Mechano-Optical Response Behavior of Polymer-Dispersed Cholesteric Liquid Crystals for Reversible and Highly Sensitive Force Recorders

Force recording (mode, intensity, and orientation) is of great importance in medical rehabilitation, military reconnaissance, space exploration, etc. However, sensors with both reversibility and memorability are still challenging. Here, a reversible sensor based on polymer-dispersed cholesteric liquid crystals (CLC) is developed as a force recorder. Based on the microarea mechano-optical response and finite element analysis, it is confirmed that the mechanochromic response is mediated by the shear deformation of the polymer network and neighboring CLC. There is an obvious quantitative relationship between force intensity, mode, orientation, and the microarea optical response. Moreover, the sensing layer with a lower modulus or thickness is advantageous for a more sensitive device with lower starting pressure. Additionally, the excellent sensitivity and accuracy also highlight the potential applications in force analysis, path tracking, or pattern detection.