Exceptionally Transparent Superhydrophobic Glass Surfaces Fabricated By Ultrafast Laser And Their Stability And Durability

Superhydrophobic surfaces with excellent self-cleaning property have attracted tremendous scientific and industrial attentions in recent years.It is well known that hierarchical micro-nano structure and low-surface-energy are two main factors resulting in superhydrophobicity.Nowadays,hierarchical micro-nano structure with superhydrophobicity has been demonstrated on a variety of materials such as silicon,metal,metallic oxide,polymer and textile.Among current artificial superhydrophobic surfaces,self-cleaning glass surfaces with high transparency exhibit great application potentials in diverse industrial areas such as windshields for automobiles,wing mirrors,anti-fouling mirrors,windows,microfluidic devices,safety glass and solar panels.However,superhydrophobicity requires high surface roughness which inevitably results in the loss of surface transmittance.How to fabricate durable and robust surface micronano structures to realize self-cleaning transparent superhydrophobic glass surface,is the prominent question.In this thesis,a novel approach named multi-pulse laser ablation with gradual changing energy was first proposed by ultrafast laser direct-writing dispersed micro-pit array to provide higher surface roughness and to guarantee enough unprocessed surface area for high transparency,meanwhile to introduce multiple laser processing within each pit to induce maximized nano-structure roughness.The as-prepared dual micro-nano structure on silica glass surface by multi-pulse laser direct-writing technology was combined with dispersed periodic micropit array,and abundant self-organized nanoripples and nanoparticles appeared inside every micropit.After chemical surface modification,the glass surfaces showed superhydrophobicity with a static contact angle of 161.2 ?0.4? with a 4 ?L water droplet,a sliding angle of 2?1? with a 5 ?L water droplet,and a transparency over 92% in the visible light and near-infrared spectrum.Through a series of tests of stability and durability,these transparent superhydrophobic glass surfaces were confirmed to exhibit persistent water repellency soaking in water for at least 168 h,strong impact resistance of water impinging beyond 9 kg for half-an-hour and thermal stability up to 400?.In this thesis,a directional lapping laser spot processing technology was proposed,which improved the scanning speed to the pulse separation,to fabricate hierarchical micro-nano structure with periodic microarrays,submicron ripples and abundant nanoparticles on silicate glass surfaces,achieving a static contact angle of 152.4° and a transparency over 80% in the visible light spectrum.In this thesis,multi-pulse laser ablation with gradual changing energy was applied on silicate glass surfaces to fabricate distributed micropit arrays with nanoripples and porous structures,achieving a static contact angle of 161° and a transparency over 85% in the visible light spectrum.