  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.
