A novel fabrication process to realize a valveless micropump on a flexible substrate

This paper reports, for the first time, on the design, fabrication and testing of a planar valveless micropump, entirely screen printed onto a flexible polyimide (Kapton) substrate using sacrificial, structural, conductive and piezoelectric layers. The sacrificial layer, used to achieve a pump chamber and inlet/outlet channels, is removed using water followed by a 140 ° C heat treatment to evaporate the water from the structure. The fabrication process is analogous to a standard silicon based micro-electro-mechanical system sacrificial process. Applying a sinusoidal AC voltage to the piezoelectric layer drives a flexible membrane which pumps a liquid through the chamber. A maximum flow rate of 38 μl min⁻¹ was achieved using a drive frequency of 3 kHz. (paper)