Materials Innovation Institute (M2i) , 2628 CD Delft, The Netherlands.
Langmuir. 2013 Sep 10;29(36):11337-43. doi: 10.1021/la402503f. Epub 2013 Aug 27.
By letting a NaCl aqueous solution of low (0.01 M) concentration evaporate on a highly oriented pyrolytic graphite (HOPG) surface, it is possible to form a thin film of salt. However, pre-existing surface nanobubbles prevent the homogeneous coverage of the surface with the salt, keeping the footprint areas on the substrate pristine. Comparing the surface nanobubbles in the salt solution with their associated footprint after drying, provides information on the shrinkage of nanobubbles during the hours-long process of drying the liquid film. At a slightly higher NaCl concentration and thus salt layer thickness, the nanobubbles are covered with a thin blanket of salt. Once the liquid film has evaporated until a water film remains that is smaller than the height of the nanobubbles, the blanket of salt cracks and unfolds into a flower-like pattern of salt flakes that is located at the rim of the nanobubble footprint. The formation of a blanket of salt covering the nanobubbles is likely to considerably or even completely block the gas out-flux from the nanobubble, partially stabilizing the nanobubbles against dissolution.
通过让低浓度（0.01 M）的氯化钠水溶液在高取向热解石墨（HOPG）表面蒸发，可以形成一层薄盐膜。然而，预先存在的表面纳米气泡阻止了盐的均匀覆盖，使基底上的足迹区域保持原始状态。将盐溶液中的表面纳米气泡与其干燥后的相关足迹进行比较，可以提供有关纳米气泡在数小时长的液体膜干燥过程中收缩的信息。在稍高的 NaCl 浓度和因此盐层厚度下，纳米气泡被一层薄薄的盐覆盖。一旦液体膜蒸发至只剩下小于纳米气泡高度的水膜，盐层的毯子就会破裂并展开成位于纳米气泡足迹边缘的花状盐片图案。形成覆盖纳米气泡的盐毯很可能会大大甚至完全阻止气体从纳米气泡中逸出，从而部分稳定纳米气泡防止其溶解。
