| In order to better adapt to the surrounding environment,organisms have created biological surfaces with exquisite structures and complex components,from which people obtain inspiration and conduct in-depth research on their surfaces.The research process found that biological surfaces with special wettability not only have hydrophobic or superhydrophobic properties,but also have functional characteristics such as droplet manipulation,self-cleaning,anti icing,antibacterial,and oil water separation.Therefore,developing bionic surfaces with different functionalities based on different production needs has important research value and significance.At present,traditional methods for preparing bionic surfaces with superhydrophobic functions generally have shortcomings such as complex preparation processes,high costs,low preparation efficiency,and unstable performance,which seriously restrict the application of superhydrophobic surfaces in production and life.Therefore,this research is based on a new type of laser direct writing lithography system with a series of functions such as automatic focusing and alignment,stepper exposure,grayscale exposure,drag exposure,etc.The design and preparation of biomimetic micro/nano structures with high accuracy,high efficiency,and high stability characteristics will be better applied in biomimetic manufacturing fields such as large depth,multi-layer structure,and large area fabrication.Based on a novel laser direct writing technology and a thick adhesive coating process,using typical lotus leaf and shark skin superhydrophobic surfaces as templates,this paper designs and prepares biomimetic structures using grayscale lithography and drag lithography,and obtains biomimetic lotus leaf microstructures with nanoscale smooth surfaces and biomimetic shark skin microstructures with large aspect ratios.After the wettability test,the bionic lotus leaf surface and the bionic shark skin surface have contact angles of 144° and 153°,respectively,and have excellent hydrophobic and morphological characteristics.Inspired by the super hydrophobic surface of the mushroom shaped microstructure on the paw of a gecko,a micro column array with a mushroom shaped double layer structure was fabricated using a laser direct write alignment lithography process combined with a spin coating method of double layer photoresist.The effects of exposure,development,and glue thickness on the structure morphology were further studied.By changing the duty cycle of the biomimetic microstructure array,the trend of its hydrophobic characteristics was analyzed,and the highest contact angle was measured to be 157°.Using the differences in adhesion of mushroom shaped bionic surfaces to water droplets in different cycles,experiments on droplet manipulation were conducted,further verifying the potential application of bionic superhydrophobic surfaces in the direction of droplet transportation and droplet fusion.Based on previous research,a hydrophobic coating was further prepared using nano SiO2 particles,and a superhydrophobic bionic microstructure coating was prepared by combining the bionic structure with the hydrophobic coating.The contact angle was measured to be 154°,with excellent superhydrophobic properties.After soaking in pH=1 and pH=13 acid and alkali solutions for different times,the contact angle remains around 150°,with excellent chemical stability.In addition,the bionic microstructure coating exhibits excellent self-cleaning effects in different pollutant tests.Finally,this study combined nanoimprinting technology to prepare the surface of superhydrophobic bionic microstructure coating with large format and high efficiency,providing a reliable way for its future industrial production. |
