Nano‐Scale Particle Separation with Tilted Standing Surface Acoustic Wave: Experimental and Numerical Approaches

Abstract

To eliminate the precise microchannel alignment requirement for parallel surface acoustic wave (pSSAW) fabrication, a tilted standing surface acoustic wave (tSSAW) is incorporated in many studies recently. In tSSAW, the microchannel is tilted at a specific angle (θ) instead of being parallel to interdigital transducer fingers. This causes the pressure node lines to be formed in the tilted direction to the fluid flow, which leads to better controllability in the separation or manipulation of the particles and higher efficiency. In this study, we developed a three‐dimensional (3D) finite element analysis (FEA) simulation to study the effect of the tSSAW device parameters to maximize its performance in particle separation. The outcomes of the 3D simulation of tSSAW devices indicate that the optimum values of the microchannel tilt angle (θ) and the aperture length must be between 5° ≤ θ ≤ 15° and the same as the microchannel length, respectively. The optimum values are considered in the fabrication of the tSSAW device, where it is tested with 20 μm, 15 μm, and 600 nm polystyrene particles.