The effect of temperature distribution on the mass species transport in micro-channels driven by electroosmosis*

The temperature-dependent Poisson- Boltzmann equation, momentum equation and the mass transport equation in a rectangular micro-channel flow driven by electroosmosis were derived firstly. Then these equations were solved numerically through the finite difference method. The effects of different temperature distributions on the axial velocity profile, the maximum of the species concentration, the symmetry of the species distribution and the width of sample band were analyzed. The results show that the maximum of the species concentration decreases with increasing of time for different uniform temperatures. The existence of lateral, radial and especially axial temperature gradient makes the species diffuse slowly, and narrows the sample band. The best way of making the sample band transport and separate effectively is forcing a temperature gradient along the axial direction.