High-Efficiency MEMS Electrochemical Actuators and Electrochemical Impedance Spectroscopy Characterization

We present high-efficiency Nafion-coated electrochemical actuators having biocompatible construction suitable for biomedical applications such as drug delivery. High flow rates of up to 141.95 +/- 0.46 mu L/min were achieved (at 13 mA). Nafion coating increased efficiency across all current values tested and prevented current-induced damage to electrodes. The effects of coating thickness, electroplating, actuator orientation, and changes in temperature on actuator performance were studied. Electrochemical impedance spectroscopy is introduced as a tool for characterizing electrodes, quality of electrochemical cleaning, determining surface area activity, and also for understanding the impact of electrolyte coatings, electroplating, and substrate changes on actuator performance. Parylene and polyetheretherketone (PEEK) were investigated as flexible substrate substitutes for soda lime glass. The higher surface roughness of the PEEK substrate compared to glass led to actuators with improved flow rates.