Red-light controlled supramolecular co-assembly transformations of stiff stilbene and donor acceptor stenhouse adduct amphiphiles

Abstract

Amphiphiles are of great interest in the search of biomimicking supramolecular assembly for their assembling into complex and hierarchical structures in aqueous media across multiple length-scale. Incorporations of photoswitching units into amphiphiles provide a means to control the morphology of the resultant assembled structures by light irradiation, which is non-invasive and generally biocompatible. The use of light to induce morphological changes offers several extra merits, including selective excitation of photoswitches by different wavelengths, high temporal- and spatial-resolution. Macroscopic soft materials assembled from donor-acceptor Stenhouse adducts (DASA) amphiphiles (DA) in aqueous media are generally suffered from absorption peak broadening due to aggregation and requires strong white-light irradiation to induce a morphological change. Herein, we provide a new strategy for the restoration of red-light sensitivity of DA in aqueous medium, which requires a co-assembly system of DA with a six-membered fused ring stiff stilbene amphiphile (6SA). This 6SA:DA co-assembly forms supramolecular structures in both microscopic and macroscopic length-scale. Morphological changes of these supramolecular structures can be fine adjusted with red-light irradiation. The structural design, supramolecular assemblies and co-assemblies, and macroscopic scaffolds of photoresponsive SA and DA could enable potential visible-light controlled soft functional materials with improved biocompatibility and photosensitivity.