Study On The Control Mechanism Of Non-wetting Interface And Its Application In Functional Material Design

Non-wetting interfaces are widely used and plays an important role in daily life and industrial production,including self-cleaning anti-fouling,deicing anti-frost and anti-bacterial adhesion and other fields.In recent years,due to the rapid development of fluid mechanics and photothermal science and the cross-integration of disciplines,non-wetting surfaces with special micro and nano structures have begun to show unique value in some new functional materials fields,such as polymer microspheres,photonic crystal pigments and thermal management metamaterials.However,the complexity of the mechanism of solid-liquid interface and the complexity of photothermal regulation greatly limit its further development.The limitations of relevant theoretical mechanisms,such as the instability of highly viscous fluids on solid surfaces,the rapid evaporation of micro-nano suspended droplets,and the performance balance between optical scattering and low surface adhesion,are urgent problems to be explored and solved.On this basis,based on the non-infiltrating theoretical system,this Dissertation systematically studies the cross-scale interaction of the solid-liquid interface and the synergistic effect between the interface and external fields such as light,electricity and fluid,so as to realize the precise construction of the functional interface material structure and the precise regulation of its properties,and successively develops a new platform for micromaterial synthesis and a durable thermal management material.It provides a new possibility for the functional application of non-wetting materials.The research in this dissertation has not only made remarkable progress in the theoretical mechanism,but also greatly expanded the application scenarios of non-wetting surface interface in practical application,successfully solved challenges in this field,and laid a foundation for its further development.1.The superamphiphobic material based on the nanoparticle assembly of the fractal structure has very low surface energy and solid-liquid adhesion,which can spontaneously drive the highly viscous fluid fragmentation（i.e.the classic Plateau-Rayleigh instability）to form spherical microdroplets,thus having the potential to produce polymeric microspheres.Although the"In Fiber"manufacturing technology based on the Rayleigh instability phenomenon can also be used to achieve the fabrication of microspheres with adjustable size,scalability,and versatility,it is competitive with traditional microsphere preparation methods such as emulsion polymerization and microfluidic method.However,because the instability of the fluid within the fiber cladding must be induced by thermal annealing,and the resulting microspheres can only be collected after the fiber cladding is dissolved,obtaining non-polluting microspheres remains challenging for materials that are not resistant to high temperatures or that degrade easily.Based on the physical mechanism and hydrodynamic analysis of the Plateau-Rayleigh instability of the highly viscous fluid,this dissertation utilizes the ultra-low surface energy of the superamphiphobic surface and multidimensional solid-liquid interface regulation to maximize the surface tension of the liquid column,thus successfully driving the high-viscosity polymeric liquid column to break up and form spherical droplets at room temperature.An ultra-fast,spontaneous technique for fabricating polymeric microspheres based on Plateau-Rayleigh instability has been developed.The technology does not rely on any additional emulsifiers or processing fluids and requires no post-treatment steps,effectively eliminating the limitations of high temperature heating and cladding contamination in traditional"In Fiber"strategies.This simple strategy allows us to obtain functional,structural,multi-shape polymeric microspheres with narrow size distributions in large quantities from a variety of materials.2.In this dissertation,a facile strategy for large-scale production of cellulose-based microspheres was proposed based on the silicon-based superamphiphobic surface by regulating droplet evaporation and the driving force of the solid-liquid interface.By modulating the mechanism of solid-liquid interface interaction,we demonstrate a spray-based,scalable fabrication method for colored cellulose microspheres.A series of cellulose microsphere pigments spanning the entire visible spectrum were successfully made without any additional emulsifiers or processing fluids.In addition,our new method reduces the manufacturing time to less than 2 hours,a significant reduction in production time compared to the approximately one week required for traditional emulsification technology,which increases productivity and makes our strategy highly attractive for mass production.3.Non-wetting materials with hierarchical porous structure based on classical nanoparticle assembly have not only the solid-liquid surface properties of anti-pollution adhesion,but also the solid-air interface properties of high optical scattering,so they not only have the self-cleaning performance of anti-contamination,but also can realize the effect of cooling through photothermal conversion,so they have the basis and potential to develop durable radiative cooling metamaterials.Based on the understanding of the mechanism of solid-liquid interaction and photothermal conversion process,this dissertation proposes a structural design strategy with both high solar reflectivity and superhydrophobicity,that is,multi-scale Ti O₂ nanoparticles with anti-photothermal aging properties and fluorosilane with high thermal emissivity in the atmospheric transparency window are used to form a hierarchical porous film through evaporation-driven assembly,thus ensuring balanced anti-pollution performance and excellent optical properties.Based on Cassie-Baxter theory,the coating can simultaneously achieve extremely low surface adhesion and superhydrophobicity,thereby reducing the accumulation of contaminants.In this dissertation,the simulation experiments equivalent to 3 years of natural pollution and 1 year of natural sunlight exposure were carried out in accordance with ASTM standards.The solar reflectance of the tested coating was only reduced by 0.4%and 0.5%respectively compared with that before the test,and the cooling performance was hardly affected.The anti-aging radiative cooling coating is scalable and can be sprayed on the exterior surfaces of desired outdoor buildings or large containers to provide long term sub-ambient cooling.