Self-assembly between photoresponsive azobenzene-based dications and thermally sensitive PNIPAM-b-PAA block copolymers in aqueous solution

Abstract

The effect of the photoresponsive azobenzene-based dications (AzoC₁₀N₂O₂²⁺) on the association in thermally sensitive poly(N-isopropylacrylamide)-b-poly(acrylic acid) (PNIPAM-b-PAA) solutions is studied for the first time. The self-assembly of this complexes was measured by dynamic light scattering (DLS), scanning electron microscopy (SEM) and ultraviolet-visible (UV-Vis) spectrum. Results show that the micellar size of this colloidal complexes can be changed by the molar weight of AzoC₁₀N₂O₂²⁺ and reversibly controlled by ultraviolet (UV) light (365 nm) and blue light (455 nm) irradiation. It is the first to use azobenzene-based dications to control the self-assembly of PNIPAM-b-PAA by light irradiation, which enables the selection of appropriate conditions for the micellar properties by light.

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