Acoustic Tweezing and Patterning of Concentration Fields in Microfluidics

Abstract

We demonstrate theoretically that acoustic forces acting on inhomogeneous fluids can be used to pattern and manipulate solute concentration fields into spatio-temporally controllable configurations stabilized against gravity. A theoretical framework describing the dynamics of concentration fields that weakly perturb the fluid density and speed of sound is presented and applied to study manipulation of concentration fields in rectangular-channel acoustic eigenmodes and in Bessel-function acoustic vortices. In the first example, methods to obtain horizontal and vertical multi-layer stratification of the concentration field at the end of a flow-through channel are presented. In the second example, we demonstrate acoustic tweezing and spatio-temporal manipulation of a local high-concentration region in a lower-concentration medium, thereby extending the realm of acoustic tweezing to include concentration fields.

arXiv commentRevtex, 9 pages, 5 eps figures

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Cited by in corpus (7)

• Acoustic streaming and its suppression in inhomogeneous fluids
• Characterization of Acoustic Streaming in Gradients of Density and Compressibility
• Theory of pressure acoustics with thermoviscous boundary layers and streaming in elastic cavities
• Fast microscale acoustic streaming driven by a temperature-gradient-induced non-dissipative acoustic body force
• Theory of Nonlinear Acoustic Forces Acting on Inhomogeneous Fluids
• On the stability of inhomogeneous fluids under acoustic fields
• Theoretical aspects of microscale acoustofluidics