New Interferometric Technique To Evaluate the Electric Charge of Gas Bubbles in Liquids

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• 作者：Mario Corti ; Marco Bonomo ; Antonio Raudino
• 刊名：Langmuir
• 出版年：2012
• 出版时间：April 10, 2012
• 年：2012
• 卷：28
• 期：14
• 页码：6060-6066
• 全文大小：290K
• 年卷期：v.28,no.14(April 10, 2012)
• ISSN：1520-5827

文摘

We report a new interferometric technique to measure the electric charge at the gas鈥搇iquid interface of a bubble in a liquid. The bubble rests by buoyancy against an electrode, and an alternating electric field excites its capillary oscillations. The oscillation amplitude of the quadrupolar mode frequency is measured by the interferometer, and it is used to evaluate the electric charge. The mode frequency scales with the square root of the interfacial tension and with a 鈥?sup>3/₂ power law as a function of the bubble radius. For bubbles in the millimeter diameter range in pure water, the measured negative charge scales with the square of the radius, hence, giving a constant surface charge density on the order of 1.8 脳 10^鈥? C m^鈥?, which is rather consistent with the electrophoretic values reported in the literature.