Rendering SiO2/Si Surfaces Omniphobic by Carving Gas-Entrapping Microtextures Comprising Reentrant and Doubly Reentrant Cavities or Pillars
| Autor: | Eddy M. Domingues, Ahad Syed, Jamilya Nauruzbayeva, Ulrich Buttner, Sankara Arunachalam, Himanshu Mishra, Ratul Das |
|---|---|
| Rok vydání: | 2020 |
| Předmět: |
0303 health sciences
Materials science General Immunology and Microbiology General Chemical Engineering General Neuroscience Nanotechnology 02 engineering and technology 021001 nanoscience & nanotechnology Isotropic etching General Biochemistry Genetics and Molecular Biology law.invention Contact angle 03 medical and health sciences Reentrancy law Metastability Wetting Photolithography Reactive-ion etching 0210 nano-technology 030304 developmental biology Microfabrication |
| Zdroj: | Journal of Visualized Experiments. |
| ISSN: | 1940-087X |
| DOI: | 10.3791/60403 |
| Popis: | We present microfabrication protocols for rendering intrinsically wetting materials repellent to liquids (omniphobic) by creating gas-entrapping microtextures (GEMs) on them comprising cavities and pillars with reentrant and doubly reentrant features. Specifically, we use SiO2/Si as the model system and share protocols for two-dimensional (2D) designing, photolithography, isotropic/anisotropic etching techniques, thermal oxide growth, piranha cleaning, and storage towards achieving those microtextures. Even though the conventional wisdom indicates that roughening intrinsically wetting surfaces (θo 90°. The reentrant and doubly reentrant features in the GEMs stabilize the intruding liquid meniscus thereby trapping the liquid-solid-vapor system in metastable air-filled states (Cassie states) and delaying wetting transitions to the thermodynamically-stable fully-filled state (Wenzel state) by, for instance, hours to months. Similarly, SiO2/Si surfaces with arrays of reentrant and doubly reentrant micropillars demonstrate extremely high contact angles (θr ≈ 150°–160°) and low contact angle hysteresis for the probe liquids, thus characterized as superomniphobic. However, on immersion in the same liquids, those surfaces dramatically lose their superomniphobicity and get fully-filled within |
| Databáze: | OpenAIRE |
| Externí odkaz: |
|