Abstract:Although manipulation and control of droplets by applying a moderate voltage has been successfully implemented by many investigators,there are hardly any accurate mathematical equations to describe the relationship between droplet’s contact angle and external voltage during contact angle saturation stage.For this reason,Young Lippmann equation was improved based on energy minimum principle in this paper.A digital microfluidics chip with jagged driving electrode unites was designed by employing theoretical calculation and numerical simulation,and the chip with two dielectric lagers of SiO2 and SiO2 Si3N4 SiO2 respecti vely was fabricated.The experimental results showed that the improved Young Lippmann equation could describe preferably the trends of droplet’s contact angle at the stage of contact angle saturation.Besides,the required voltages in SiO2 Si3N4 SiO2 composite dielectric layer were less than that in SiO2 dielectric layer.