The shackling photoisomerization effect on self-assembly of azobenzene-containing side-chain homopolymers

Abstract

We herein demonstrate a simple method for designing and synthesizing a series of azobenzene-containing side-chain homopolymers via acyclic diene metathesis polymerization, which display the distinct photoresponsive properties from azobenzene units under alternating irradiation of UV and Vis light. The trans–cis isomerization of azobenzene pendants in one of the homopolymers is limited, thus obtains more trans-isomers in photostationary state, leading to the strong non-covalent π–π interaction between azobenzene pendants that can further drive self-assembly to form the spherical micelles. Moreover, the size of these micelles can be modulated through increasing the molecular weight of homopolymer. Importantly, we can realize the morphological transitions of these micelles from the spherical nanoparticles to shuttle-like nanoaggregates by UV light irradiation. All these results will not only provide a direct and efficient strategy for constructing photosensitive homopolymers, but also expand the self-assembly behaviors and of optical properties azobenzene-containing homopolymers.