Polymethyl methacrylate (PMMA)/fluoropolymer bilayer: a promising dielectric for electrowetting applications

• Published in: Journal of materials science Vol. 57; no. 19; pp. 9018 - 9027
• Main Authors: Yedewar, Pranjali G., Wadhai, Sandip M., Sawane, Yogesh B., Banpurkar, Arun G.
• Format: Journal Article
• Language: English
• Published: New York Springer US 01.05.2022; Springer; Springer Nature B.V
• Subjects: Bilayers; Capacitance; Characterization and Evaluation of Materials; Chemistry and Materials Science; Classical Mechanics; Contact angle; Crystallography and Scattering Methods; Electric potential; Electric properties; Fluorine compounds; Fluoropolymers; Focal plane; Materials Science; Polymer Sciences; Polymers; Polymers & Biopolymers; Polymethyl methacrylate; Polymethylmethacrylate; Rapid prototyping; Solid Mechanics; Thickness; Voltage
• ISSN: 0022-2461; 1573-4803
• DOI: 10.1007/s10853-022-07235-3

We present electrowetting (EW) on a Bilayer Dielectric Stack (BDS) made from PMMA polymer and a top layer of fluoropolymer. The effective capacitance of such BDS is inversely proportional to the layer thickness. The EW response was analyzed on distinct BDS surfaces where the PMMA layer thickness was varied from a few nanometers to micrometer, and the top layer thickness was kept fixed at 20 nm. The highest value of the effective capacitance, ε eff  ~ 3, was recorded on a BDS for PMMA layer thickness  d p  ~ 0.8 μm with Fluoropel® thickness  d F  = 20 nm. The BDS surface showed consistent EW response for ac as well as for dc-voltages without any EW hysteresis. As a proof of concept, the BDS was utilized on the conductive electrodes of the liquid lens and successfully achieved the manipulation of the oil-liquid interface leading to the magnification of the object placed at the focal plane. Graphical abstract High change in EW contact angle on PMMA /Fluropel bilayer dielectric stack (BDS) The BDS bilayer- PMMA/Fluoropel with thickness 800 nm/20 nm exhibits effective dielectric constant, ε eff ≈ 3. Faithful EW response for ac-voltage as well as dc-voltage. The BDS is durable and finds application in large scale EW applications.