Synthesis of azobenzene liquid crystal elastomers with photo-thermo synergistic response and reversible bidirectional shape memory

Abstract

This work was designed to investigate the complex shape memory phenomena and explore the potential for bidirectional reversibility within polymer matrices, focusing particularly on dual-response capabilities. A series of shape memory azobenzene liquid crystal elastomers (Dp-LCEs) were synthesized with azobenzene-4,4'-dicarboxylic acid, polycaprolactone, and hexamethylene diisocyanate as the primary raw materials, and triethanolamine was utilized to establish cross-linking points. The structural and thermal properties of these Dp-LCEs were meticulously characterized through Fourier-transform infrared spectroscopy, thermogravimetric analysis, differential scanning calorimetry, and X-ray diffraction techniques. According to the structural and thermal properties test results, they afforded a deep understanding of the material's composition and thermal behavior, essential for optimizing its performance in practical applications. Furthermore, the stretchability, photo-thermal responsiveness, and reversible deformation capabilities of the Dp-LCEs were assessed via stretching tests and by subjecting them to ultraviolet radiation. The findings revealed that the Dp-LCEs demonstrated distinctive photo-thermo-synergy response shape memory features and exhibited outstanding bidirectional reversible shape memory behavior. This research work provided a solid theoretical basis for customization of the advanced multifunctional shape memory materials, potentially paving the way for innovative applications in various fields such as smart textiles, biomedical devices, and adaptive structures. These advancements suggested significant potential for future developments in smart material technologies, particularly in areas requiring precise environmental responsiveness and high-performance adaptability.