Performance Analysis of a Microfluidic Pump Based on Combined Actuation of the Piezoelectric Effect and Liquid Crystal Backflow Effect.

A novel combined actuation method based on the piezoelectric effect and liquid crystal backflow effect is proposed in this paper. The coupling mechanism of a piezoelectric transducer (PZT) and liquid crystal (LC) in a combined driving mode is analyzed, and the governing equations of electromechanical coupling based on inverse piezoelectric effect and the classical Leslie-Ericksen backflow equation are modified under combined driving method. The new multifield coupling dynamic equations for numerical analysis is established. Experimentally, a sandwiched micropump was manufactured and sealed with wet etching technology on a glass wafer. A testing platform was built to analyze the particles motion and the flow rates were measured with both single PZT or LC actuation and combined actuation. Comparing the results of the numerical analysis and experimental testing of the flow rate and LC molecule motion under different driving voltages and frequencies, the performance of the PZT/LC combined driving is found to be superior to that of the single driving mode (PZT or LC driving) under the same driving conditions. Moreover, the new combined driving mode overcome the disadvantages of single driving mode and enhance the driving efficiency significantly. The simulation results are in good agreement with the experimental data. The maximum flow rate of the micropump achieved was 4.494 μL/min with combined driving method.