Abstract
This paper describes the effect of the contact angle hysteresis caused by the adhesion between the liquid droplet and the solid surface on the threshold voltage for droplet transport in three different ground-type electrowetting configurations. It was found that the threshold voltage equals the hysteresis voltages in both single-plate and twin-plate configurations and the square root of 2 times the hysteresis voltage in the two-plate configuration by analyzing the contact angles at electrowetting threshold theoretically. The fabricated devices using 2.5 um thick polyimide ( r = 3.3) as the dielectric layer and thin Teflon AF as the hydrophobic layer ( 0 = 116 and = 4-6) showed the threshold voltages for droplet transport initiation of 28, 40 and 28 V in the single-plate, two-plate and twin-plate devices, respectively, and the threshold voltages for stable droplet transport of 35, 50 and 35 V, respectively. All the results are in very good agreement with theoretical values.
| Original language | English |
|---|---|
| Pages (from-to) | 2105-2111 |
| Number of pages | 7 |
| Journal | Journal of Adhesion Science and Technology |
| Volume | 26 |
| Issue number | 12-17 |
| DOIs | |
| Publication status | Published - 2012 Sept 1 |
Bibliographical note
Funding Information:This work was supported by Seoul R&BD Program (No. 10920) and by the National Research Foundation of Korea (NRF) grant funded by the Korea government (MEST) (No. K20902001448-10E0100-03010 and NRF-2010-355-D00024).
Keywords
- Digital microfluidics
- adhesive friction
- contact angle hysteresis
- droplet transport
- electrowetting
- threshold voltage
ASJC Scopus subject areas
- General Chemistry
- Mechanics of Materials
- Surfaces and Interfaces
- Surfaces, Coatings and Films
- Materials Chemistry