L. Gorretalini et al., SORTING OF BROWNIAN PARTICLES BY THE PULSED APPLICATION OF AN ASYMMETRIC POTENTIAL, Physical review. E, Statistical physics, plasmas, fluids, and related interdisciplinary topics, 56(2), 1997, pp. 2025-2034
We submit a suspension of Brownian latex spheres in water to a spatial
ly periodic and asymmetric potential successively switched on and off.
Such a potential is created by dielectrophoretically induced forces r
esulting from the application of a high-frequency electric field betwe
en a plane electrode and a blazed optical grating. As expected, we obs
erve a net macroscopic drift of the particles. Their average velocitie
s have been measured as a function of the time during which the field
is switched off. We observe a quantitative agreement with the theoreti
cal predictions. In particular, the velocities strongly differ accordi
ng to the size of the latex spheres, which should open the way to devi
ces aimed at the separation of micrometer and submicrometer particles.
The geometry of the gratings as well as the concentration and the sur
face functions of the particles has also been investigated.