Electrochemical membrane microactuator with a millisecond response time

TL;DR

This paper introduces a novel electrochemical membrane microactuator capable of achieving response times as short as 1 millisecond by utilizing nanobubbles and alternating polarity water electrolysis, enabling high-frequency cyclic operation.

Contribution

The work presents a fast-response electrochemical actuator using nanobubbles and surface reactions, significantly reducing response time compared to traditional actuators.

Findings

Response time as low as 1 ms

Cyclic operation at up to 667 Hz

Membrane displacement up to 90 μm

Abstract

Lack of fast and strong actuators to drive microsystems is well recognized. Electrochemical actuators are considered attractive for many applications but they have long response time (minutes) due to slow gas termination. Here an electrochemical actuator is presented for which the response time can be as short as 1 ms. The alternating polarity water electrolysis is used to drive the device. In this process only nanobubbles are formed. The gas in nanobubbles can be terminated fast due to surface assisted reaction between hydrogen and oxygen that happens at room temperature. The working chamber of the actuator contains concentric titanium electrodes; it has a diameter of 500 um and a height of 8 um. The chamber is sealed by a polydimethylsiloxane (PDMS) membrane of 30 um thick. The device is characterized by an interferometer and a fast camera. Cyclic operation at frequency up to 667 Hz with a stroke of about 30% of the chamber volume is demonstrated. The cycles repeat themselves with high precision providing the volume strokes in picoliter range. Controlled explosions in the chamber can push the membrane up to 90 um.