Characterization of Inkjet-Printed Digital Microfluidics Devices
Shiyu Chen1, Zhidong He1, Suhwan Choi1
1Department of Mechanical Engineering, University of Washington, Seattle, WA 98195, USA.
Sensors (Basel, Switzerland)
|April 30, 2021
Summary
Inkjet printing offers a low-cost method for fabricating digital microfluidics (DMF) devices. Kapton dielectric coatings provide superior robustness compared to PMMA for DMF applications.
Area of Science:
- Microfluidics
- Materials Science
- Electrical Engineering
Background:
- Digital microfluidics (DMF) devices are crucial for point-of-care testing, typically using printed circuit board (PCB) substrates.
- Inkjet printing presents a cost-effective and rapid alternative for DMF circuit fabrication, enabling faster design iterations.
Purpose of the Study:
- To demonstrate a cleanroom-free fabrication process for low-cost inkjet-printed DMF circuits.
- To compare the performance of Kapton and polymethyl methacrylate (PMMA) as dielectric coatings in DMF devices.
Main Methods:
- Inkjet printing was used to fabricate DMF circuits.
- Kapton and PMMA were evaluated as dielectric layers, measuring minimal droplet actuation voltage and frequency.
- Dielectric breakdown characteristics were assessed for both materials.
Main Results:
- A minimum actuation voltage of 5.6 V was observed for PMMA (0.2 μm) with a 0.17 μm hydrophobic layer.
- PMMA exhibited significant dielectric breakdown issues above 10 V.
- Kapton-based DMF devices demonstrated superior robustness, withstanding actuation voltages up to 100 V.
Conclusions:
- Inkjet-printed DMF circuits offer a viable low-cost fabrication route.
- Kapton is a more robust dielectric material for DMF applications compared to PMMA, especially at higher voltages.
