Shanghai Key Laboratory of Special Artificial Microstructure Materials and Technology & School of Physics Science and Engineering, Tongji University, Shanghai 200092, PR China.
Shanghai Key Laboratory of Special Artificial Microstructure Materials and Technology & School of Physics Science and Engineering, Tongji University, Shanghai 200092, PR China.
J Colloid Interface Sci. 2019 Nov 1;555:124-131. doi: 10.1016/j.jcis.2019.07.056. Epub 2019 Jul 22.
Environmental stability is of great interest for sol-gel porous antireflective (AR) coatings. In this work, sol-gel silica AR coatings with excellent environmental stability were prepared via ammonia vapor treatment (AVT) combined with organosilane (hexamethyldisilazane (HMDS) or hexadecyltrimethoxysilane (HTMS)) vapor treatment. The surface free energy (SFE) of the coatings treated with different approaches was estimated through Owens-Wendt method combined with Wenzel equation from the contact angles of water, glycerol and diiodomethane. Scanning electron microscope and Fourier transform infrared spectroscopy were employed to study the surface morphology and chemical composition of the silica coatings treated with different methods. The silica coatings treated by combined vapor phase method possess the SFE of 24.11 mJ·m for N-HD-SiO and 34.18 mJ·m for N-HT-SiO. After being placed in a 90%RH humid environment for 2 months, the peak transmittance of BK7 glasses coated with N-HD-SiO and N-HT-SiO only decreases by 0.58% and 0.95%, respectively. Meanwhile, N-HD-SiO and N-HT-SiO coated BK7 glasses also show quite stable optical transmittance after exposure to a vacuum oil environment for 2 months. The mechanism of the combined vapor phase surface treatment is discussed based on the combination analysis of surface morphology, chemical composition and SFE of the coatings.
环境稳定性对于溶胶-凝胶多孔抗反射（AR）涂层非常重要。在这项工作中，通过氨蒸汽处理（AVT）结合有机硅烷（六甲基二硅氮烷（HMDS）或十六烷基三甲氧基硅烷（HTMS））蒸汽处理，制备了具有优异环境稳定性的溶胶-凝胶二氧化硅 AR 涂层。通过 Owens-Wendt 方法结合 Wenzel 方程，从水、甘油和二碘甲烷的接触角估算了不同处理方法的涂层的表面自由能（SFE）。采用扫描电子显微镜和傅里叶变换红外光谱研究了不同方法处理的二氧化硅涂层的表面形貌和化学组成。通过组合气相法处理的二氧化硅涂层具有 N-HD-SiO 的 SFE 为 24.11 mJ·m 和 N-HT-SiO 的 SFE 为 34.18 mJ·m。将涂有 N-HD-SiO 和 N-HT-SiO 的 BK7 玻璃在 90%RH 的潮湿环境中放置 2 个月后，其峰值透过率仅分别降低了 0.58%和 0.95%。同时，N-HD-SiO 和 N-HT-SiO 涂覆的 BK7 玻璃在暴露于真空油环境 2 个月后也表现出相当稳定的光学透过率。基于涂层的表面形貌、化学组成和 SFE 的综合分析，讨论了组合气相表面处理的机理。
