Stimuli-driven control of self-assembled radial-lying hierarchical superstructures of chiral nematics by using acoustic waves.

Supramolecular functional helical superstructures are typical structures exhibiting many fascinating properties and performances. In nature, cholesteric liquid crystals (CLCs) are self-assembled soft helical superstructures that display orientation-dependent features of supramolecular helical architectures and have potential scientific applications. The most intriguing applications of CLCs primarily depend on the various orientations of their helical axis. We have successfully manipulated the focal conic into imperfect planar textures by using external acoustic stimuli through a CLC cell treated with a planar alignment layer. However, intense acoustic stimuli induce a thermal effect, disordered CLC structures, and the aggregation of chiral dopants. To tackle this issue, we proposed a new self-assembly approach to control CLC helical superstructures through acoustic stimuli. This method enabled the switch of the initial focal conic texture into a unique self-assemble radial-lying hierarchical superstructure (RLHS) texture, providing high transmission and enabling the maintenance of a permanently steady state even after removing external stimuli. Furthermore, the addition of dichroic dyes confirmed the radial aliment of the RLHS structure by utilizing polarized light absorption features, which highlighted the radially oriented helical axes. The device enables the self-assembly of soft matter, leading to new superstructures with practical applications in anti-counterfeiting and other branches of science.