Inexpensive, rapid fabrication of polymer-film microfluidic autoregulatory valve for disposable microfluidics.

This work presents the fabrication of a microfluidic autoregulatory valve which is composed of several layers of thin polymer films (i.e., polyvinyl chloride (PVC), polyethylene terephthalate (PET) double-sided tape, and polydimethylsiloxane (PDMS)). Briefly, pulsed UV laser is employed to cut the microstructures of through grooves or holes in the thermoplastic polymer films, and then the polymer-film valves are precisely assembled through laminating the PDMS membranes to the thermoplastic polymer films through the roll-lamination method. The effective bonding between the PVC film and the PDMS membrane is realized using the planar seal method, and the valve is sandwiched and compressed by a home-made housing to achieve the good seal effect. Then, the flow performances of the prototype valve are examined, and constant flow autoregulation is realized under the static or dynamic test pressures. The long-term response of the valve is also studied and minimum flow-rate decrements are found over a long actuation time. The fabrication method proposed in this work is successful for the low-cost and fast prototyping of the polymer-film valve. We believe our method will also be broadly applicable for fabrication of other low-cost and disposable polymer-film microfluidic devices.