Light-Responsive Shape Memory Polymer Network Containing Azobenzene: Shape Manipulation, Mechanical Regulation, and Intelligent Lubrication

Light-responsive materials have garnered significant attention in fields such as robotics and actuators due to their flexibility in remote and localized control, presenting immense application potential. In this work, we demonstrate intelligent responsive applications through the introduction of a liquid crystal network formed by azobenzene, showcasing photoinduced shape memory performance, light-reversible tribological behavior, and thermally driven force modulation. By copolymerizing the liquid crystal monomer 1,4-bis-[4-(6-acryloyloxyhexyloxy)benzoyloxy]-2-methylbenzene with a functional azobenzene monomer, we can adjust the cross-linking density and mechanical properties of the yield liquid crystal elastomer networks (LCNs) by varying the azobenzene content, resulting in a high-strength elastomer with a tensile strength of 23.6 MPa. The unique microstructure of this material, which readily crystallizes at low temperatures, allows LCN-20 to generate a high actuating stress of ∼5.6 MPa when cooled from 15 °C to −45 °C, significantly expanding its potential as an actuator. The presence of azobenzene enables photoisomerization, imparting reversible changes in the surface contact angle and modulus. Additionally, the photothermal effect of azobenzene facilitates light-controlled shape memory performance. By integrating the tunable surface and mechanical properties, the LCNs demonstrate reversible tribological switching upon UV–visible light irradiation, significantly expanding their potential as smart adaptive materials. This work provides a heuristic perspective for designing multiresponsive and performance-adjustable materials.