Microfluidic oscillator using vapor bubble on thin film heater

Abstract

A novel microfluidic actuator of heater-bubble system is proposed, where a nucleated microbubble rolls right and left repeatedly without any periodic external signal, which means that such bubble motion is applicable as an oscillator. This actuation principle is based on the Marangoni effect and boiling heat transfer, which work as the attraction and release mechanisms respectively. Experimental results show that the frequency of this automatic oscillation is dependent on both bubble size and heater geometry. The surrounding liquid temperature is also a key factor for the feasibility of such motion. The major microfluidic phenomena realizing this actuator are analyzed and discussed qualitatively.