Impact of substrate elasticity on contact angle saturation in electrowetting
| Autor: | Periklis Papadopoulos, Ioannis E. Markodimitrakis, Nikolaos T. Chamakos, Dionysios G. Sema, Athanasios G. Papathanasiou |
|---|---|
| Rok vydání: | 2021 |
| Předmět: |
Materials science
02 engineering and technology General Chemistry Dielectric 021001 nanoscience & nanotechnology Condensed Matter Physics 7. Clean energy 01 natural sciences Physics::Fluid Dynamics Contact angle Chemistry Electric field 0103 physical sciences Electrowetting Wetting Composite material Elasticity (economics) 010306 general physics 0210 nano-technology Saturation (chemistry) Voltage |
| Zdroj: | Soft Matter |
| ISSN: | 1744-6848 1744-683X |
| DOI: | 10.1039/d0sm02281k |
| Popis: | The electrostatically assisted wettability enhancement of dielectric solid surfaces, commonly termed as electrowetting-on-dielectric (EWOD), facilitates many microfluidic applications due to simplicity and energy efficiency. The application of a voltage difference between a conductive droplet and an insulated electrode substrate, where the droplet sits, is enough for realizing a considerable contact angle change. The contact angle modification is fast and almost reversible; however it is limited by the well-known saturation phenomenon which sets in at sufficiently high voltages. In this work, we experimentally show and computationally support the effect of elasticity and thickness of the dielectric on the onset of contact angle saturation. We found that the effect of elasticity is important especially for dielectric thickness smaller than 10 μm and becomes negligible for thickness above 20 μm. We attribute our findings on the effect of the dielectric thickness on the electric field, as well as on the induced electric stresses distribution, in the vicinity of the three phase contact line. Electric field and electric stresses distribution are numerically computed and support our findings which are of significant importance for the design of soft materials based microfluidic devices. Soft and thin dielectrics favor contact angle saturation in electrowetting. Experiments are supported by detailed numerical computations of the electric field and stress distribution. |
| Databáze: | OpenAIRE |
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