文献类型：期刊文献

英文题名：Dual-stimuli responsive behaviors of diblock polyampholyte PDMAEMA-b-PAA in aqueous solution

作者：Xiong, Zhiying[1];Peng, Baoliang[1];Han, Xia[1];Peng, Changjun[1];Liu, Honglai[1];Hu, Ying[1]

机构：[1]E China Univ Sci & Technol, Dept Chem, Key Lab Adv Mat, Shanghai 200237, Peoples R China

年份：2011

卷号：356

期号：2

起止页码：557

外文期刊名：JOURNAL OF COLLOID AND INTERFACE SCIENCE

收录：;EI(收录号：20111013732116);WOS:【SCI-EXPANDED(收录号:WOS:000288527800024)】；

基金：This work was supported by the National Natural Science Foundation of China (Projects Nos. 20806022, 20736002), Program for Changjiang Scholars and Innovative Research Team in University (No. IRT0721), the 111 Project (No. B08021), and the Doctoral Research Foundation (No. 200802510008) sponsored by the Ministry of Education of China.

语种：英文

外文关键词：Diblock polyampholyte; Dual-stimuli response; Lower critical solution temperatures (LCST); Aggregation behavior

摘要：Two poly(2-(dimethylamino)ethyl methacrylate)-b-poly(acrylic acid) diblock copolymers. PDMAEMA(84)-b-PAA(18) and PDMAEMA(50)-b-PAA(18), were synthesized by the atom transfer radical polymerization (ATRP) and their dual-stimuli responsive behaviors to the changes in temperature and pH in aqueous solutions were investigated by UV-vis spectroscopy, dynamic light scattering (DLS), H-1 NMR spectroscopy and surface tension measurement. Different from PDMAEMA(84)-b-PAA(18) solutions where no aggregation is observed between pH 7.0 and 9.5, the PDMAEMA(50)-b-PAA(18) aggregates can exist in this broad pH range due to the hydrophobic interactions among the charge-balanced polyampholyte chains. At high pH, e.g., 11.0, the DMAEMA segments collapse to form the core of micelles due to the hydrophobic property of the de-protonized DMAEMA stabilized with the highly ionized AA segments on the surface of the micelles upon heating. At pH around the IEP, e.g., 9.5, large micelles can be formed in PDMAEMA(84)-b-PAA(18) solution upon heating, just like that at pH 11.0, while PDMAEMA(50)-b-PAA(18) first formed the micelles due to the electrostatic attraction between ionized AA segments and protonated DMAEMA segments, but the aggregation of the micelles was hardly happened upon heating due to the smaller DMAEMA segment. Moreover, LCST can be exactly estimated by surface tension experiment. (C) 2011 Elsevier Inc. All rights reserved.