Unleashing the power within: Enhancing hydrogel bio-mimetic polymer actuators (HBPA) through sodium alginate crosslinking with cordyceps polysaccharide (CO-PS)

Hydrogel crosslinking varies in properties and stability, with many physiochemical crosslinkers boosting hydrogel performance but raising issues about biotoxicity, sourcing, and compatibility. Cordyceps polysaccharide, from the rare Chinese herb cordyceps, offers antioxidant and anti-cancer benefits without biological toxicity. This study developed a new hydrogel actuating membrane by crosslinking cordyceps polysaccharide with sodium alginate. Hydrogel Bio-mimetic Polymer Actuators (HBPA) were then assembled using non-metallic electrode membranes and tested for electrical actuation properties. A mechanoelectric coupling model was used to study the electrically actuated deflection system of HBPA. Results showed that a crosslinking ratio of 3:5 increased the peak output force density of HBPA to 21.95 mN/g. The actuation speed increased by 8.05 % compared to the basement membrane, while the duty ratio dropped by 80.8 %, significantly enhancing the tremor index. Tremor frequency and amplitude decreased by 43.52 % and 64.88 %, respectively. Electrochemically, specific capacitance grew 3.9 times, resistance fell by 21.7 %, and specific energy rose by 102.42 %. The actuating membrane featured a dense, uniform structure with evenly distributed pores and well-coordinated active groups at the optimal crosslinking ratio. At 4 V, HBPA demonstrated excellent electrical actuation and significant rebound at 0.1 Hz. Moreover, the mechanoelectric coupling model effectively applied to electroactive polymer materials.