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arXiv · 1305.4471

Annular cracks in thin films of nanoparticle suspensions drying on a fiber

François Boulogne·Ludovic Pauchard·Frédérique Giorgiutti-Dauphiné
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Abstract

We report an experimental study of the crack pattern formed during the drying of a colloidal suspension. A horizontal fiber, which provides a one dimensional, boundary-free substrate, is coated by a film of micronic thickness. The geometry imposes a remarkable annular crack pattern and allowing precise measurements of the crack spacing over a short range of film thickness (between 2 and 10 $μ$m) which varies linearly with the film height. We compare our experimental data with a model proposed by Kitsunezaki which suggests that the variation of the crack spacing with the film thickness depends on the ratio between a critical stress at cracking and a critical stress for slipping on the substrate. By measuring the friction force of the colloidal gels on a hydrophobic surface through a cantilever technique, we can deduce the critical crack stress for these colloidal gels simply by measuring the crack spacing of the pattern.

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François Boulogne, Ludovic Pauchard, Frédérique Giorgiutti-Dauphiné. 2013-05-20. Annular cracks in thin films of nanoparticle suspensions drying on a fiber. https://doi.org/10.1209/0295-5075%2F102%2F39002

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