Shanghai Key Laboratory of Special Artificial Microstructure Materials and Technology & School of Physics Science and Engineering , Tongji University , Shanghai 200092 , P. R. China.
College of Science , University of Shanghai for Science and Technology , Shanghai 200093 , P. R. China.
ACS Appl Mater Interfaces. 2019 Oct 9;11(40):37084-37093. doi: 10.1021/acsami.9b12370. Epub 2019 Sep 30.
Mechanical and contamination-resistant properties are the most crucial and challenging issues that impede the practical applications of sol-gel antireflective (AR) coating. In this paper, we report a low-temperature vapor surface treatment strategy for the partial embedding and surface functionalization of silica nanoparticles (SNPs) on flexible polymeric glass substrates. SNPs, which were synthesized via the Stöber method, were partially embedded into the polymeric glass substrates by vapor-phase surface treatment using volatile chloroform. Further vapor-phase surface treatments by water and hexamethyldisilazane (HMDS) were applied successively to achieve high trimethylsilyl coverage of the SNPs. The HMDS modification could convert the polar surface of SNPs to a nonpolar surface for contamination resistance, while ammonia, as a byproduct generated, could help to cross-link the SNPs via self-condensation of silanol groups, thus hardening the coating. The SNP-CWH coated polymethylmethacrylate (PMMA) substrate shows an average transmittance of 98.62% in the wavelength region of 400-800 nm, which is 6.32% higher than that of the uncoated bare PMMA. The AR performance of SNP-CWH coated PMMA shows almost no degradation after 100 times of rubbing or bending, indicating the greatly enhanced abrasion resistance and flexibility. Furthermore, the SNP-CWH coating exhibits superior contamination-resistant property, where the transmittance curve of the coated substrate displays a barely noticeable change after exposure to a "dirty" environment with water and organic contaminants for 6 months. This work paves a new way for developing mechanically robust and contamination-resistant AR coating for polymeric substrates.
机械稳定性和抗污染性是阻碍溶胶-凝胶抗反射（AR）涂层实际应用的最关键和最具挑战性的问题。在本文中，我们报告了一种在柔性聚合物玻璃基底上进行二氧化硅纳米颗粒（SNPs）局部嵌入和表面功能化的低温气相表面处理策略。通过Stöber 法合成的 SNPs 通过使用挥发性氯仿的气相表面处理部分嵌入聚合物玻璃基底中。进一步通过水和六甲基二硅氮烷（HMDS）的气相表面处理，成功地实现了 SNPs 的高三甲硅基覆盖率。HMDS 修饰可以将 SNPs 的极性表面转化为抗污染的非极性表面，而作为副产物生成的氨可以帮助 SNPs 通过硅醇基团的自缩合进行交联，从而使涂层变硬。SNP-CWH 涂层的聚甲基丙烯酸甲酯（PMMA）基底在 400-800nm 的波长范围内表现出平均透光率为 98.62%，比未涂层的裸 PMMA 高 6.32%。SNP-CWH 涂层的 AR 性能在 100 次摩擦或弯曲后几乎没有降解，表明其耐磨性和柔韧性有了很大的提高。此外，SNP-CWH 涂层表现出优异的抗污染性，在暴露于水和有机污染物的“脏”环境中 6 个月后，涂层基底的透光率曲线几乎没有明显变化。这项工作为开发用于聚合物基底的机械稳定和抗污染的 AR 涂层开辟了新途径。
