Regensburg 2019 – wissenschaftliches Programm
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CPP: Fachverband Chemische Physik und Polymerphysik
CPP 20: Wetting, Fluidics and Liquids at Interfaces and Surfaces (joint session CPP/DY)
CPP 20.11: Vortrag
Dienstag, 2. April 2019, 12:30–12:45, H13
Wetting of n-Alkane Nano-Patterns: Evidence of Macroscopic Line Tension Effects and Adaptive Wetting — •Diego Diaz1, Tomas P. Corrales2, Maria J. Retamal3, Marcelo Cisternas1, Nicolas Moraga1, Rodrigo Catalan1, Mark Busch4, Patrick Huber4, Marco Soto-Arriaza3, and Ulrich G. Volkmann1 — 1Institute of Physics and CIEN-UC, P. Univ. Catolica de Chile, Santiago, Chile — 2Department of Physics, UTFSM, Valparaiso, Chile — 3Faculty of Chemistry and CIEN-UC, P. Univ. Catolica de Chile, Santiago, Chile — 4TUHH, Hamburg, Germany
We present a wetting study of silicon samples coated with a single layer of n-alkane molecules self-assembled perpendicular to the surface by velocity-dependent dip-coating. The contact angle was measured with 2 microliters of ultrapure water for different n-alkane surface coverages. The results of the apparent contact angle versus coverage can be grouped in two regimes that depend linearly on coverage. This can be described by the Cassie wetting model along with the consideration of line tension effects. The two wetting regimes are characterized by two line tensions representing distinct alkane monolayer morphologies, i.e. dentritic and stripe patterns resulting from different dip-coating velocities. During drop evaporation, there is a restructuring of the alkane monolayer structure which could be related to adaptive wetting. Acknowledgements: FONDECYT Nos. 3160803 (MJR), 1180939 (UGV) 1171047 (MSA) and 11160664 (TPC), CONICYT Fellowship (MC) and CONICYT-PIA ACT 1409.