Rationally designed hyperbranched azopolymer with temperature, photo and pH responsive behavior?

Polymer Chemistry Pub Date: 2018-04-30 DOI: 10.1039/C8PY00472B

Abstract

A new azobenzene-containing hyperbranched polymer, HPAzoAMAM-star-EG3, was efficiently synthesized via two-step Michael addition polymerization. The proposed polymer could self-assemble into uniform large compound micelles (LCMs) that show temperature, photo and pH responsiveness. The LCMs turned into pancake-like platelets when cooled to ca. 20 ?C and their spherical morphology was restored at temperatures higher than 30 ?C. Upon irradiation with linear polarized light (LPL), the LCMs were elongated into short spindles. The photo-isomerization rate could be accelerated by loading silver nanoparticles (SNPs) into the LCMs via direct reduction. Moreover, the LCMs broke down into a much smaller size when the pH value was less than a critical point, ca. 3.90, whereas they remained stable at higher pH values. The combined advantages of the facile synthesis, hyperbranched structure, uniform morphology of assembly and multi-responsiveness endow the polymer with promising potential for applications in controlled release and smart deformable micro/nanostructures.

Graphical abstract: Rationally designed hyperbranched azopolymer with temperature, photo and pH responsive behavior
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