Stable layered photochromic films with visual color switching were developed by stacking spiropyran-modified montmorillonite nanosheets.

The controllable ion transport in the photoreceptors of rodc ells is essentially important for the light detection and information transduction in visual systems. Herein, inspiredb yt he photochromism-regulated ion transport in rod cells with stacking structure, layered ion channels have been developed with av isual photochromic function induced by the alternatei rradiation with visible and UV light. The layered structure is formed by stacking spiropyran-modified montmorillonite 2D nanosheets on the surface of an aluminan anoporous membrane. The visual photochromism resultingfrom the photoisomerizationofspiropyran chromophores reversibly regulates the ion transport through layered ion channels. Furthermore, the cooperation of photochromism and pH value achieves multiple switchable states of layered ion channels for the controllable ion transport mimicking the biological process of the visual cycle. The ion transport properties of these states are explained quantitatively by at heoretical calculation based on the Poisson and Nernst-Plank (PNP) equations.[a] T.