Preparation And Properties Of Transparent Super Hydrophobic Porous Glass

In recent years,super hydrophobic surfaces have made great progress in theoretical research and preparation technology.The super hydrophobic glass surface can reduce the pollution of dust and oil,improve its beauty and practicality.However,how to ensure that the coating has good mechanical durability without affecting the light transmittance of the glass has always been an urgent problem.The nano structure and pore size of the porous glass can be adjusted by the process parameters,and it has good light transmittance and mechanical strength,it is very suitable for the preparation of super hydrophobic transparent surface.The effect of different phase separation temperature,phase separation time and acid treatment process on the nano structure and properties of glass surface was studied with 68SiO₂-25B₂O₃-7Na₂O as the parent glass.And the wear resistance of the surface was improved by subsequent heat treatment.In addition,the removal situation of different sizes,quantities and types of particles by self-propelled jumping of condensate droplets was also studied.It is found that the phase separation process determines the shape and pore size of the nanostructure.If the phase separation time is too long and the phase separation temperature is too high,it will lead to excessive phase separation,which affect the subsequent acid etching and surface transmittance.If the phase separation time is too short and the phase separation temperature is too low,it will lead to the incomplete phase separation and difficult to form a rough nano structure.The phase separation of 620?for 12 hours at low temperature is a better phase separation process.The granular structure with a diameter of 30 to 60 nm is obtained.The gap between the particles is 10 to20 nm,and the nanoscale nanostructures are obtained at 700?for 2 hours at high temperature.The thickness of the skeleton is 30 to 50 nm,and the size of the mesh is from 100 to 200 nm.The glass obtained by the two optimum phase separation processes can get more than 155 degrees of water droplet contact angle,and the transmittance of the glass is also not changed.Through the study of different acid treatment processes,it is found that the treatment of hydrochloric acid can easily break the surface of the glass and reduce the transmittance seriously.The water contact angle is about 141°after the treatment of 1 mol/L hydrochloric acid at 95?for 24hours.The direct treatment of hydrofluoric acid will produce micron notch,although the water contact angle of the glass surface is more than 150 degrees after 2 to 5 minutes with 2.5%HF,but the loss of light transmittance is obvious.The glass is acid-pretreated,and then treated by mixed acid,it can reach the contact angle of water droplets above 155°,and has good transparence.The average transmittance is 91-92%.After acid treatment,the surface structure is fragile,and subsequent heat treatment is needed to improve its surface wear resistance.The wear resistance of acid treated glass increased significantly after heat-treated at 530?for 6 hours to 12 hours.The eraser serves as a friction surface with a contact area of 1 cm² and a load weight of 200 g.After 50 times of friction,the water droplet contact angle still has more than 145 degrees.The transparent superhydrophobic porous glass surface has excellent anti condensation and water droplet self-bouncing properties.In the process of condensation,two kinds of condensate jumping motions are found by high-speed camera.And two kinds of jumping-motion can take away dust and particles deposited on the surface.At the same time,the smaller and fewer the particles are,the more obvious the effect of condensation jumping removal is.By comparing different dedusting methods,it is found that the mechanical vibration and the wind blowing can only remove the larger dust,while the water droplet rolling and the condensate drop can completely remove the fine dust on the surface.