title: Fabrication of composite thin films with microstructures of honeycomb, foam, and nanosphere arrays through adsorption and self-assembly of block copolymers at the liquid/liquid interface.
abstract: The adsorption and self-organization behaviors of two kinds of block copolymers, polystyrene-block-poly(4-vinylpyridine) (PS-b-P4VP) and poly(4-vinylpyridine)-block-polystyrene-block-poly(4-vinylpyridine) (P4VP-b-PS-b-P4VP), at planar liquid/liquid interfaces were investigated. A gel film decorating with honeycomb-like microstructures forms at the liquid/liquid interface between PS-b-P4VP chloroform solution and chloroauric acid aqueous solution. However, foam films were developed when the chloroauric acid aqueous solution was replaced by a chloroplatinic acid solution or a silver nitrate solution. Furthermore, a free-standing film containing the ordered arrays of nanospheres appeared at the liquid/liquid interface between P4VP-b-PS-b-P4VP chloroform solution and chloroauric acid aqueous solution. The formation of these microstructures was attributed to the adsorption of polymer molecules, combining with inorganic ions and the self-assembly of the composite species at the interface. The doped metal ions and complex ions were transformed to metal nanoparticles after further treatment. This is a facile and convenient method to prepare polymer/inorganic nanoparticle composites. These results also indicate the great influences of the polymer structures and the inorganic species in the aqueous phases on the self-assembly behaviors of the polymers at the interfaces, the final morphology, and structure of the composites. In addition, the formed thin composite films doped with well-dispersed, homogeneous small noble metal nanoparticles exhibit great and durable catalytic activities for the reduction of 4-nitrophenol (4-NP) by potassium borohydride.
authors.affiliation: Key Laboratory for Colloid and Interface Chemistry of Education Ministry, Shandong University, Jinan 250100, PR China.
authors.forename: Yanan
authors.initials: Y
authors.lastname: Liu
authors.forename: Lifang
authors.initials: L
authors.lastname: Chen
authors.forename: Yuanyuan
authors.initials: Y
authors.lastname: Geng
authors.forename: Yong-Ill
authors.initials: YI
authors.lastname: Lee
authors.forename: Ying
authors.initials: Y
authors.lastname: Li
authors.forename: Jingcheng
authors.initials: J
authors.lastname: Hao
authors.forename: Hong-Guo
authors.initials: HG
authors.lastname: Liu
keywords: Block copolymer; Catalysis; Composite; Liquid/liquid interface; Self-assembly