroscopy to confirm the newly formed ester bond. From the FTIR spectra, the peak intensity of ester bond in the chitin‐graft‐PLLA copolymers increased in comparison to that of L‐lactide monomer. Therefore, it was confirmed that PLLA was successfully grafted on to chitin. Also, cross polarization–magic angle spinning (CP‐MAS), 13C solid state NMR spectroscopy and differential scanning calorimetry were used to characterize novel chitin‐graft‐PLLA copolymers.© 2002 Society of Chemical Industry

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