A bio-inspired micropump based on stomatal transpiration in plants.

Stomatal transpiration, which is an efficient way to carry water from the roots up to the leaves, can be described by "diameter-law". According to the law, the flow rate induced by micropore transpiration far exceeded that induced by macroscale evaporation, and it can be controlled by opening (or closing) some micropores. In this research, a bio-inspired micropump based on stomatal transpiration is presented. The micropump is composed of three layers: the top layer is a 93 μm-thick PVC (polyvinylchloride) film with a group of slit-like micropores; the second layer is a PMMA sheet with adhesives to join the other two layers together; the third layer is a microporous membrane. Using this pump, controllable flow rates of 0.13-3.74 μl min(-1) can be obtained. This micropump features high and adjustable flow-rates, simple structure and low fabrication cost. It can be used as a "plug and play" fluid-driven unit without any external power sources and equipment.