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CPP: Fachverband Chemische Physik und Polymerphysik

CPP 34: Poster: Wetting, Micro and Nano Fluidics

CPP 34.19: Poster

Wednesday, March 13, 2013, 16:30–18:30, Poster C

The interplay of capillary rise and vapour phase adsorption in nanoporous Vycor glass — •Sebastian Kiepsch, Nico Bohr, and Rolf Pelster — FR 7.2, Experimentalphysik, Universität des Saarlandes, Campus E2.6, D-66123 Saarbrücken, Germany

The spontaneous imbibition of polar organic liquids, primarily n-decanol (C₁₀H₂₁OH), has been studied for nanoporous Vycor glass by means of dielectric spectroscopy. Vycor glass is an interconnected pore network with pore diameters d_p ≈ 7.5 nm and volume porosity Φ ≈ 35%. For large times t, the imbibition dynamics can be described by the Lucas-Washburn law, h(t) = c_h √t. Here, h denotes the capillary height and the prefactor c_h depends on fluid parameters (viscosity, surface tension) and matrix parameters (porosity, radius ...). However, during the initial phase of the process, a systematic deviation from the square root behaviour occurs. We address the question whether the imbibition dynamics are a simple superposition of capillary rise and concurrent vapour phase adsorption. The time dependence of the latter process is measured in a controlled environment using the same technique.