Photo/heat/electricity/pressure-driven photonic pattern with multimode memory effect

Abstract

The multimode memory effect of cholesteric liquid crystals (CLCs) photonic patterns has promising applications for the development of optical sensors, responsive colour decors, and camouflaging techniques. The present memory pattern is mainly aroused from the elastic effect of the polymer network or bistability of the CLC, it is desired for the development of alternative memory mode in non-polymerizable system, which may be helpful for the recyclable use of LC materials for the expired pattern. There remains a challenge for designing photonic patterns with multimode memory effects in a non-polymerized system owing to the limited availability of responsive materials. Herein, photo/heat/electricity/pressure multimode photonic memory pattern was firstly fabricated from non-polymerized cholesteric LC by mixing host LC E7, axially chiral azobenzene-based molecules (ACAMP), and S-form chiral dopants (S5011) based on the combination of PVA alignment layer and photoisomerization of ACAMP. The formed photonic patterns can be reversibly hidden/reappear by controlling the ambient temperature above/below the isotropic temperature or applying combined stimuli of electricity/pressure. The multi-memory pattern from the non-polymerizable system is friendly-environmental (recyclable use) with the simultaneous colour-change of the pattern and background under external stimulus. This study provides new insights into the development of multiresponsive nanostructures with tailorable functionalities, thus presenting new applications in diverse fields ranging from display technologies to information communication.