Fabrication of porous thin films of block copolymer at the liquid/liquid interface and construction of composite films doped with noble metal nanoparticles

Abstract

Two approaches have been utilized to fabricate thin composite films of amphiphilic polyisoprene-block-poly(2-vinylpyridine) (PI-b-P2VP) doped with silver and gold nanoparticles. Honeycomb and foam structures were obtained at the interfaces between a chloroform solution of the polymer and aqueous solutions of either AgNO₃ or HAuCl₄ through the first route. For the second route, porous thin films were obtained at the interfaces between a chloroform solution of the crosslinked polymer by S₂Cl₂ and pure water, immersed in aqueous solutions of either AgNO₃ or HAuCl₄ to adsorb metal precursors and then treated with KBH₄ aqueous solution to form composite films. The catalytic properties of these films were evaluated by assessing the reduction of 4-nitrophenol by KBH₄ in aqueous solutions. It was found that the metal nanoparticles are unstable enough and fused in the film prepared through the first route while the composite film obtained through the second route exhibited good catalytic performance and was more stable during the catalytic reaction. In addition, the porous polymer film is also expected to adsorb other species to form various functional composites.