Abstract
The purpose is to improve the hardness of hollow silica antireflection (AR) coatings. In this paper, a colloidal solution of hollow silica nanospheres (HSNs) is prepared by sol-gel method, and HNSs@TiO2 colloidal solution is prepared by depositing nano-TiO2 on the surface of HSNs through hydrolysis and condensation of titanium isopropoxide (TTIP). The HSNs@TiO2/ACSS AR solution is prepared by mixed the HSNs@TiO2 colloidal solution and acidic silica sol (ACSS). The morphology of HSNs and HSNs@TiO2 nanoparticles are analyzed by ultra-high resolution field emission scanning electron microscope, high-resolution transmission electron microscope and atomic force microscope. The transmittance, hardness and elastic modulus of HSNs/ACSS AR coating and HSNs@TiO2/ACSS AR coating are analyzed by UV-visible spectrophotometer and nanoindenter respectively. After the nano-TiO2 is deposited on the surface of HSNs, the particle size of the HSNs@TiO2 nanoparticles in antireflection liquid increased by 1~30 nm compared with the particle size of the HSNs; Particles and clusters on the surface of AR coating that prepared by HSNs@TiO2/ACSS AR liquid are obvious, and the surface roughness (RMS) of the AR coating could reach 9.61 nm, which is much higher than 3.62 nm of HSNs/ACSS AR coating; HSNs@TiO2/ACSS AR coating with larger HSNs@TiO2 nanoparticles increased the transmittance of glass at 550 nm by 1.3%, which is lower than 2.8% of HSNs/ACSS AR coating; Before the nano-TiO2 deposited, the hardness and elastic modulus of the HSNS/ACSS AR coating are 2.3 GPa and 56.3 GPa, respectively, the hardness of the AR coating is significantly improved after the nano-TiO2 deposited, the hardness and elastic modulus of the HSNs@TiO2/ACSS AR coating are 3.3 GPa and 55.2 GPa, respectively. The nano-TiO2 deposited on HSNs by sol-gel method could effectively improve the hardness of AR coatings, so the environmental applicability of AR coatings is expected to be further improved.
Key words
AR coatings; sol-gel; hollow SiO2; nano-TiO2; hardness; transmittance
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HUANG Fen-chao, JIAO Jian, CHENG Hao, WANG Jin, WANG Jia.
Effect of TiO2 on the Hardness of Hollow Silica Antireflection Coating[J]. Surface Technology. 2021, 50(4): 191-197
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