Novel applications of thermally controlled microbubble driving system

Novel applications of microbubble migration controlled by microheaters are proposed and demonstrated. One is a liquid-film-type motor/conveyer. Vapor or gas bubbles in the cavities on rotor are driven based on Marangoni effect caused by the microheaters on stator. The other is a "valve-less" valve, which is made of in-line microheaters at an intersection of microchannels, where a microbubble moves according to the thermocapillary force and shuts-off liquid flow due to its surface hardness with no mechanical part. With the developments of these new devices, the mechanisms of heat transfer and fluid motion around the microbubble are discussed.