Abstract
The fabrication of microdevices for fluidic control often requires the use of flexible diaphragms in a way that requires cleanroom equipment and compromises performance. We use a CO laser to perform the standard ablative techniques of cutting and engraving materials, but we also apply a method that we call laser placement. This allows us to fabricate precisely-positioned and precisely-sized, isolated diaphragms. This in turn enables the rapid prototyping of integrated multilayer microfluidic devices to form complex structures without the need for manual positioning or cleanroom equipment. The fabrication process is also remarkably rapid and capable of being scaled to manufacturing levels of production. We explore the use of these devices to construct a compact system of peristaltic pumps that can form water in oil droplets without the use of the non-pulsatile pumping systems typically required. Many devices can be fabricated at a time on a sheet by sheet basis with a fabrication process that, to our knowledge, is the fastest reported to date for devices of this type (requiring only 3 h). Moreover, this system is unusually compact and self-contained.
Highlights
Micropumps and microvalves form the basis of many microfluidic applications and are the subject of a number of reviews [1,2,3,4]
Mechanical displacement micropumps (MDMs) are versatile, and peristaltic pumps made from three linked microvalves [1] are readily integrated into microfluidic technologies
Laser-based fabrication has become a powerful technique for the production of microfluidic devices [7,8,19], and the 10.6 μm emission of CO2 lasers provides an effective way of patterning materials, polymers and oxides
Summary
Micropumps and microvalves form the basis of many microfluidic applications and are the subject of a number of reviews [1,2,3,4]. From the early microvalve designs (e.g., [5,6]), such valves and pumps have often been based on the use of a single uniform sheet of the diaphragm material, often of polydimethylsiloxane (PDMS), selectively bonded to a more rigid substrate such as glass or silicon. Materials such as glass and silicon are expensive as compared to polymers, and their fabrication methods tend to rely on cleanroom processes. From its initial demonstration [20] in application to PMMA, CO2 laser patterning has been applied to a very wide range of microfluidic materials such as glass [21], quartz [22], PDMS [23], polytetrafluoroethylene (PTFE [24]), polystyrene (PS [25]), polycarbonate (PC [26]), polyester/polyethylene terephthalate (PET [27]), cyclic olefin copolymer (COC [28]), paper [29] and laminates, both polymeric [30] and co-fired green ceramics [31]
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