A capillary system with 1 × 4 microflow switches via a micronozzle–diffuser pump and hydrophobic-patch design for continuous liquid handling

In this paper, we present the design and implementation of a novel 1 × 4 microflow switch without the need of external macro-pumps. This device is a valveless switch by means of the thermal-bubble-actuated method and the area design of the hydrophobic patches on the microchannels. The switch mechanism among different microchannels is controlled by the format and timing of input power that generates thermal bubbles. To enhance the efficiency of the microflow switch, we utilize the nozzle–diffuser structure in front of our microflow switch channels. The experimental results successfully demonstrate the switch function of our microflow switch devices for switching continuous liquid into desired outlet ports based on our hydrophobic-patch design and programmed time-sequence bubble actuation.