Regensburg 2019 – scientific programme

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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: Talk

Tuesday, April 2, 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.