Regensburg 2010 – scientific programme

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DY: Fachverband Dynamik und Statistische Physik

DY 9: Granular Matter/ Contact Dynamics I

DY 9.6: Talk

Tuesday, March 23, 2010, 11:15–11:30, H47

Temperature-induced liquid bridges — •Christoph Gögelein, Martin Brinkmann, Matthias Schröter, and Stephan Herminghaus — MPI für Dynamik und Selbstorganisation, Bunsenstr. 10, 37073 Göttingen

We all now that if we add a small amount of water to a heap of sand, the medium becomes paste-like since some of the grains get connected by liquid bridges. These bridges act as little springs between neighbouring particles stiffening the material. With wet sand, we can easily sculpture, for example, a sand castle [1]. We use a non-Brownian suspension of micrometer-large glass spheres dissolved in a critical binary liquid mixture to study the the physical properties of wet and dry granular matter. The suspending water-lutidine mixture exhibits a lower critical point leading to a phase separation slightly above ambient temperature. Within the two-phase region the water-rich phase wets the glass spheres and liquid bridges are formed between close-by particles. Thus, we can switch the bridges on by increasing temperature. We observe the temperature-induced formation of liquid bridges using a confocal microscope and calculate the cohesive force from bright field images.

[1] M. Scheel, et al., Nature Materials 7, 174 (2008)