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

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, H-1 NMR spectra of block copolymer and TEM image of block copolymer at aqueous solution with NaCl]