以正硅酸乙酯为原料,采用溶胶-凝胶法制备SiO₂溶胶,通过提拉法涂制多孔SiO₂减反膜,并在多孔SiO₂减反膜上涂制一层甲基三乙氧基硅烷(MTES)预聚体。通过疏水的MTES预聚体涂制在多孔SiO₂减反膜上,对多孔SiO₂减反膜的表面进行改性,以提高膜层的环境稳定性。经过表面改性的复合膜层的透过率峰值可达99.67%,折射率为1.231,水接触角达123.6°,在相对湿度为95%的环境中放置475 d后膜层的峰值透过率为99.09%,稳定性提高明显。膜层表面平整,激光损伤阈值约为24.5 J/cm ²。

SiO2 sol is prepared using the sol-gel process with tetraethyl orthosilicate as the precursor, and the porous SiO2 antireflective coating is fabricated using the dip coating method. Further, the surface of the SiO2 coating is covered using a methyltriethoxysilane (MTES) prepolymer. The objective of the experiment is to use the hydrophobic MTES prepolymer film as a cover of the surface of the SiO2 coating and to modify the surface of the coating. Ultimately, we intend to improve the environmental stability of the porous SiO2 coating. Thus, an surface-modified composite coating exhibiting a peak transmission of 99.67%, refractive index of 1.231, and water contact angle of 123.6° is obtained. Furthermore, the peak transmission of the coating becomes as high as 99.09% and its stability considerably improves after being maintained at a relative humidity of approximately 95% for 475 days. It can also be observed that the modified coating surface is smooth and that the laser-induced damaged threshold is 24.5 J/cm 2.