Preparation method of hydrophobic high-purity silicon dioxide coating

The invention discloses a preparation method of a hydrophobic high-purity silicon dioxide coating, which comprises the following steps: obtaining alkaline silicon dioxide sol with different solid contents through hydrolytic condensation reaction of organosilane and filtration and concentration of a ceramic membrane, and coating the surface of silicon dioxide with a low-surface-energy substance through reaction of an alcoholic solution of a silane derivative and the alkaline silicon sol, thereby obtaining the hydrophobic high-purity silicon dioxide coating. The alcoholic solution of the silane derivative and the photoinitiator are removed through secondary filtration and concentration of a ceramic membrane, subsequent curing is facilitated, and finally the hydrophobic high-purity silicon dioxide coating is prepared through a spin-coating method and an ultraviolet curing technology. The prepared silicon dioxide coating is uniform in particle size, good in sphericity degree, uniform, free of cracks, good in hydr