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

Abstract

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 (~11°) to slightly hydrophilic (~85°). A complete microfluidic device was fabricated illustrating the potential material as an alternative of PDMS to be used as microfluidics devices.