Synthesis and micellization of two novel poly(acrylic acid)-based azo polyelectrolytes

COLL 392

Yonghong Deng, Yaobang Li, Yaning He, and Xiaogong Wang. Department of Chemical Engineering and School of Materials Science and Engineering, Tsinghua University, Institute of Polymer Science & Engineering, Chemistry Building, Tsinghua University, Beijing, 100084, China
Study on photo-responsive azo polyelectrolyte micelles has important values both in theoretical exploration and in practical applications. Under proper conditions, azo polyelectrolytes, characterized by random covalently tethering azo chromophores on watersoluble polymeric chains, were observed to form stable micelles. Two novel azo polyelectrolytes were synthesized and the azo polyelectrolyte micelles were prepared. Due to the trans-cis isomerization of the azo chromophores, the polyelectrolyte micelles containing azobenzene-type chromophores exhibited obvious photochromism, while the polyelectrolyte micelles containing the pseudo-stilbene -type azo chromophores showed significant optical-induced birefringence. The micelle formation conditions and influence factors were intensively investigated. Spherical micelles with clear profile and narrow size-distribution were obtained by mixing two azo polyelectrolytes with different hydrophobicity, which provide a new method for the first time to prepare high-quality photo-responsive micelles. These photo-responsive micelles are promising for potential applications in photo-controlled release, electro-optical and photonic devices.