A microreactor chip integrated with focus ultrasonic transducers prepared by a modified Chemical Foaming Process

In this paper, a microreactor chip integrated with focus ultrasonic transducers prepared by a modified Chemical Foaming Process(CFP) is presented. The device operates by trapping air bubbles within micro pits located in the center of silicon cavities. Focused acoustic waves induced by the spherical shell resonance excite the trapped air bubbles vibrate, resulting in acoustic streaming, which disrupts the laminar flows and increases mass transfer rates and thus accelerate multiphase reactions. First, we shed some light on how oscillating bubbles work in our device. Second, the fabrication of micro glass ultrasonic wave fluidic devices prepared by the modified CFP was introduced. Finally, the resonance properties of the microfluidic device actuated by piezoelectric ceramic are measured experimentally by the Laser Doppler Vibrometer. The results of vibration test show that the resonant frequency of the micro glass bubbles, whether full of fluid or not, is in the range of ultrasonic wave band.