Bubble-Propelled Microjets: Model and Experiment

Using basic principles of diffusion and reaction, a one-dimensional mass transport model inside a catalytic microjet has been proposed. The effect of microjet geometry on mass transport has been investigated, and its effect on bubble growth and microjet motion has been predicted. Oxygen generation and its flux to one end of the microjet induce nucleation and growth of bubbles. The bubble growth and ejection/burst cause the microjet to move forward. Numerical investigations of the motion related parameters, such as O-2 flux, bubble generation rate and frequency, and average speed of the microjet motors during bubble growth, are found to depend closely on the length and opening radius of the microjet and concentration of H2O2 in the surrounding environment. The predicted results are compared to experimental data obtained from graphene oxide based microjets, and they show good qualitative agreement. These results demonstrate that this simple model could be used to optimize catalytic microjet design.