Zhang Lijuan, Zhang Xuehua, Fan Chunhai, Zhang Yi, Hu Jun
Shanghai Institute of Applied Physics, Chinese Academy of Sciences, Shanghai 201800, China.
Langmuir. 2009 Aug 18;25(16):8860-4. doi: 10.1021/la901620e.
The nanoscale gas state at the interfaces of liquids (water, acid, and salt solutions) and highly oriented pyrolytic graphite (HOPG) was investigated via tapping-mode atomic force microscopy (AFM). For the first time, we report that the interfacial gases could form bilayers and trilayers, i.e., on the top of a flat gas layer, there are one or two more gas layers. The formation of these gas layers could be induced by a local supersaturation of gases, which can be achieved by (1) temperature difference between the liquids and the HOPG substrates or (2) exchange ethanol with water. Furthermore, we found that the gas layers were less stable than spherical bubbles. They could transform to bubbles with time or under the perturbation of the AFM tip.
通过轻敲模式原子力显微镜（AFM）研究了液体（水、酸和盐溶液）与高度取向热解石墨（HOPG）界面处的纳米级气态。首次报道界面气体可形成双层和三层结构，即在平坦气体层之上还有一层或两层气体层。这些气体层的形成可由气体的局部过饱和诱导，这可通过以下方式实现：（1）液体与HOPG基底之间的温差，或（2）用乙醇替换水。此外，我们发现这些气体层比球形气泡稳定性差。随着时间推移或在AFM针尖的扰动下，它们会转变为气泡。
