Photoswitchable thermogelling systems based on a host–guest approach

Abstract

Intelligent regulation of fluid mechanical properties is an enormous challenge. Here we report a photocontrolled thermogelling system that features switchable sol–gel transition in response to light. Such a system is composed of an amphiphilic copolymer appending with charged long alkyl stickers and α-cyclodextrin (α-CD) host units. Temperature can induce reversible threading/dethreading between the α-CD and the alkyl chain, leading to a sol–gel transition. With the introduction of a competitive photoresponsive azobenzene guest, one can remotely modulate the systemic gelation points in a broad temperature window via light irradiation. This class of responsive hydrogel systems would open up a new host–guest approach for the design of logical soft materials.