Patterning and Mechanochromism of Stretchable Cholesteric Liquid Crystal Elastomers

Cholesteric liquid crystal elastomer (CLCE) is a photonic crystal material with a periodic helical structure that combines unique optical anisotropy with mechanical stimulus-responsive properties, demonstrating broad application prospects in flexible photonic devices. However, the preparation of patterned CLCE still faces challenges. Based on the thiol-Michael addition reaction, thermochromic cholesteric liquid crystalline oligomers (CLCO) with controllable degrees of polymerization and varying chain lengths were synthesized, and the structure-property relationship between their liquid crystal phase structure and structural color was systematically explored. Utilizing the temperature-induced cholesteric-smectic phase transition effect, the structural color of CLCO can be tuned to cover the three primary colors, red, green, and blue, within a wavelength range (Δλ) of 126 nm. Patterned stretchable CLCE films were prepared through local photopolymerization at different temperatures. By further decreasing n（Acrylate）/n（Thiol）, the degree of polymerization of CLCO was enhanced and the crosslinking density of CLCE was reduced, resulting in an increase in its elongation at break to 200% and enabling force-induced color changes across the visible spectrum. This study not only provides new insights into the dynamic regulation and patterning of structural color in CLCE, but also establishes a material foundation for applications in information encryption and anti-counterfeiting.