By measuring the stable charge on oil drops in air, Millikan demonstrated the discrete nature of electric charge. We extend his approach to the charge on solid-liquid interfaces, and focus on the dynamics of the discrete fluctuations. Our measurements are accurate and fast enough to observe changes of one elementary charge. Experiments over thousands of seconds yield information about the fast dynamics of electrochemical reactions, relevant for physicochemical and biological systems. As an example, we study (dis)charging processes on colloidal particles in a nonpolar liquid.
- Received 26 May 2011
© 2012 American Physical Society
Published 6 January 2012
A new technique measures each unit of charge that accumulates on a submerged plastic bead, unprecedented resolution for a liquid-solid interface and an experiment that may benefit a variety of commercial devices and processes.
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