Poly polymers Responsive surfaces

The temperature response of the poly(NIPAAM)-silica matrices depends drastically on the architecture of the grafted polymer molecules. Surface wettability changes dramatically as temperature changes across the range 32-35°C (corresponding to the phase-transition temperature for NIPAAM in aqueous media) for surfaces where poly(NIPAAM) is terminally grafted either directly to the surface or to the looped chain copoljnner of NIPAAM and N-acryloylhydroxysuccinimide which was initially conpled to the surface. The wettability changes for the... 

A flow injection optical fibre biosensor for choline was also developed55. Choline oxidase (ChOX) was immobilized by physical entrapment in a photo-cross-linkable poly(vinyl alcohol) polymer (PVA-SbQ) after adsorption on weak anion-exchanger beads (DEAE-Sepharose). In this way, the sensing layer was directly created at the surface of the working glassy carbon electrode. The optimization of the reaction conditions and of the physicochemical parameters influencing the FIA biosensor response allows the measurement of choline concentration with a detection limit of 10 pmol. The DEAE-based system also exhibited a good operational stability since 160 repeated measurements of 3 nmol of choline could be performed with a variation coefficient of 4.5%. 

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