When droplets evaporate from surfaces, contact line pinning determines both motion and evaporation modes. This project will create surfaces that have no contact line pinning, but control evaporation by structured surfaces.
The Evaporation of droplets on a surface is important in many processes and particularly in heat transfer. It is well known that modes of evaporation in droplets are largely driven by the nature of the contact line pinning on a surface. Slippery Liquid Infused Porous Surfaces (SLIPS) and Slippery Omni-phobic Covalently Attached Liquid-like (SOCAL) surfaces are both surfaces with very low contact line pinning. On these surfaces droplets have been seen to evaporate in the Constant Contact Angle (CCA) mode. This project will use these surface coatings on specifically shaped and designed surfaces to create macro-structures that impart specific control on the way a droplet evaporates.
You will fabricate and test surfaces that control the evaporation of droplets when the surface is perfectly smooth and pinning free. You will test how any underlying structures determine the shape and movement of the droplets during evaporation and condensation. You will create surfaces using photolithographic techniques, as well as more commercially available techniques such as 3D printing. Experiments will be performed using time lapse video observation and drop shape analysis. You will test the ability of these surfaces to control droplets. You will also investigate how structured surfaces change particle flow within the droplets and later move on to consider how surface chemistry can enhance or inhibit evaporation and control.
Work will be conducted within the School of Engineering of the University
Recent Relevant Publication By Supervisor:
Guan, J. H. et al. Evaporation of Sessile Droplets on Slippery Liquid-Infused Porous Surfaces (SLIPS). Langmuir 31, 11781–11789 (2015).
Wells, G. G. et al. Snap evaporation of droplets on smooth topographies. Nat. Commun. 1–7 (2017).
Armstrong, S., McHale, G., Ledesma-Aguilar, R. & Wells, G. G. Pinning-Free Evaporation of Sessile Droplets of Water from Solid Surfaces. Langmuir 35, 2989–2996 (2019).
Guan, J. H. et al. Drop transport and positioning on lubricant-impregnated surfaces. Soft Matter 13, 3404–3410 (2017).
Dr Gary Wells
Minimum entry qualification - an Honours degree at 2:1 or above (or International equivalent) in a relevant science or engineering discipline, possibly supported by an MSc Degree. Further information on English language requirements for EU/Overseas applicants.
Tuition fees + stipend are available for Home/EU students (International students can apply, but the funding only covers the Home/EU fee rate).