Editors' Choice-Development of Screen-Printed Flexible Multi-Level Microfluidic Devices with Integrated Conductive Nanocomposite Polymer Electrodes on Textiles

We present a flexible plastisol-based microfluidic process integrated with conductive nanoparticle composite polymer (C-NCP) electrodes for flexible active microfluidic devices on textile substrates. First, we characterize the stretchability and flexibility of both plastisol films and microfluidic channels. A maximum elongation increase of 37.5% is observed for plastisol films, and a maximum elongation increase of 17.5% is observed for microfluidic channels. We also demonstrate multiple levels of microfluidic channels. Using a new integrated fabrication process, a device that measures the conductivity of fluid between two electrodes is fabricated on a textile and successfully demonstrated and characterized. For this new fabrication process, flexible screen-printable Ag C-NCP, with resistivity of 2.12 × 10−6 Ω·m, is used for device electrodes. Commercial Ag epoxy, with resistivity of 1 × 10−6 ∼ 10 × 10−6 Ω·m, is also used to fabricate a second set of electrodes for comparison. The device is tested with saline solutions at different salt concentrations, and the current through each saline solution is measured at different voltages using both Ag C-NCP electrodes and Ag epoxy electrodes. The current increases linearly for a given voltage as the salt concentration increases, for devices with both Ag C-NCP electrodes and Ag epoxy electrodes.