具有宽范围热致变色的胆甾相液晶薄膜OA

Cholesteric liquid crystal elastomers(CLCEs)have attracted considerable attention in smart color-changing materials owing to their unique helical structures and tunable optical responses.However,the thermal color-change range of CLCEs is often limited by the constraints of the polymer network,resulting in a relatively narrow color-change range or requiring elevated temperatures to achieve significant optical variation.In this work,a series of cholesteric liquid crystal films(CLCFs)with varying crosslinking densities were prepared by introducing different amounts of the chain extender EDDET.The influence of crosslinking density on both thermochromic and mechanochromic behaviors was systematically investigated.Increasing the EDDET content effectively reduces the crosslinking density,leading to a significantly broadened thermochromic range.Within 20～100℃,a maximum red shift of 259 nm in the reflection wavelength was observed.Meanwhile,the thermal sensitivity was markedly enhanced,reaching a local maximum of 8.2 nm·℃-1 in the 60～80℃range.Mechanical tests reveal that lower crosslinking density improves the elongation at break and enlarges the strain-induced blue-shift range.After pre-stretching treatment,the thermally induced wavelength shift of the CLCF can be extended to 340 nm,with an average thermal sensitivity of 4.31 nm·℃-1.These CLCFs,featuring a wide thermochromic range and high sensitivity,are promising candidates for smart sensing,information encryption,and wearable optical devices.