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Study of Phase Separation of Poly( N ‐isopropylacrylamide‐ co ‐styrene) Aqueous Solutions with Rayleigh Scattering Technique
Author(s) -
Yi Guibin,
Zhu Zhenghong,
Wang Fei,
Chen Xudong,
Yang Jin,
Huang Yunwei
Publication year - 2011
Publication title -
chinese journal of chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.28
H-Index - 41
eISSN - 1614-7065
pISSN - 1001-604X
DOI - 10.1002/cjoc.201190177
Subject(s) - chemistry , copolymer , aqueous solution , styrene , polymerization , phase (matter) , emulsion polymerization , polymer chemistry , rayleigh scattering , poly(n isopropylacrylamide) , analytical chemistry (journal) , chemical engineering , polymer , chromatography , organic chemistry , optics , engineering , physics
A thermally sensitive copolymer, poly( N ‐isopropylacrylamide‐ co ‐styrene) [P(NIPAM‐ co ‐St)] ( M n 9.5×10 5 g/mol and M w / M n 1.51) was synthesized by soap‐free emulsion polymerization. The phase separation of the copolymer in water was investigated by Rayleigh scattering (RS) technique. The RS spectra revealed the transition of molecular conformation and the aggregation of molecular chains in the course of phase separation. The coil‐to‐globule and globule‐to‐coil transitions of P(NIPAM‐ co ‐St) chains were found in one heating‐and‐cooling cycle. By means of Avrami formula, apparent activation energy of phase separation of P(NIPAM‐ co ‐St) aqueous solutions was estimated. Moreover, a model was proposed to describe the phase separation process.