Driver System Design Of Digital Microfluidic Chip

In recent years,digital microfluidic chips have been widely used in biochemical analysis,high-tech medical treatment,optical research and other fields by virtue of their advantages of miniaturization,automation,high efficiency and low cost.In this paper,the driving principle of digital microfluidic chip is deeply studied,and the driving system and supporting Android software program are designed.Based on the physical field coupling model simulation analysis,the electrode layer,dielectric layer and hydrophobic layer of the digital microfluidic chip were prepared,and the test platform was established based on the prepared microfluidic chip to test and verify the drive system.Firstly,the driving principle based on dielectric wetting effect is analyzed theoretically.The wetting phenomenon and the principle and method of droplet drive based on surface tension were studied.The theoretical significance and non-ideal factors of lippmann-young theorem are analyzed.The saturation of contact Angle and lag effect of contact Angle are studied.Secondly,a micro-droplet drive system is designed for human-computer interaction through touch screen.The photoelectric coupling circuit and the reusable switch electrode array are designed and realized.An android-based electrode control program is developed from the application framework layer,the system runtime layer and the hardware abstraction layer.Through the control of virtual keys in the touch screen,the true electrode on and off state is controlled,and the stable continuously adjustable dc driving voltage and ac driving voltage with adjustable frequency can be output.Then,the droplet is analyzed by using Comsol multi-physical field simulation software and two-phase flow moving grid interface tracking method.The flow velocity and surface pressure of microfluidic system were simulated,and the electric potential distribution of the system model and the electric field contour distribution near the three-phase contact point were analyzed,and the static simulation analysis was completed.Different voltages are applied on the two sides of the droplet to form the difference value of the surface tension gradient and complete the dynamic simulation analysis.Finally,the electrode layer,dielectric layer and hydrophobic layer of the digital microfluidic chip were prepared to establish an experimental platform for the test of the drive system.The DC voltage and AC voltage droplet drive experiments were carried out on dielectric layers of different thicknesses and different volume droplets.On the three spin-coated dielectric layers,the driving of 1.2?L droplets at 110 V was realized.Experimental data shows that the dielectric layer breakdown voltage can be increased by using the AC drive voltage and increasing the dielectric layer thickness,and the dielectric wetting phenomenon of the smaller volume droplets is more pronounced.The test results show that the drive system can control the on-off of the electrode,and can output the continuously adjustable DC drive voltage and the AC drive voltage with adjustable amplitude and frequency.