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The thermophoretic motion of a charged spherical colloidal particle and its accompanying cloud of
counterions and co-ions in a temperature gradient is studied theoretically. Using the Debye-H�uckel
approximation, the Soret drift velocity of weakly charged colloids is calculated analytically. For
highly charged colloids, the nonlinear system of electrokinetic equations is solved numerically, and
the effects of high surface potential, dielectrophoresis, and convection are examined. Our results are
in good agreement with some of the recent experiments on highly charged colloids without using
adjustable parameters.
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