Uniformly spaced nanoscale cracks in nanoparticle films deposited by convective assembly
Journal of Colloid and Interface Science
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Weldon, A., Joshi, K., Routh, A., & Gilchrist, J. (2017). Uniformly spaced nanoscale cracks in nanoparticle films deposited by convective assembly. Journal of Colloid and Interface Science, 487 80-87. https://doi.org/10.1016/j.jcis.2016.09.078
Rapid convective deposition is used to assemble nanoparticle coatings from suspension, with controllable thickness. Varying film thickness generates stress-induced linear cracks with highly monodisperse spacing. Film thickness is controlled through mechanical means, suspension volume fraction, and the use of applied thermal gradients. These cracks extend in the deposition direction, and a uniform crack spacing from 2 to 160μm is observed. The nanoparticle film thickness is the relevant length scale for hydrodynamic flow, and films will crack with this spacing, in a characteristic manner to minimize the system energy and capillary stresses. As expected from this energy minimization problem and relevant theory, the correlation between coating thickness and crack spacing is highly linear. Because this process is continuous, continuous cracks have potential as a high-throughput method of fabricating nanoscale channels for microfluidics and MEMS.
capillary pressure, convective deposition, cracks, Darcy flow, drying stresses, hydrodynamic stresses, nanoparticle films
We gratefully acknowledge initial conversations with A. Jagota. In addition, we acknowledge support from the National Science Foundation Scalable Nanomanufacturing Program under Grant No. 1120399.
External DOI: https://doi.org/10.1016/j.jcis.2016.09.078
This record's URL: https://www.repository.cam.ac.uk/handle/1810/264800
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