Fabrication Of Hydrophobic Dual-scale Microstructured Surfaces Via Laser Processing And Investigation Of Their Anti-adhesive Properties

Micro-nanostructures can change the wettability of a solid surface and affect the anti-liquid-adhesive performance of the surface.However,the anti-adhesive performance of single-scale microstructured surfaces is often inadequate in high-viscous liquid environment.Mimicking the micro-nanostructures on the super-hydrophobic surface of lotus leaf,dual-scale microstructures consisting of crater-shaped microprotrusion arrays(100 ?m scale)and laser etched microstructures(1 ?m scale),were designed and fabricated on steel surfaces via one-step laser processing.Aiming at problems of resin adhesion on carbon fiber prepreg cutting tool surfaces and blood adhesion on surgical scalpel surfaces,the wetting and anti-adhesive performance of the hydrophobic dual-scale microstructured surfaces were tested and investigated.Laser etched microstructures with different morphologies were fabricated by changing laser processing parameters.And effect of laser scanning rate,laser power,processing times and laser path spacing on the surface morphologies were investigated.Reasonable laser processing paths and process parameters were designed,and dual-scale microstructures with different protrusion sizes were fabricated.Surface morphologies of the dual-scale microstructures were observed and analyzed by a scanning electron microscopy and a 3D optical profiler.And the effects of protrusion height,spacing and diameter parameters on the surface morphology and roughness of the dual-scale microstructures were studied.Hydrophobic dual-scale microstructured surfaces with excellent anti-liquid-adhesive properties were obtained by suitable post-treatment of the laser-processed dual-scale microstructures.The adhesive situations of water,resin and serum droplets on the hydrophobic dual-scale microstructured surfaces with different protrusion arrays were tested and analyzed.Based on Wenzel and Cassie wetting models,influences of the microstructured surface morphology and roughness on the anti-liquid-adhesive properties were explored,and the structural parameters of the hydrophobic dual-scale microstructured surfaces were optimized.The fabricated anti-resin-adhesive dual-scale microstructured surfaces showed a water contact angle of 157.2° and sliding angle of 2.8°,as well as a resin contact angle of 149.7° and sliding angle of 7.3°.The dual-scale microstructured surfaces could maintain an excellent anti-resin-adhesive property enven when the droplets were extruded.The fabricated anti-serum-adhesive dual-scale microstructured surfaces showed a water contact angle of 137.1° and a serum contact angle of 124.2°,and the serum contact angle were 74.9% and 38.9% larger than those of the smooth and single-scale microstructured surfaces,respectively.The results showed that with the increase of microprotrusion height as well as decrease of microprotrusion spacing and diameter,the surface roughness of dual-scale microstructured surface increased and solid-liquid interface reduced,leading to better hydrophobic and anti-liquid-adhesive properties.