'Blinking bubble' micropump with microfabricated heaters

A micropump based on the periodic growth and collapse of a single vapor bubble in a microchannel is described. The bubble is generated by a vacuum-deposited platinum heater on a quartz chip. The pump is formed by bonding to the chip an acrylic cover with input and output ports in which a 125 mu m channel is machined. Pumping rates on the order of 10 mu l min(-1) were obtained. In the absence of a complete theory for the device, the data are interpreted and rationalized on the basis of simple physical arguments. In particular, optimal performance conditions are derived. The micropump described here is simple in concept and realization and robust, as it does not have mechanical moving parts. A bi-directional pump can easily be built by providing two heaters.