Light-activated photodeformable supramolecular dissipative self-assemblies

Abstract

Dissipative self-assembly, one of fundamentally important out-of-equilibrium self-assembly systems, can serve as a controllable platform to exhibit temporal processes for various non-stimulus responsive properties. However, construction of light-fueled dissipative self-assembly structures with transformable morphology to modulate non-photoresponsive properties remains a great challenge. Here, we report a light-activated photodeformable dissipative self-assembly system in aqueous solution as metastable fluorescent palette. Zwitterionic sulfonato-merocyanine is employed as a light-induced amphiphile to co-assemble with polyethyleneimine after light irradiation. The formed spherical nanoparticles spontaneously transform into cuboid ones in the dark with simultaneous variation of the particle sizes. Then the two kinds of nanoparticles can reversibly interconvert to each other by periodical light irradiation and thermal relaxation. Furthermore, after loading different fluorophores exhibiting red, green, blue emissions and their mixtures, all these fluorescent dissipative deformable nanoparticles display time-dependent fluorescence variation with wide range of colors. Owing to the excellent performance of photodeformable dissipative assembly platform, the light-controlled fluorescence has achieved a 358-fold enhancement. Therefore, exposing the nanoparticles loaded with fluorophores to light in a spatially controlled manner allows us to draw multicolored fluorescent images that spontaneously disappeared after a specific period of time.