Zhang Xue Hua, Zhang Xiaodong, Sun Jielin, Zhang Zhixiang, Li Gang, Fang Haiping, Xiao Xudong, Zeng Xiaocheng, Hu Jun
Nanobiology Laboratory, Bio-X Life Science Research Center, College of Life Science and Biotechnology, Shanghai Jiaotong University, Shanghai 200030, China.
Langmuir. 2007 Feb 13;23(4):1778-83. doi: 10.1021/la062278w. Epub 2006 Dec 14.
We report a novel form of the gaseous state at the interface of water and highly oriented pyrolytic graphite (HOPG) that is induced by local supersaturation of gas. Such local supersaturation of gas next to the HOPG substrate can be achieved by (1) displacing an organic liquid with a gentle flow of water, (2) displacing cold water (approximately 0 degrees C) with a gentle flow of warm water (approximately 40 degrees C), or (3) preheating the HOPG substrate to approximately 80 degrees C before exposing it to water at room temperature. In addition to the spherical-cap-shaped nanobubbles reported by many researchers, flat (quasi-two-dimensional, pancake-like) gas layers and nanobubble-flat gas layer composites (spherical-cap-shaped nanobubbles sitting on top of the quasi-two-dimensional gas layers) were detected. These entities disappeared after the system was subjected to a moderate level of degassing (approximately 0.1 atm for 1.5 h), and they did not form when the liquids involved in the aforementioned displacing procedure (to induce local supersaturation of gas) had been predegassed (to approximately 0.1 atm). The stability and some physical properties of these newly found gaseous states are examined.
我们报道了一种由气体局部过饱和诱导产生的、存在于水与高度取向热解石墨（HOPG）界面处的新型气态形式。紧邻HOPG基底的这种气体局部过饱和可通过以下方式实现：（1）用平缓水流置换有机液体；（2）用平缓的温水流（约40℃）置换冷水（约0℃）；或（3）在将HOPG基底暴露于室温的水之前，先将其预热至约80℃。除了许多研究人员报道的球形帽状纳米气泡外，还检测到了扁平（准二维、薄饼状）气体层以及纳米气泡 - 扁平气体层复合材料（球形帽状纳米气泡位于准二维气体层之上）。在系统进行适度脱气（约0.1个大气压，持续1.5小时）后，这些实体消失了，并且当上述置换过程（以诱导气体局部过饱和）中涉及的液体预先脱气至约0.1个大气压时，它们不会形成。我们对这些新发现的气态形式的稳定性和一些物理性质进行了研究。
