Large Hydrophobic Functional Surface Made By Compounding On The Basis Of DMD

In recent years,hydrophobic surfaces have attracted much attention in engineering applications due to their excellent hydrophobic,anti-corrosion properties,droplet pumping,and controlled oil-water separation.The processing of large areas of high-precision hydropho-bic surfaces often relies on expensive high-precision motion stages or alignment assistance systems for splicing.However,these methods are limited by the accuracy of the platform movement and the machining range and also place high demands on the equipment.It is therefore essential to propose a machining solution that can achieve high precision and large hydrophobic structures.To this end,we propose the use of a 2D planar alignment using a combination of positioning marker substrates and image processing techniques to achieve multiple splices and achieve high precision machining of centimeter-sized hydrophobic structures.At the same time,both natural selection and experimental studies have confirmed that single-scale microstructures are not perfect hydrophobic structures and that hierarchical micro and nanostructures are the optimal design.In order to achieve optimal hierarchical micro and nanostructures,fabrication methods such as photolithography,etching,and nanoimprinting have been proposed in recent years.However,these methods have disadvantages such as complex operation,time-consuming processing,unsuitable for large-scale fabrication,and high requirements for device resolution.In this work,two novel composite processing methods are proposed based on the characteristics of the different nanoscale structures in the micro-nano dual-level structure: 1.the preparation of large-area micro-nano dual-level hydrophobic surfaces based on transfer nano-templates;2.composite processing based on three-dimensional nanostructures to produce large-area micro-nano dual-level hydrophobic surfaces,both of which can be processed with high precision and efficiency without the demand for high-precision moving platforms.The details of the research are as follows:(1)This paper presents a method for the preparation of large-area hydrophobic structures based on digital micromirror device(DMD)maskless lithography.The method combines traditional DMD maskless lithography with image processing technology to achieve efficient preparation of large-area hydrophobic structures with high stitching accuracy.The stitching accuracy of 0.1750 μm and 0.005 μm can be achieved in the x-and y-direction periodically in the DMD maskless lithography system,respectively and the position-specific processing errors are within 1.365 μm and 1.306 μm.To further illustrate the applicability of the image-based stitching method in different devices,we applied it to a femtosecond laser direct writing platform to produce large-area submicron precision hydrophobic structures.(2)Based on the research mentioned above,a composite processing method to prepare large-area micro and nano dual-level hydrophobic structures was proposed.For the nano-layered transferable dual-level structures,we fabricate the top structure of the processing cavity by transferring the nano-template,the cavity support structure by using a DMD maskless lithography system,and the micron-level structure within the cavity.A substrate with positioning marks is used as the cavity substrate to achieve two-dimensional planar alignment for stitching within a centimeter range.As a result of these processes,large-area micro and nano dual-level regular hydrophobic surfaces,custom interval and custom model hydrophobic surfaces,and functional surfaces for water conductivity are rapidly produced.In addition,the processing of micro and nano dual-level structures using the transfer method is extremely efficient.For example,a regular array of structures measuring 720 μm ×720 μm can be processed in just 4 s,compared to 200 min using a femtosecond laser direct writing system,a time difference of three orders of magnitude.For the condition that nano-layers can’t be transferred,a composite processing approach for the preparation of large-area micro-and nano-dual-level hydrophobic structures was proposed.The method utilizes femtosecond laser direct writing techniques with nanoscale resolution and high processing freedom for the preparation of nanolayers in micro-and nano-bipartite structures;The micron-scale rapid processing using DMD maskless lithography with higher preparation efficiency is used to prepare micron structures in micro-nano dual-level structures.The large-area biomimetic locust-leaf structures successfu-lly processed by this method have contact angles of up to 159° and are processed in 1/6th the time of processing using a femtosecond laser.The method is able to achieve high resolution while increasing processing efficiency,providing a feasible solution for the preparation of high-precision dual-level hydrophobic surfaces over large areas.