Nanoporous copper as an inexpensive electrochemical actuator responsive to sub-volt voltages

Abstract

Metallic actuator materials have been comprehensively studied during the last twenty years, but the studies have been limited to noble metals to date. Here we report reversible dimensional changes in nanoporous copper made by dealloying an Al-Cu alloy. A strain amplitude of 0.11% is obtained using square wave voltammetry in 5 M NaOH, which is comparable to the values reported for a noble metal such as Pt under electrochemical conditions. The oxide formed on the ligaments is believed to stabilize the mechanical properties during the actuation process. Our findings indicate that nanoporous Cu could be a good candidate material for low-cost electrochemical actuator applications.