A unified model of drag force for bubble-propelled catalytic micro/nano-motors with different geometries in low Reynolds number flows

Motion of catalytic micro/nano-motors with various geometries is mainly determined by the drag force and the propulsion force acting on the motors as they move in low Reynolds number flows. A unified solution of drag force along with drag coefficient for all circular cross-sectional types of micro/nano-motors is derived. The effect of the geometric parameters of a micro/nano-motor, such as the semi-cone angle theta, the ratio xi of length to larger radius, on the drag coefficient is identified. Results provided in this work are useful for optimizing the design and fabrication of catalytic micro/nano-motors, which can be potentially used in biomedical and environmental engineering. (C) 2015 AIP Publishing LLC.