Droplet Manipulation Method And Mechanism Research On Superwetting Surface

Droplet manipulation technology has broad application prospects in many fields such as biochemistry,droplet transport,droplet collection,and droplet microfluidics.Droplet manipulation on superwetted surfaces has the advantages of no additional energy,spontaneity,volumetric non-loss,and simple manipulation.However,there are problems such as poor control accuracy and stability,so it’s still necessary to systematically study the controllable operation mechanism and behavioral change of droplets.Therefore,in this thesis,an in-depth analysis of the methods and mechanisms for the preparation of superwetted surfaces,droplet directional bounce,controllable droplet splitting,and nondestructive droplet transport was conducted,the research results enrich the droplet manipulation technology on superwetted surfaces and have theoretical and practical value.The main research contents and results of this thesis are as follows:(1)Preparation method and mechanism of super-wetting surface.In order to deeply study the droplet manipulation mechanism and droplet motion law on the existing superwetted surfaces,three wettability models based on superwetted surfaces were established and the influencing factors of surface wettability were explored,the basic principles of preparation of super-wetted surfaces were studied and the mechanism of droplet manipulation was explored based on super-wetted surfaces,and the droplet movement law on the existing superwetting surface was revealed.(2)Method and mechanism of droplet directional bounce.In order to solve the problem that the motion mechanism and motion shape of the existing droplet collision process are still unclear,a method that can control the droplet bouncing and landing point was proposed by utilizing the characteristics that the difference in surface wettability can drive the droplet lateral bouncing.The controllable bouncing mechanism and influence law of droplets on differentially wettability surfaces were studied,and numerical simulations were carried out to analyze the behavior of droplet directional bouncing on differentially wettability surfaces.It was found that adjusting the relative position of the droplets hitting the differentially wettable surfaces enables take control of the droplet bouncing direction and landing point precisely.(3)Method and mechanism of droplet controllable splitting.In order to solve the problems of complicated operation and high cost of splitting devices in existing droplet splitting methods,a new method for controllable splitting of droplets using superhydrophobic pyramid structure was proposed,and a superhydrophobic pyramid structure to achieve controllable splitting of droplets was designed.The splitting mechanism and influence law of droplets on the superhydrophobic pyramid structure were studied,and the behavioral state of the droplet directional splitting model on the superhydrophobic pyramid was numerically simulated and analyzed.It was found that the number of edges on the pyramid can control the number of droplet splitting,which provides a new idea for the development of a simple and cost-effective droplet controllable splitting device.(4)Method and mechanism of droplets non-destructive transport.In order to solve the problem of excessive volume consumption of existing droplets when they are transported on the wedge-shaped area pattern,a novel superwetting pattern that can achieve non-destructive transport of droplets was designed by utilizing the structural features of periodic arrays and low-loss hydrophilic line patterns.The transport mechanism and influence law of droplets on slub-shaped patterns were studied,and the behavioral state of the non-destructive transport model of droplets on slub-shaped patterns was numerically simulated and analyzed.It was found that optimizing the structural parameters of the slub pattern can realize the non-destructive continuous transport of droplets over long distances.