Berlin 2018 – wissenschaftliches Programm

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CPP: Fachverband Chemische Physik und Polymerphysik

CPP 40: Wetting, Microfluidics and Confined Liquids I (joint session CPP/DY)

CPP 40.7: Vortrag

Mittwoch, 14. März 2018, 11:30–11:45, C 264

Forced dynamic dewetting of structured surfaces: Influence of surfactants — •Günter K. Auernhammer^{1, 4}, Franziska Henrich¹, Dorota Linke¹, Hans Martin Sauer², Edgar Dörsam², Steffen Hardt³, and Hans-Jürgen Butt¹ — ¹MPI Polymer Research, Mainz, Germany — ²TU Darmstadt, IDD, Germany — ³TU Darmstadt, Nano- und Mikrofluidik, Germany — ⁴IPF, Dresden

We investigate dynamic dewetting on structured surfaces. The focus lies on the interplay between surface structure and surfactants concentration in forced dewetting. The structured surfaces are printing plates for gravure printing with different sizes of the gravure cells. These plates were mounted on a rotating horizontal cylinder that is half-immersed in an aqueous solution of the anionic surfactant sodium 1-decanesulfonate. On the printing plates, structured and unstructured areas were side by side to enable a direct comparison. When rotating the cylinder a liquid meniscus is partially drawn out of the liquid. The moving contact line was pinned on the borders of the gravure cells, leading to a strongly varying receding contact angle. For this reason we compare the height differences of the meniscus on the structured and unstructured area. With increasing size of the gravure cells this height difference increases. By adding surfactant, the height difference for the same surface decreases. We conclude that the surfactant reduces the influence of a structured surface on dynamic dewetting. Characterizing the emptying mechanism of the gravure cells revealed that some liquid is left in the gravure cell.