Nanoparticle separation by laser induced thermophoresis in nanochannel

Thermophoresis is a micro- and nanoparticle transport phenomenon along a temperature gradient in fluids. In the present study, we apply the microscale thermophoresis to the nanoparticle flow control at a Y-shaped bifurcation in a microchannel. The flow in the parent channel is separated at the bifurcation so that the flows downstream in two branched channels with a same flow rate are realized. One of the branched channel has a thin-film electric heater at the entrance to induce the local temperature rise. Since the nanoparticles are repelled from the hot region by the thermophoresis, they hardly enter into the branched channel with the heater. As a result, only the solvent flow into the branched channel with the heater and the nanoparticles are transported to another branched channel.