In this work, a novel model that links the macroscopic contact angle, the system temperature and the surface tension is introduced. This model considers that the thermocapillary fluctuations on the droplet surface extend to the triple line and they interact with the solid substrate. The self-affine pinning of this triple line against a solid substrate is modelled with an homogeneous spatial distribution of potential wells. The introduction of a topological dimension in the equations yields a unified model that covers normal wetting (liquid droplets on smooth surfaces) but also Cassie-Baxter and Wenzel states on natural surfaces. The model also encompasses the transition to complete wetting. Results are compared to those obtained using the classical Van Oss partitionning method based on static contact angle measurement on a PTFE surface.

Temperature-dependence of the static contact angle: a universal scaling law covering ideal cases, roughness effects and the transition to total wetting

ACS Spring Meeting 2021

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