“Schizophrenic” Micellization of Poly(Acrylic Acid)-B-Poly(2-Dimethylamino)Ethyl Methacrylate and Responsive Behavior of the Micelles

Abstract

The well-defined block polyampholyte poly(acrylic acid)-b-poly(2-dimethylamino)ethyl methacrylate (PAA-b-PDMAEMA) was synthesized by sequential atom transfer radical polymerization (ATRP) using protected group chemisty. The block polyampholyte exhibited so-called “schizophrenic” micellization behavior at different pH values. The PAA-core micelles, PDMAEMA-core micelles, and a kind of polyeletrolyte complex were formed in acidic pH (pH < 4.5), basic pH (pH > 9.0), and neutral pH region (5.5–8.5), respectively. The temperature responsive behaviors of the micelles and the complex formed in neutral environment were studied in detail via dynamic light scattering (DLS) and UV-vis transmittance. Salt effect on the temperature responsive behavior was also discussed.[Supplementary materials are available for this article. Go to the publisher's online edition of Soft Materials or http://pubs.acs.org for the following free supplemental resource(s): Synthesis of PtBA-b-PDMAEMA, 1H NMR spectra of block copolymer and TEM image of block copolymer at aqueous solution with NaCl]”