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CPP: Fachverband Chemische Physik und Polymerphysik
CPP 15: Poster I
CPP 15.2: Poster
Montag, 18. März 2024, 18:00–20:00, Poster C
Effect of Low-Pressure Plasma-Treated Hydrophobic Surfaces on Sliding Water Drop Charge — •Fahimeh Darvish1, Sajjad Shumaly1, Xiaomei Li1, Yun Dong1, MohammadReza Khani2, George Floudas1, Doris Vollmer1, and Hans-Jürgen Butt1 — 1Max Planck Institute for Polymer Research, Ackermannweg 10, D-55128, Mainz, Germany — 2Laser and Plasma Research Institute, Shahid Beheshti University, 1983963113 Tehran, Iran
Slide electrification is the spontaneous separation of electric charges at the rear of water drops sliding over hydrophobic surfaces. This research shows how plasma-treated surfaces affect water sliding electrification. Plasma treatment reduced the contact angles and drop charging. Conversely, 64% higher drop charging was achieved using sheath treatment than to pristine sample. Based on the zeta potential, Kelvin potential, XPS measurements, we attributed the effects of plasma to two processes. First, plasma chemically changed the organic topmost layer, e.g., by oxidation and etching. Secondly, charges were deposited in the topmost layer. The surface top layer charges were less negative after sheath and more negative after bulk plasma treatment. The plasma-treated effect was neutralizable. Despite the presence of a PFOTS thin layer, we discovered that the plasma effect on the substrate governs slide electrification remotely, by using different plasma powers during glass activation prior to silanization. However, the surface roughness and contact angles remained unchanged. We demonstrated that both sheath and plasma treatment increase or decrease slide electrification to almost zero while keeping other surface properties constant.
Keywords: Water contact electrification; Low-pressure plasma treatment; Plasma-sheath; Adaptation; Surface charge neutralization