Regensburg 2013 – scientific programme

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CPP: Fachverband Chemische Physik und Polymerphysik

CPP 30: Poster: Focus: Wetting on smooth and rough surfaces: From spreading to superhydrophobicity

CPP 30.9: Poster

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

Transparent silica nano- and microchannels for microfluidic devices — •Lena Mammen, Xu Deng, Kathrin Friedemann, Frank Schellenberger, Periklis Papadoupolos, Daniel Crespy, Hans-Jürgen Butt, and Doris Vollmer — Max Planck Institute for Polymer Research, Mainz, Germany

Nano- and microchannels are attractive model systems for fundamental studies like filling kinetics, diffusion processes or transport phenomena. In this work transparent nano- and few-micrometer-sized silica channels were prepared by coating different polymer fiber templates with silica performing a modified Stöber synthesis and subsequent removal of the organic material by calcination. As templates either PVA or polystyrene electrospun or spider silk fibers were used. The channels have a circular cross-section with uniform diameter and smooth surface. We measured the capillary filling speed of water and glycerol/water mixtures and castor oil using laser scanning confocal microscopy (LSCM) what is a convenient technique to observe the filling velocities close to the channel entrance. By comparing our results with the theoretically predicted values according to the classical Washburn kinetics we found a deviation for small filling times (< 0.1 s) from the power law.