Slow-release effect of absolute ethanol on electro-mechano-chemical behavior and strengthening mechanism of an electric-responsive biomass paper actuator based on calcium alginate hydrogel

This study focuses on investigating a novel category of paper actuators, aiming to attain a favorable equilibrium between substantial electrically actuated force and extended service lifetime ( T s ) for the soft electric-responsive artificial muscle. Consequently, the present research has developed an Electro-responsive Biomass Paper Actuator (ERBPA) utilizing calcium alginate hydrogel, employing absolute ethanol (CH 3 CH 2 OH) as the slow-release agent, through a straightforward and viable preparation procedure. Moreover, a comprehensive investigation was carried out on the electro-mechano-chemical behaviors and strengthening mechanism of the ERBPA with varying volume fractions of CH 3 CH 2 OH, under the electrical actuation of 4 V DC voltage. The experimental findings revealed a gradual decrease in the density of electrically actuated force, elastic modulus, and yield strength with the increasing volume fraction of CH 3 CH 2 OH. Specifically, at a volume fraction of 30%, these properties reached their respective minimum values of approximately 15.152 mN/g, 6.5 MPa, and 0.0999 MPa. In contrast to the internal resistance ( R g ) of the ERBPA, the specific capacitance ( C p ) and the T s exhibited an initial improvement followed by a reduction, while the rise time ( T r ) demonstrated a positive correlation with the volume fraction of CH 3 CH 2 OH but a negative correlation with the reaction velocity ( V f ). Specifically, at a volume fraction of 25%, C p , T s and T r reached their maximum values of 96.2 mF/g, 1287 s, and 170 s, respectively, whereas R g and V f attained their minimum values of 2.39 Ω and 0.044 mN/g·s, respectively. The slow-release effect of CH 3 CH 2 OH inherently contributed to the protection of certain free Ca 2+ ions, thereby causing a gradual and consistent coordination process with sodium alginate molecules. This, in turn, greatly enhanced the internal structure of ERBPA, resulting in exceptional T s stability and operational performance.