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CPP: Chemische Physik und Polymerphysik

CPP 8: SYMPOSIUM Nonequilibrium Phenomena in Soft-Condensed Matter

CPP 8.3: Vortrag

Dienstag, 28. März 2006, 14:30–14:45, ZEU Lich

Capillary Rise of Liquids in Mesoporous Silica — •Patrick Huber¹, Klaus Knorr¹, and Andriy Kityk² — ¹Technische Physik, Universität des Saarlandes, D-66041 Saarbrücken — ²Institute for Computer Science, Technical University of Czestochowa, PL-42200 Czestochowa

In order to study liquid flow in restricted geometries we have investigated the capillary rise (spontaneous imbibition) of water and n-alkanes in mesoporous Vycor glass (mean pore diameter 10 nanometer). An analysis of the mass uptake of the porous monoliths versus time, m(t), allows us to determine a characteristic speed of the imbibition process, v_imb, which gives access to the ratio of surface tension σ and viscosity η of the confined liquids: v_imb∼ σ/η. For imbibing water as well as for the n-alkanes investigated (C₈H₁₈-C₃₀H₆₂) we find a √t-Lucas-Washburn type behavior for both the mass uptake and the position of the advancing liquid front. The relative imbibition speeds of the different nanoconfined liquids scale as expected from the ratio of the bulk fluid parameters. The width of the advancing two-phase boundary as a function of time is extracted from light scattering data sets recorded during imbibition. It is discussed with regard to state-of-the art theories of kinetic roughening of such boundaries in disordered media.

[1] M. Alava, M. Dubee, M. Rost, Imbibition in disordered media, Adv. Phys. 53, 83 (2004).