Operation Frequency of an Exploding Gas Microactuator

An exploding gas actuator uses H2 and O2 nanobubbles produced electrochemically. At some conditions, these nanobubbles merge and explode synchronously due to a combustion reaction. This actuator, with a volume of less than 10 nL, demonstrated excellent properties, but the actuation frequency was restricted to 1 Hz. In this paper, it is shown that the natural actuation frequency has to be as high as 100 Hz, and the reasons for the restricted frequency are analysed. It is found that there exists a threshold frequency, which increases with the chamber size. It reaches a value of 40 Hz for a chamber with a diameter of 1 mm. Above the threshold frequency, a residual gas is collected in the chamber. This gas is identified as air dissolved in the electrolyte. Explosions in the chamber provide conditions for the residual gas to form microbubbles, which are dissolved at a low operation frequency but collected above the threshold value. This study opens up opportunities to increase the actuation frequency of the exploding gas actuator.