  Pumping fluids without an aid of an external power source are desirable in a
number of applications ranging from a cooling of microelectronic circuits to
Micro Total Analysis Systems (micro-TAS). Although, several microfluidic pumps
exist, yet passive micropumps demonstrate better energy efficiency while
providing a better control over a pumping rate and its operation. The fluid
pumping rate and their easy maneuverability are critical in some applications;
therefore, in the current work, we have developed a leaf-mimicking micropump
that demonstrated ~6 fold increase in a volumetric pumping rate as compared to
the micropumps having a single capillary fluid delivery system. We have
discussed a simple, scalable, yet inexpensive method to design and fabricate
these leaf mimicking micopump. The microstructure of the micropumps were
characterised through scanning electron microscopy and its pumping performance
(volumetric pumping rate and pressure head sustainence) were assessed
experimentally. The working principle of the proposed micropump is attributed
to its structural elements; where branched-shaped microchannels deliver the
fluid acting like veins of leaves while the connected microporous support
resembles mesophyll cells matrix that instantaneously transfers the delivered
fluid by a capillary action to multiple pores mimicking the stomata for
evaporation. Such design of micropumps will enable an efficient delivery of the
desired volume of a fluid to any 2D/3D micro/nanofluidic devices used in an
engineering and biological applications.
