Undergrad Research Project - particle manipulation via acoustic trapping.

Spring 2018

Hengji Huang
Maysam Chamanzar
Project description

In this project, we aim to manipulate particle concentration/size and position via acoustic trapping. Acoustic trapping works by generating sound waves which will cause density fluctuations in the water, which in turn leads to pressure differences which "push" particles into certain locations in the medium.

Currently, we are using a tube transducer to generate ultrasonic waves that form a Bessel function. The particles will get trapped in either the node or the anti-node of the Bessel function depending on the physical properties of the particles and the medium. Since the strength of Bessel function rings is directly dependent on it's distance to the function center as well as the voltage applied to the transducer, one can adjust the applied voltage such that only the center ring will have enough strength to trap particles. Then by moving the transducer, we can control the position of the Bessel function and consequently the position of the trapped particle. Any free particle that came across the Bessel function center will also be trapped in the center, and depending on whether the particle is solid or liquid, will merge together to create a bigger particle, or lead to an increase in particle concentration at the center.

This technology has many different applications. For example, it can be used in 3d printing. Photosensitive polymer droplets can be suspended in a medium, and acoustic trapping can be used to control particle size, and move it to a desired location for it to be cured. The technology also potentially has important applications in drug delivery. It can be used to concentrate dispersed drug particles in the body, and move it to the location that needs treatment, thus maximizing drug efficiency and minimizing the side effects said drug can have on the human body.

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