Stimuli-directed self-organized chiral superstructures for adaptive windows enabled by mesogen-functionalized graphene

Harnessing the distinct characteristics of nanomaterials integrated into host matrices to enable multi-responsive, multi-functional and adapting capabilities of the resulting materials and systems is a thriving research frontier in contemporary nanoscience. Herein, we have judiciously designed and synthesized a mesogen-functionalized graphene (MFG) to facilitate homogeneous dispersion and compatibility with our newly developed liquid crystal (LC) medium. We then demonstrate the concept of an adaptive window system that can autonomously change the optical transparency in response to external multiple stimuli by the fabrication of polymer-stabilized MFG-containing liquid crystalline films with self-organized chiral superstructures. The light transmittance of films could be expediently modulated through the reversible phase transition between the chiral smectic A (SmA*) and the chiral nematic (N*) phases either by environmental temperature change or shining infrared radiation, where the transparent state is furnished by the homeotropic SmA* phase whilst the opaque state results from the focal conic configuration of the N* phase. Importantly, when desired, the opaque state of the devices could be facilely switched into a transparent state by applying an electric field. The research disclosed here provides a convenient and versatile method to dynamically control over the light transmittance through the windows with adaptive behavior in response to multiple environmental cues such as surrounding temperature and infrared exposure from solar radiations, which holds great potential in architectural and automotive applications with intelligent adaptability and energy efficiency.