A non-contact thermocapillary driving system at the gas-liquid interface

Non-contact driving technology is widely utilized in various fields due to its advantages of being non-contact, wear-free, and low noise. Thermocapillary driving is an effective approach for non-contact driving at gas- liquid interfaces. When a temperature gradient exists at the gas-liquid interface, it generates a surface tension gradient, which drives the movement of micro-objects at the interface. This research proposes a system that utilizes an array of thermoelectric coolers (TECs) as a heat source, which changes the local temperature at the gas-liquid interface and generates surface tension gradients for driving the movement of interface objects. Experimental results demonstrate that foam particles with a diameter of 0.5 mm can achieve a maximum moving speed of 2.1 mm/s. Furthermore, the system can control multiple micro-objects at the gas-liquid interface for self- assembly. We have also developed a miniature biomimetic water strider robot, this system can drive the robot to perform linear and turning movements at the gas-liquid interface. This system provides a novel approach for non- contact driving of gas-liquid interfaces.