Study On Silica Based Superhydrophobic Coating

Superhydrophobic surface has many excellent feature,such as self-cleaning,anti-corrosion,anti-icing,etc.These properties have important application prospects in industrial fields and our daily lives,and the prerequisite to achieve superhydrophobility was that the surfaces with low surface free energy and a certain roughness.Perfluorinated chemicals have generally very low surface energies.Silica particles are known to be used for building structured surface.Thus perfluorinated silica particles could be used to build dual-size structured surface with a very low surface energy.In this paper,two methods for preparation of the silica particles were investigated.The first method is the classical Stober sol-gel methods,which could make the SiO2 of nano diameter.The experimental results show that ammonia as a catalyst to speed up the hydrolysis of TEOS,which can affect the size of silica particles.The second method is ultrasonic method,which could make T365 and Z1085 silica water suspension respectively by using mechanical force of ultrasonic homogenizer.The prepared silica particles have been characterized by Scanning Electron Microscopy(SEM)、Atomic Force Microscope(AFM)and Dynamic Light Scattering(DLS).Secondly,the silica particles were modified with perfluoropolyether(PFPE).The reaction mechanism,modification method and the content of modified silica were studied.It was also pointed out that superhydrophobicity depended on both low surface energy and roughness.Finally,the modified silica particles were prepared into the composite coating,and water contact angle of transparent superhydrophobic coating is greater than 1500° and rolling angle less than 10°.A series of performance tests were carried out on the prepared Superhydrophobic and oleophobic coating.