Dynamic Orthogonal Switching of a Thermoresponsive Self-Organized Helical Superstructure.

Controllable manipulation of self-organized dynamic superstructures of functional molecular materials by external stimuli is an enabling enterprise. Herein, we have developed a thermally driven, self-organized helical superstructure, i.e., thermoresponsive cholesteric liquid crystal (CLC), by integrating a judiciously chosen thermoresponsive chiral molecular switch into an achiral liquid crystalline medium. The CLC in lying state, in both planar and twisted nematic cells, exhibits reversible in-plane orthogonal switching of its helical axis in response to the combined effect of temperature and electric field. Consequently, the direction of the cholesteric grating has been observed to undergo 90° switching in a single cell, enabling non-mechanical beam steering along two orthogonal directions. The ability to reversibly switch the cholesteric gartings along perpendicular directions by appropriately adjusting temperature and electric field strength could facilitate their applications in 2D beam steering, spectrum scanning, optoelectronics and beyond.