(650b) Biopolymer-Derived Tough Homogeneous Polyelectrolyte Complexes Hydrogels As the Potential Electro-Responsive Actuators

Homogeneous polyelectrolyte complexes (PEC) hydrogels with excellent biocompatibility made from chitosan and carboxymethylcellulose were prepared in the LiOH/KOH/urea aqueous system through a freeze-thawing method. Following the treatments of sequential chemical and physical cross-linking, the resulting hydrogels with super-tough mechanical strength can operate as fast response actuators under electrical stimulus in salt aqueous solutions. The electromechanical behaviors of the hydrogels are strongly dependent on experimental parameters such as electric voltage, solvent constituents, pH, and ionic strength. It is proposed that the electromechanical deformation of hydrogel originates from a dynamic osmotic equilibrium effect taking place at the interface between the hydrogel and the surrounding medium, which is induced by the migration of ions throughout the gel network. In addition, programmable 3D shape transformations were obtained by using the PEC hydrogel with designed 2D geometric patterns. Moreover, the bending actuation behavior of the PEC hydrogel can propel an adjacent object to move forward. This work paves the way to use biopolymer-derived PEC hydrogels as controllable electromechanical actuators integrated in biomimetic smart systems. Further, this PEC hydrogel has potential to be employed in the design and fabrication of smart soft robotics that can be remotely controlled.