수용성 블록공중합물에서 산화티탄 분말의 흡착 안정화

Adsorption Stabilization of TiO₂ Particles in Water Soluble Block Copolymers

Micelle formation and adsorption at the TiO₂ interface of a series of polystyrene-polythylene oxide(PS-PEO) block copolymer in aqueous solution was studied using fluorescence probing and small-angle X-ray methods. Further, the stability of aqueous TiO₂ dispersion in the presence of copolymer was investigated by microelectrophoresis, optical density and sedimentation measurements. The dissolution of pyrene as fluorescent probe in aqueous surfactant solution leads to a slow decrease of the I₁/I₃ ratio, as the copolymer concentration increase; I₁ and I₃ are respectively the intensities of the first and third vibrionic peaks in the pyrene fluorescence emission. The behaviour was due to the characteristics of the copolymers and/or to the copolymer association efficiency in water. Moreover, the adsorption at the plateau level increases with decreasing PEO until chain length. The zeta potential of TiO₂ particles decreases with increasing copolymer concentration and reaches a plateau value. Finally, stabilization using block copolymers was more effective with samples having higher weight fractions of PS block.