新型溶胶-凝胶二氧化硅微孔增透膜的制备及性能研究

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

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。

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.