Investigation on the Thermophoresis-Coupled Inertial Sorting of Submicrometer Particles in a Microchannel

The microdevice designed in the present work can sort and separate submicrometer particles in the size range of 0.1-1 mu m by introducing the thermophoretic effect. Simulations were conducted in which particles were considered to be a discrete phase and their trajectories were tracked with the Lagrangian approach. The numerical results showed that 0.1-, 0.5-, and 1.0 mu m-diameter particles could be separated from each other at positions of 30, 63, and 82 mu m above the center of the channel, respectively, when a 10 K temperature difference between the bottom and upper walls was imposed. The focusing positions shift to -30, 36, and 62 mu m above the center of the channel when a 2 K temperature difference imposed. These results were in good agreement with those of the force analysis and experiments. The importance of the thermophoretic effect for submicroparticle sorting is therefore demonstrated by the numerical simulations and experiments.