SiO₂表面自组装单分子层的疏水改性研究

Research on Hydrophobic Modification of Self-Assembled Monolayers on SiO₂ Surfaces

摘要: 随着纳米技术的快速发展，对多功能材料的需求促使科研人员不断探索如何在微观层面上控制材料的表面结构和功能。本文使用食人鱼溶液和RCA标准清洗液对基片表面进行彻底地清洗、氧化和羟基化，采用提拉法在SiO₂表面自组装上一层十八烷基三氯硅烷(OTS)分子层，在120℃条件下加热1.5 h，对自组装膜进行热固化，得到排列紧密且取向有序的疏水单分子膜。测试结果显示，自组装前后基材表面的粗糙程度基本保持不变，表面水润湿性向疏水状态转变。自组装膜在强酸、高盐和有机溶剂等环境下能保持性能稳定持续256 h，在强碱环境下16 h就会完全损失，单分子膜在经历了1000 r的摩擦损伤后仍能保持90˚的疏水效果，测试结果体现出改性得到的自组装单分子层(SAM)具有一定的物理和化学稳定性。

Abstract: With the rapid development of nanotechnology, the demand for multifunctional materials has propelled researchers to continuously explore how to control the surface structure and functionality of materials at the microscopic level. In this study, the substrate surface was thoroughly cleaned, oxidized, and hydroxylated using piranha solution and RCA standard cleaning solution. A layer of octadecyltrichlorosilane (OTS) molecules was self-assembled on the surface of SiO₂ using the dip coating method, and the self-assembled film was thermally cured at 120˚C for 1.5 h, resulting in a densely packed and orientationally ordered hydrophobic monolayer. Test results showed that the surface roughness of the substrate remained largely unchanged before and after self-assembly, with a transition from surface hydrophilicity to hydrophobicity. The self-assembled film maintained stable performance in strong acid, high salt, and organic solvent environments for 256 h, but completely degraded after 16 hours in a strong alkaline environment. Even after experiencing 1000 r of frictional damage, the monolayer film still maintained a hydrophobicity of 90˚, indicating a certain level of physical and chemical stability of the self-assembled film.