Ultrasound (US) exposure strongly influenced thermosensitivity of microgels attracted with both N-isopropylacrylamide (NIPAM) and acrylic acid (AA) segments, due to that hydrogen bonds of carboxylic acid segments in microgels were broken by US and then the hydration with water occurred. US induced critical effects on the volume phase transition temperature of the swelled NIPAM gel (PNAM). It was observed after the US exposure that the particle size was increased and the phase transition of the microgels shifted toward larger temperature regions of the hydrodynamic diameter. FT-IR spectroscopic data of the swelled microgel showed that the free OH stretching band intensity of the COOH segments was enhanced by the exposure, but the band intensity returned to its original level without the US exposure. This meant that the US stimulus broke hydrogen bonding of the microgel and induced hydration of water in the hydrogel environment. Finally, regeneration of the hydrogen bonds in the microgel was occurred after the US exposure.

Phase separation of poly(acrylonitrile-co-methacrylic acid) in compressed liquid CO(2) resulted in formation of a porous imprinted membrane which preferentially adsorbed uracil (URA). The cross-section of the membrane was observed by SEM, which revealed its porous structure. The mechanical strength of the membrane indicated formation of a rigid matrix with high tensile strength (4.4 N mm(-2)). The imprinted membranes bound highly selectively to URA (12.8 micromol g(-1)) but binding to dimethyluracil (DMURA), thymine, and cytosine was less (0.7, 0.8, and 0.9 micromol g(-1), respectively). When DMURA was similarly used to prepare an imprinted membrane in liquid CO(2) there was less binding of DMURA to the imprinted membrane obtained. The URA-imprinted membranes were evaluated by IR spectroscopy before and after URA extraction. The results indicated that hydrogen bonding was the mechanism of binding of URA to the imprinted membrane. Competitive binding studies were performed with binary mixtures of URA and its analogues. The URA-imprinted membrane enabled good separation of URA from cytosine, DMURA, and thymine, with separation factors of 3.0, 3.8, and 2.5, respectively. It was confirmed that the compressed liquid CO(2) contributed to efficient formation of template substrate sites in the URA-imprinted membrane.

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Crosslinked hydrogels made of poly(vinylphosphonic acid-co-N,N 0 -methylenebisacrylamide) (P(VPAco-MBAA)) and poly(vinylphosphonic acid-co-ethyleneglycol diacrylate) (P(VPA-co-EGDA)) were prepared by using precipitation polymerization in water medium. A comparison research was made between the resultant hydrogels containing different loads of vinylphosphonic acid segments when N,N 0 -methylenebisacrylamide (MBAA) or ethyleneglycol diacrylate (EGDA) were used as comonomers. Morphological observations indicated that the resultant copolymer appeared as a fine powder at low VPA loadings and strongly aggregated at the high loadings; especially, a copolymer containing 63 mol % of VPA segments in P(VPA-co-MBAA) was observed to have a flake-shaped appearance in its aggregated morphology. The resultant copolymer powders were characterized using FTIR spectroscopy and titrimetric analysis. Also, monomer reactivity ratios, r 1 and r 2 , of VPA and MBAA or EGDA were estimated as 0.06 and 0.98 for VPA and MBAA and 0.05 and 1.82 for VPA and EGDA, respectively. This suggested that a large distribution of MBAA and EGDA was present in the resultant copolymer powders. Their crosslinked PVPA structure presented hydrogel properties having high water uptakes and an absorption mechanism independent from pH of bulk solution. The evidence showed that high VPA loadings could strongly interacted through hydrogen bonds between neighbor VPA segments even in the presence of water.

Molecular imprinted polymer (MIP) microbeads were prepared by emulsion copolymerization of divinylbenzene (DVB) and methacrylic acid (MAA) in the presence of inosine (INO) template and laurylbenzenesulfonic acid (LBSA) as surfactant. The polymerization was carried out at 55 C under ultrasound exposure. The resulting copolymer microbeads, having 0.1-0.4 lm diameter, were observed to have a binding behavior of INO and surfactant to the polymer which was strongly dependent of the bulk pH; for example, at pH 3, 6, and 10 values of binding for INO to the imprinted copolymer were 3.7 lmol/g, 2.1 lmol/g, and 0 lmol/g, respectively.It was found that LBSA surfactant bound to the MIP microbeads similarly depending on pHs. At pH 3, 6, and 10, the LBSA values of binding were 23 lmol/g, 1.3 lmol/g, and 4.8 lmol/ g. It was also noted that the surfactant binding was enhanced in the presence of the INO template. This demonstrated that a cooperative binding with the surfactant was cooperatively occurred in the presence of INO.