Evaporation on Slippery Liquid-like Surfaces
Pinning free evaporation of a droplet occurs from a SLIPS surface (see here). However, the liquid-infused into the surface can be depleted or may risk causing contamination. The same effect can be achieved by covalently-attaching a short chain polymer which has a glass transition temperature below room temperature to the substrate. This creates a nanometric thickness coating with the chain flexibility which endows the surface with liquid-like properties and almost completely removes contact line pinning. A droplet evaporates from this type of surface with its contact area smoothly retracting as its volume reduces, as seen in the video below for evaporation on a slippery omniphobic covalently attached liquid-like (SOCAL) surface.
If we use a hydrophobic PDMS-based liquid-like coating, we can also use an electric field to gain smart control of the contact angle during evaporation.
Publications
- Pinning-Free Evaporation of Sessile Droplets of Water from Solid Surfaces S. Armstrong, G. McHale, R. Ledesma‐Aguilar, G. G. Wells, R. Ledesma-Aguilarand G. G. Wells, Langmuir 35 (2019), 2989–2996
- Evaporation and Electrowetting of Sessile Droplets on Slippery Liquid-Like Surfaces and Slippery Liquid-Infused Porous Surfaces (SLIPS) S. Armstrong, G. McHale, R. Ledesma‐Aguilar and G. G. Wells, Langmuir 36 (2020), 11332–11340