Acoustic microreactors for chemical engineering

Acoustic microreactors that function with acoustics to drive reactant fluids at the microscale make a comprehensive lab-on-a-chip revolution in chemical engineering. Compared to passive microreactors, acoustics-enabled active microreactors offer many outstanding merits such as flexible control, short mixing distance, and intensive reaction kinetics. Herein, we provide an overview of the state-of-the-art of acoustic microreactors for chemical process intensification and reaction engineering. We firstly discuss the established bulk acoustic wave and surface acoustic wave microreactors and highlight their underlying working principles. Next, we present the achievements of acoustic microreactors for the engineering of chemicals and materials from both confined microchannels and sessile microdrops. Finally, we outline emerging challenges and opportunities facing acoustic microfluidics for inspiring future directions in this area. This review article aims not only to elucidate the state-of-the-art acoustic microfluidics for chemical engineering, but also to inspire more advanced lab-on-a-chip systems for facilitating process intensification applications of both scientific and industrial interest.