Biotech, Biomaterials and Biomedical: TechConnect Briefs 2015Biotech, Biomaterials and Biomedical TechConnect Briefs 2015

Micro, Nano & Bio Fluidics Chapter 4

Low-cost spin-coatable, Transferable, and High-k Ion Gel Dielectric for Flexible Eletrowetting

V. Narasimhan, V. Sanjairaj, S-Y Park
National University of Singapore, Singapore

pp. 230 - 233

Keywords: electrowetting, ion gel

Electrowetting-on-dielectric (EWOD) is an emerging liquid-handling technology, enabling the wettability modulation of a liquid on a solid surface with an applied electric field. Recently, EWOD has been attractively used on flexible substrates to show potential applications of electronic display, lab on a chip, and biochemical sensors. To improve EWOD performance, a high-k material such as Si3N4, Al2O3, and Ta2O5 are typically proposed to provide a higher dielectric property than SiO2. However, these materials need expensive and complex vacuum facilities like CDV, PECVD, and sputtering for layer deposition. In addition, the rigidity of the materials renders them impractical for flexible electrowetting applications. Although polymer-based materials such as PDMS, SU-8, and Parylene C have been alternatively used to permit deformability, they are low-capacitance dielectrics that require high operational voltages up to 700 V. Here, we present, for the first time, ion gel as a new high-k dielectric that can be simply fabricated by spin-coating without any expensive vacuum facilities. Our study for EWOD performance indicates that ion gel is capable of lowering operational voltage and providing an improved high-k dielectric without bubble generation by electrolysis. Transferring and deformable capabilities of the ion gel layer has been experimentally demonstrated as well.