Electrochemical characterization of ionogel actuators

Abstract

Ionogels (IOs) have been characterized by Electrochemical Impedance Spectroscopy (EIS) using gold interdigitated electrodes (Au-IDEs). Poly(N-isopropylacrylamide) (pNIPAAm) was photopolymerized in the presence of two ionic liquids (ILs), 1-ethyl-3-methylimidazolium ethyl sulfate [C2mIm][EtSO2] (1) or trihexyltetradecyl-phosphonium dicyanamide [P6,6,6,14][DCA] (2). The properties of the ILs are directly transferred to the IO and differences in Charge Transfer Resistance (Rct) were measured between the swelling and drying states. It was observed that IO-2 traps water molecules in a stronger way than IO-1, therefore its swollen state is more stable. Additionally, the resulting porosity was analyzed and related with their ability to accommodate water. These studies ensure a better understanding of the actuator behavior of the IOs.