光响应性水凝胶的分子设计和仿生驱动.

Hydrogels are a type of high-water content and crosslinked polymer networks, which can produce a volumetric expansion or contraction through a water absorption or loss process under external environmental stimulation. Due to their good biocompatibility and adjustable mechanical properties, hydrogels have attracted wide attentions and have been extensively applied in the fields of tissue engineering, biomimetic deformation and intelligent actuation. Light is a noncontact, fast switching and high spatiotemporal resolution stimulus, and therefore is used to regulate the macroscopic structure and properties of hydrogels through photothermal effects, photochemical reactions or photoisomerization. Among them, photoisomerization of molecular switches has a broader application potential because of its advantages of mild irradiation conditions and high reversibility. In this review, we summarize the state-of-the-art of photoresponsive hydrogels based on molecular photoisomerization, emphasizing the principle of molecular design as well as applications in biomimetic actuation, and eventually address their perspectives and challenges in the future development. [ABSTRACT FROM AUTHOR]