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Phys. Rev. Lett. 100, 218301 (2008) [4 pages]

Detection of Elementary Charges on Colloidal Particles

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Filip Strubbe, Filip Beunis, and Kristiaan Neyts
Ghent University, Electronics and Information Systems, Sint-Pietersnieuwstraat 41, Ghent B-9000, Belgium

Received 29 January 2008; published 29 May 2008

We have succeeded in determining the charge of individual colloidal particles with resolution higher than the elementary charge. The number of elementary charges on a particle is obtained from the analysis of optical tracking data of weakly charged silica spheres in an electric field in a nonpolar medium. The analysis also yields an accurate value of the particle size. Measurement of the charge as a function of time reveals events in which the particle loses or gains an elementary charge due to ionization or recombination processes at the surface.

© 2008 The American Physical Society

URL:
http://link.aps.org/doi/10.1103/PhysRevLett.100.218301
DOI:
10.1103/PhysRevLett.100.218301
PACS:
82.70.Dd