title: Radiation dominated acoustophoresis driven by surface acoustic waves.
abstract: Acoustophoresis-based particle manipulation in microfluidics has gained increasing attention in recent years. Despite the fact that experimental studies have been extensively performed to demonstrate this technique for various microfluidic applications, numerical simulation of acoustophoresis driven by surface acoustic waves (SAWs) has still been largely unexplored. In this work, a numerical model taking into account the acoustic-piezoelectric interaction was developed to simulate the generation of a standing surface acoustic wave (SSAW) field and predict the acoustic pressure field in the liquid. Acoustic radiation dominated particle tracing was performed to simulate acoustophoresis of particles with different sizes undergoing a SSAW field. A microfluidic device composed of two interdigital transducers (IDTs) for SAW generation and a microfluidic channel was fabricated for experimental validation. Numerical simulations could well capture the focusing phenomenon of particles to the pressure nodes in the experimental observation. Further comparison of particle trajectories demonstrated considerably quantitative agreement between numerical simulations and experimental results with fitting in the applied voltage. Particle switching was also demonstrated using the fabricated device that could be further developed as an active particle sorting device.
authors.affiliation: Pillar of Engineering Product Development, Singapore University of Technology and Design, Singapore 487372, Singapore. Electronic address: jinhong_guo@sutd.edu.sg.
authors.forename: Jinhong
authors.initials: J
authors.lastname: Guo
authors.affiliation: School of Chemical and Biomedical Engineering, Nanyang Technological University, Singapore 637459, Singapore.
authors.forename: Yuejun
authors.initials: Y
authors.lastname: Kang
authors.affiliation: Pillar of Engineering Product Development, Singapore University of Technology and Design, Singapore 487372, Singapore. Electronic address: aiye@sutd.edu.sg.
authors.forename: Ye
authors.initials: Y
authors.lastname: Ai
keywords: Acoustic radiation; Acoustophoresis; Numerical simulation; Particle switching; Surface acoustic wave (SAW)