Multiphysics in acoustofluidics for materials science and biochemistry

Acoustofluidic technologies are widely used in biological, chemical, and materials applications because they enable contact- and label-free manipulation with high energy concentration and strong actuation capability. In surface acoustic wave-based systems, acoustic-wave propagation on piezoelectric substrates is accompanied by electric-field generation, acoustic streaming in adjacent fluids, and dissipation-induced thermal effects, giving rise to coupled acoustic, electric, and thermal fields that jointly govern microscale transport and reaction processes. Although existing reviews have mainly emphasized applications, less attention has been paid to these coupled physical effects directly associated with acoustic-wave excitation from a unified multiphysics perspective. Here, we review recent theoretical developments and representative applications of acoustically induced coupled physical fields in materials science and biochemistry. Distinct from conventional application-oriented reviews, this review is organized according to the dominant coupled physical fields and force balances involved, allowing a clearer connection between physical mechanisms and functional performance. We first compare the major acoustofluidic forces governing particle motion and then discuss representative studies involving acoustic streaming–acoustic radiation coupling, acoustic–electric coupling, and acoustothermal effects. The significance of multiphysics coupling for applications in materials science and biochemistry is highlighted, while emerging opportunities for integrating artificial intelligence and machine learning into acoustofluidic design and optimization are also identified. Overall, this review provides clearer guidance for understanding and advancing multiphysics-driven acoustofluidic systems.