Drops on a Superhydrophobic Hole Hanging On under Evaporation
| Autor: | Mayur Katariya, Aaron Yin Chun Chan, Xuchuan Jiang, Shufen Wang, Oi Wah Liew, Tuck Wah Ng, Murat Muradoglu, Dwayne Chung Kim Chung, So Hung Huynh |
|---|---|
| Rok vydání: | 2017 |
| Předmět: |
business.industry
Chemistry General Chemical Engineering Drop (liquid) Contact line 02 engineering and technology General Chemistry 010402 general chemistry 021001 nanoscience & nanotechnology 01 natural sciences Article 0104 chemical sciences lcsh:Chemistry Optics Sessile drop technique lcsh:QD1-999 Composite material 0210 nano-technology business |
| Zdroj: | ACS Omega, Vol 2, Iss 9, Pp 6211-6222 (2017) ACS Omega |
| ISSN: | 2470-1343 |
| DOI: | 10.1021/acsomega.7b01114 |
| Popis: | Drops with larger volumes placed over a superhydrophobic (SH) surface with a hole do not fall through unless they are evaporated to a size that is small enough. This feature offers the ability to preconcentrate samples for biochemical analysis. In this work, the influence of pinning on the behavior of drops placed on a 0.1 mm thick SH substrate with a 2 mm diameter hole as they evaporated was investigated. With 16 μL of water dispensed, the sessile drop component volume was initially higher than that of the overhanging drop component and maintained this until the later stages where almost identical shapes were attained and full evaporation was achieved without falling off the hole. With 15 μL of water dispensed, the volume of the sessile drop was initially higher than that of the overhanging drop component but the liquid body was able to squeeze through the hole after 180 s due to the contact line not having sufficient pinning strength when it encountered the edge of the hole. This resulted in the liquid body either falling through the hole or remaining pinned with an oval-like shape. When it did not fall-off, the liquid body had volume and contact angle characteristics for the sessile drop and overhanging drop components that were reversed. In the later stages, however, nearly identical shapes were again attained and full evaporation was achieved without falling off the hole. The effects of pinning, despite the substrate being SH, offer another path toward achieving practical outcomes with liquid bodies without the need for chemical surface functionalization. Similarities and differences could be seen in the behavior of a sessile drop on a SH plate that was inclined at 30° to the horizontal and evaporated. |
| Databáze: | OpenAIRE |
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