Research On Novel Piezoelectric Microfluidic Actuators

Microfluidic system has a broad application prospect in many fields such as chemistry,biology and medicine.Microfluidic driving technology is very important to the development of microfluidic technology.Existing positive piezoelectric displacement pumps have problems of flow pulsation and even backflow when the output flow is in a level of?L/min.Sizes of existing dynamic piezoelectric pumps are too large for microfluidic applications.The cost of a micro pump integrated on a microfluidic chip is too high,while using a separated micro pump the problem of cross-contamination.Based on the ultrasonic vibration excited by piezoelectric transducers,this paper studys two novel piezoelectric microfluidics actuators with the separate design of piezoelectric transducers and pump chambers,and explores the new structure and new principle of microfluidics actuators based on piezoelectric transducers.A novel piezoelectric ultrasonic bubble microfluidic actuator is studyed.A piezoelectric wafer transducer is employed to excite ultrasound in a chamber of a microfluidic chip,to generate bubbles in the liquid and drive the microfluidics.Experiment results show that the resonant frequency of the piezoelectric wafer transducer is around 23.05 k Hz,the minimum stable flow rate under the voltage of 80V_pp is 0.1873n L/min,and the maximum flow rate under the voltage of 130V_pp is 17.741n L/min.A novel piezoelectric acoustic microfluidic actuator is studyed.Ultrasound is excited in the tank of a microfluidic chip by a Langevin transducer with an acoustic horn,and the microfluidics is driven by acoustic flow.Experiment results show that the resonant frequency of the Langevin transducer is around 32.3k Hz,the mechanical quality factor is 1928 without load,the minimum stable flow rate is 2.71?L/min at low voltage,the maximum flow rate is 76.03?L/min at 70V_ppvoltage,and the maximum output pressure is greater than 0.462k Pa.The experimental results show that,the piezoelectric ultrasonic bubble microfluidic actuator can generate micro flow with a level of n L/min,with a certain prospect in applications requiring tiny flow rate.The piezoelectric acoustic microfluidic actuator can generate micro flow with a level of?L/min,with a fast start-stop response,avoiding the cross-contamination problem,which is expected to be applied in microfluidic droplet generation,in vitro detection and other fields.