Enhanced fatigue resistance and electro-responsive actuation in squid muscle-inspired bionic gel-based soft actuators using PVA and multilayer MWCNT electrode membranes

Squid muscle shows exceptional fatigue resistance and mechanical responsiveness, addressing two major issues in bionic gel–based soft actuators (BGSAs): poor fatigue resistance and limited electro–responsive actuation. Researchers improved these by blending polyvinyl alcohol (PVA) into the gel matrix and adjusting the layers in the multi–walled carbon nanotube (MWCNT) electrode membrane. Experimental results indicated that PVA strengthened the intermolecular forces within the BGSA matrix through hydrogen–bond reinforcement. The addition of 0.3 g of PVA significantly boosted fatigue resistance, mechanical properties, and electrochemical performance, with increases in deflection curvature, operational lifetime, response speed, and output displacement by 50%, 53.3%, 388%, and 44.4%, respectively. Tensile strength rose by 71.4%, resistance dropped by 47.5%, and specific capacitance reached 373.3 nF·cm–2. The five–layer MWCNT electrode membrane improved performance through structural optimization, resulting in a 140% increase in deflection curvature, a 101.8% increase in output displacement, a 268% increase in tensile strength, and a fourfold increase in specific capacitance compared to the control. Future research could investigate a “0.3 g PVA + five–layer MWCNT electrode membrane” hybrid design to enhance performance further.