Recent advances of biomass-based smart hydrogel Actuators: A review.

• A review about classification, characteristics and applications of biomass-based smart hydrogel actuators is presented. • Categories and common preparation processes of biomass-based smart hydrogel actuators are introduced. • Different stimulation responses of biomass-based smart hydrogel actuators are elaborated. • Applications of biomass based smart hydrogel actuators in different aspects are summarized. Due to the characteristics of a large amount of water inside, good softness, and ability to respond to various external stimuli, smart hydrogels have attracted great attention in the field of soft actuates and soft robots, and have a wide range of application prospects in the biomedical field. Biomass materials are biodegradable, renewable, environmentally friendly and non-toxic, and the hydrogels prepared based on biomass materials have typical anisotropy, biocompatibility and biodegradable characteristics, which have become a hot spot for the development of smart actuators. In this review, we briefly classify and introduce biomass-based smart hydrogel actuators, discuss their common actuating modes, and summarize their applications in soft actuators and soft robots. Finally, we discussed the key issues and challenges in the future development of biomass-based hydrogel actuators and made prospects. [ABSTRACT FROM AUTHOR]