Binary particle acoustophoresis separation based on nodal position adjustment through PDMS wall

This paper presents binary particle separation using acoustophoresis where nodal position can be readily adjustable by integrating PDMS wall in the microfluidic channel. Here, a new fabrication of PDMS wall is introduced where a silicon mold for PDMS wall and a main channel were simultaneously fabricated on a Si wafer substrate so that a precisely controllable PDMS wall fabrication can be achieved. The PDMS wall with acoustic transparency is integrated in the main channel, which allows decoupling of the acoustic boundary from the fluidic boundary. Since it results in generation of nodal and anti-nodal positions, each for only single one in the fluidic main channel, polystyrene(PS) and PDMS particles are focused on at nodal and anti-nodal position, respectively, followed by separation into each outlet.