纳米气泡和纳米液滴:成核与生长动力学

        气泡是液体中充满气体的空穴,在我们的日常生活中随处可见。而纳米气泡,就是指直径在纳米尺度的气泡。根据热力学理论公式的计算结果,由于内部巨大的拉普拉斯压力,表面纳米气泡应该在几个毫秒内就完全溶解,但自2000年AFM第一次检测到表面纳米气泡的存在以来,诸多实验结果表明,表面纳米气泡可以稳定存在长达几天甚至更久。尽管这一矛盾尚未得到解决,但纳米气泡已经在表面清洁,水处理,医疗等众多领域发挥了重要作用。纳米液滴与纳米气泡无论从性质还是研究方法上都有很多类似的地方。目前研究表面纳米气泡及纳米液滴的主要技术包括AFM, 荧光显微镜,SEM, TEM等,而SPRM作为一种对折射率敏感的光学检测技术,由于具有无损、免标记、时间分辨率高、定量检测等优点,在对表面纳米气泡及纳米液滴的研究中也发挥着不可或缺的作用。研究表面纳米气泡及纳米液滴的溶解等动力学过程,不但有利于理解其基本物理化学性质以揭开其长寿命之谜,同时还可以进一步指导其实际应用的发展。

 

       图1. 纳米液滴与疏水界面相互作用的可视化                          图2. 微米/毫米级的气泡是由纳米气泡长大形成的吗?
                  (unpublished results)

 

参考文献:

[1] Muidh Alheshibri, Jing Qian, Marie Jehannin, and Vincent S. J. Craig*, A History of Nanobubbles, Langmuir, 2016, 32, 11086.

[2] Detlef Lohse*, Xuehua Zhang*, Surface Nanobubbles and Nanodroplets, Reviews of Modern Physics, 2015, 87, 981.

 

Soft Matter: Nanobubbles & Nanodroplets

    Nanobubbles are nanoscopic gaseous cavities in solution. Based on thermodynamic calculation, surface nanobubbles should be dissolved in several microseconds because of large Laplace pressure inside. The unexpected long existence of surface nanobubbles has been heatedly debated for a long while since they were first speculated by AFM in 2000. And it has been widely applied in variety fields from surface cleaning, microfluidics, to water treatments, and medical diagnosis. Nanodroplets, which are nanoscopic droplets, show similar properties as surface nanobubbles and can be easily confused with surface nanobubbles. At present, the main technologies to study surface nanobubble and nanodroplets include AFM, fluorescence microscope, SEM, TEM and so on. With the advantages of non-invasive, quantitative detection and good time-resolution, SPRM plays an important role in studying surface nanobubble. The study on the kinetics process of surface nanobubbles and nanodroplets can not only help to further understand their properties, but also guide the development of their applications.

 

References:

[1] Muidh Alheshibri, Jing Qian, Marie Jehannin, and Vincent S. J. Craig*, A History of Nanobubbles, Langmuir, 2016, 32, 11086.

[2] Detlef Lohse*, Xuehua Zhang*, Surface Nanobubbles and Nanodroplets, Reviews of Modern Physics, 2015, 87, 981.

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