文献类型：期刊文献

英文题名：Formation of nanoscale networks: Selectively swelling amphiphilic block copolymers with CO2-expanded liquids

作者：Gong, Jianliang[1]; Zhang, Aijuan[1]; Bai, Hua[1]; Zhang, Qingkun[1]; Du, Can[1]; Li, Lei[1,3]; Hong, Yanzhen[2]; Li, Jun[2]

机构：[1] College of Materials, Xiamen University, Xiamen 361005, China; [2] College of Chemistry and Chemical Engineering, Xiamen University, Xiamen 361005, China; [3] Key Laboratory for Ultrafine Materials of Ministry of Education, School of Materials Science and Engineering, East China University of Science and Technology, Shanghai 200237, China

年份：2013

卷号：5

期号：3

起止页码：1195

外文期刊名：Nanoscale

收录：EI(收录号：20130515949616)

语种：英文

外文关键词：Block copolymers - Film preparation - Carbon dioxide - Nanotechnology - Polypyrroles

摘要：Polymeric films with nanoscale networks were prepared by selectively swelling an amphiphilic diblock copolymer, polystyrene-block-poly(4- vinylpyridine) (PS-b-P4VP), with the CO2-expanded liquid (CXL), CO2-methanol. The phase behavior of the CO2-methanol system was investigated by both theoretical calculation and experiments, revealing that methanol can be expanded by CO2, forming homogeneous CXL under the experimental conditions. When treated with the CO 2-methanol system, the spin cast compact PS-b-P4VP film was transformed into a network with interconnected pores, in a pressure range of 12-20 MPa and a temperature range of 45-60°C. The formation mechanism of the network, involving plasticization of PS and selective swelling of P4VP, was proposed. Because the diblock copolymer diffusion process is controlled by the activated hopping of individual block copolymer chains with the thermodynamic barrier for moving PVP segments from one to another, the formation of the network structures is achieved in a short time scale and shows "thermodynamically restricted" character. Furthermore, the resulting polymer networks were employed as templates, for the preparation of polypyrrole networks, by an electrochemical polymerization process. The prepared porous polypyrrole film was used to fabricate a chemoresistor-type gas sensor which showed high sensitivity towards ammonia. ? 2013 The Royal Society of Chemistry.