Aix-Marseille University, IUSTI UMR 7343 CNRS, 13013 Marseille, France.
Langmuir. 2013 Aug 13;29(32):9962-6. doi: 10.1021/la401428v. Epub 2013 Jul 31.
In this study of drying water-based nanofluid droplets, we report the influence of surface functional groups and substrate surface energies on crack formation and dry-out shape. These two key parameters are investigated by allowing nanofluids with several functional groups grafted on polystyrene nanoparticle surfaces to dry on various substrates. These experiments result in a variety of regular crack patterns with identical nanoparticle diameter, material, concentration, and drying conditions. We demonstrate that, despite the various patterns observed, the crack spacing/deposit height ratio is constant for similar substrate surface energies and linearly increases with this parameter. Moreover, this study shows that the crack shape is strongly influenced by surface functional groups as a result of particle interactions (depending on the particle surface potentials) and compaction during solvent evaporation.
在这项水基纳米流体液滴干燥的研究中，我们报告了表面官能团和基底表面能对裂纹形成和干燥形状的影响。通过允许几种官能团接枝在聚苯乙烯纳米颗粒表面的纳米流体在各种基底上干燥，研究了这两个关键参数。这些实验导致具有相同纳米颗粒直径、材料、浓度和干燥条件的各种规则裂纹图案。我们证明，尽管观察到了各种图案，但在类似的基底表面能下，裂纹间距/沉积物高度比是恒定的，并且与该参数呈线性增加。此外，这项研究表明，由于颗粒相互作用（取决于颗粒表面电势）和溶剂蒸发过程中的压实，裂纹形状受到表面官能团的强烈影响。
