Encryptable Electrochromic Smart Windows: Uniaxially Oriented and Polymerized Hierarchical Nanostructures Constructed by Self-Assembly of Tetrathiafulvalene-Based Reactive Mesogens

Abstract

Tetrathiafulvalene (TTF)-based reactive mesogens (TTF-Eand TTF-T)are synthesized, self-assembled, uniaxially oriented, and polymerizedfor the development of encryptable electrochromic smart windows. Electrochemicaland spectroscopic experiments prove that the self-assembled TTF mixture(TTFM, TTF-E:TTF-T = 1:1) can reversibly switch the absorption wavelengthof the TTF chromophore according to the redox reactions. Based onthe identification of the phase transition and crystallographic structure,uniaxially oriented hierarchical nanostructures are easily constructedon the macroscopic area by simple coating and a self-assembly process.Subsequent polymerization of hierarchical nanostructures of TTFM significantlyenhances thermal and mechanical stabilities and makes it possiblefor them to be fabricated as an electrochromic device. The angularlydependent correlation between the anisotropy of mesogens and the linearlypolarized light allow us to demonstrate TTFM as smart windows capableof various optical security applications, including privacy protectionand information encryption.