Fabrication Of Biomimetic Superhydrophobic Surfaces By Femtosecond Pulsed Laser And Study Of Their Wettability

The body parts of many plants and animals in nature exhibit unique features such as self-cleaning and waterproofing due to their superhydrophobic surfaces.Inspired by this,people have successfully applied superhydrophobic surfaces in many fields such as life and industry.There are numerous methods to prepare superhydrophobic surfaces,such as templating,chemical deposition and photolithography,but researchers are still actively exploring how to prepare superhydrophobic surfaces in a simpler and more efficient way.In recent years,femtosecond pulsed laser processing has become a more convenient and faster method to produce superhydrophobic surfaces due to its unique advantage of "cold processing".As the preparation of biomimetic superhydrophobic surfaces by femtosecond pulsed lasers is still in the exploratory stage,this paper sets out to investigate the effect of laser processing parameters on the preparation of biomimetic superhydrophobic surfaces,with the following main elements:(1)A femtosecond pulsed laser processing system was set up,and common metallic materials(copper,magnesium alloy and aluminium alloy)were selected as experimental samples.The femtosecond pulsed laser processed the samples placed in air,and the morphological changes on the surface of the laser processed samples were observed in real time by a CCD camera to initially determine the appropriate processing parameters.(2)The surface energy of the sample after laser processing was reduced using fluorosilane and the hydrophobicity of the sample surface was characterised using contact angle measurements.The results showed that the hydrophobicity of the sample surface was better when the laser pulse energy was increased,the scan speed was reduced and the scan spacing was reduced under the action of a linearly polarised laser.(3)The micro-nanostructures on the sample surface were observed by SEM and it was found that when the laser was in the linear polarisation state,increasing the laser pulse energy,slowing down the scanning speed and reducing the scanning spacing,the depth of the grooves ablated by the laser on the sample surface increased,producing richer and tighter micro-nanostructures and increasing the surface roughness.The static water droplets on the sample surface at this time are more difficult to soak into the bottom of the grooves and show better hydrophobicity.(4)The effect of linearly and angularly polarised laser light on the surface depth of the material was investigated and it was found that the angularly polarised laser processed metal surface grooves with a higher depth to width ratio and the droplets tended to be in the Cassie state at the surface.