新型溶胶-凝胶二氧化硅微孔增透膜的制备及性能研究

以正硅酸乙酯为前驱体，二甲基二乙氧基硅烷为造孔剂，采用溶胶凝胶技术在酸催化条件下制备了二氧化硅溶胶;采用提拉法在K9玻璃基片上双面镀膜，经500 ℃热处理，制备得到一种新型单层微孔二氧化硅增透膜。通过改变造孔剂加入量，膜层峰值透过率可达到99.7％，而硬度仍保持在2H以上，同时具有良好的耐摩擦性及粘附性。加速腐蚀实验表明，膜层的环境稳定性是常规膜层的10倍以上。由于该新型增透膜兼具高透过率、良好的机械性能以及很强的环境稳定性，因而在改善太阳能玻璃增透性能方面有极大的应用价值。

Study on the Preparation and Properties of Novel Silica Microporous Antireflective Coating by Sol-Gel Process

Silica sol was prepared by acid catalyzed sol-gel process using tetraethylorthosilicate (TEOS) as precursor and dimethyldietoxysilane (DDS) as pore-forming agent. A novel kind of monolayer microporous silica anti-reflective (AR) coating was obtained on K9 glass substrate by dip-coating technique and then heat treated at 500 ℃. The effects of different DDS/TEOS molar ratios on refractive index，transmittance and hardness were investigated. A positive correlation was found between the transmittance and the DDS/TEOS molar ratio due to the increasing porosity. The maximum transmittance can reach 99.7％ with the molar ratio of DDS/TEOS rising to 1∶1. Meanwhile，the refractive index was found quite close to the ideal value 1.22. Nevertheless，higher molar ratio will lead to a bad film-forming property. On the other hand，the hardness of the coatings decreased with the DDS increasing but still remained more than 2 h when the transmittance reached highest. Besides，these coatings exhibit a well abrasion-resistance and excellent adhesivity. The maximum transmittance was only dropped by 0.071% and 0.112% after abrasion for 500 and 1 000 times respectively. Accelerated corrosion tests indicated that the transmittance of traditional coatings rapidly fell down to the substrate level (～92%) after immersion for 5 min，while the transmittance of our novel coating almost linearly decreased and was kept 93.2% after 56 min. In other words，the environment-resistance of our novel silica AR coating is ten times higher than that of traditional ones. The promotions of the coating performances benefit from its micropore structure(～0.4 nm) with which water molecule can be effectively prevented. With its high transmittance，good mechanical properties and high environment-resistance，this kind of novel coating has a potential application in the field of solar glass modification to improve its anti-reflective properties.