Production and analysis of stable microfluidic devices with tunable surface hydrophilicity via the in-situ tertiary-amine catalyzed Michael addition of a multifunctional thiol to a multifunctional acrylate

Poly(dimethylsiloxane) (PDMS) is one of the dominant polymeric hydrophobic materials that has been widely used in microfluidic devices. Here, we employed amine-catalyzed thiol-acrylate chemistry with hydrophilic and fluorinated acrylates to produce a wide range of stable hydrophilic materials without use of expensive instrumentation or complicated techniques to activate surfaces. The process involved the Michael addition of a secondary amine to a multifunctional acrylate followed by bulk modification of the polymer network with monofunctional acrylates. The surface energies of the bulk modified thiol-acrylate thermoset materials were more stable and tunable than the surface energies of physically/chemically treated PDMS. The surface energies of these microfluidics devices were programmed to have water contact angles ranging from highly hydrophilic (similar to 11 degrees) to slightly hydrophilic (similar to 85 degrees). A complete microfluidic device was fabricated illustrating the potential material as an alternative of PDMS to be used as microfluidics devices.