Dresden 2014 – scientific programme

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O: Fachverband Oberflächenphysik

O 36: Posters: Bio/organic Molecules on Surfaces, Graphene, Solid/liquid interfaces, Metal Substrates, Electronic Structure Theory

O 36.71: Poster

Tuesday, April 1, 2014, 18:30–22:00, P1

The evaporation of nanodroplet on a chemically heterogeneous substrate — •Jianguo Zhang, Frédéric Leroy, and Florian Müller-Plathe — Eduard-Zintl-Institut für Anorganische und Physikalische Chemie and Center of Smart Interfaces, Technische Universität Darmstadt, Alarich-Weiss-straße 4, D-64287 Darmstadt, Germany

The pinning phenomenon which causes a constant contact line model (CCL) was often experimentally observed in the evaporation of droplet on a substrate. It is usually believed that the pinning was originated from the substrate*s chemical [1] or/and topographical (rough)[2] heterogeneities. The effect of the topographically heterogeneous surface on the evaporation has been investigated recently by deposited a droplet on a pillared surface[3]. The pinning as well as the CCL model resulted from the roughness was confirmed. However, the chemical heterogeneity effect on the evaporation is still unknown. Here, the evaporation of nanodroplet on a chemically striped substrate has been studied by molecular dynamics simulations. Our results indicate that the chemical heterogeneity can indeed cause pinning and the CCL model when the strip width is larger than 2σ (σ is the atom diameter). Moreover, a slip-jump-stick pattern was observed for the motion of the contact line. The mechanisms for each phase of the pattern have been explored.

[1] P. S. Swain and R. Lipowsky, Langmuir, 14(1998), 6772. [2] P. Lenz and R. Lipowsky, Eur. Phys. J. E 1(2000), 249. [3] X. Chen, R. Ma, et al, Phys. Rev. Lett. 109(2012), 116101.