相位敏感飞秒和频光谱技术及在高分子表界面表征的应用  

Technique of Phase-Sensitive Femtosecond Sum Frequency Generation Spectroscopy and Its Application in Polymer Surface and Interface

作　　者：王子云 李柏霖 Ziyun Wang;Bolin Li(Institutes of Physical Science and Information Technology,Anhui University,Hefei 230601,China;High Magnetic Field Laboratory(HMFL),Hefei Institutes of Physical Science(HFIPS),Chinese Academy of Sciences,Hefei 230031,China)

机构地区：[1]安徽大学物质科学与信息技术研究院,安徽合肥230601 [2]中国科学院合肥物质科学研究院强磁场科学中心,安徽合肥230031

出　　处：《高分子材料科学与工程》2024年第4期111-118,共8页Polymer Materials Science & Engineering

基　　金：国家自然科学基金资助项目(22203097)。

摘　　要：高分子材料表面是表界面科学的一个重要研究领域。然而,从分子水平上对高分子薄膜表面进行原位无损精准探测仍具有挑战性。文中自主研发了表界面敏感的共线相位敏感飞秒和频光谱,其具有分子绝对取向结构的分辨能力、高的相位稳定性和信噪比以及弱表面信号的探测能力。本系统采用35fs的宽频红外激光,一次数据采集具有较宽的光谱测试范围。将此系统应用到聚甲基丙烯酸甲酯(PMMA)、聚苯乙烯(PS)和聚己二酰己二胺(尼龙6/6)高分子薄膜表面的精准结构(绝对取向结构)的探测。结果表明,PMMA的酯甲基、PS的侧基苯环以及尼龙6/6的N—H基团在表面上有序取向且朝向空气一侧,其他基团在表面上相对无序取向或者倾向于平躺于表面上。文中开发了相位敏感飞秒和频光谱,并将其应用到了高分子薄膜表面领域,对高分子薄膜表面精准结构的认识以及表面性能的优化具有十分重要的意义。The surface of polymer materials is an important research area of surface and interfacial science.However,it is still challenging to detect the surface of polymer thin films in situ nondestructively and accurately at molecular level.In this study,a collinear phase-sensitive femtosecond sum frequency generation(SFG)spectroscopy,with the resolution of absolute molecular orientation,high phase stability,high signal-to-noise ratio,and the detectability of weak surface signal,was developed.A 35 fs broadband infrared laser was employed in this system,which has a wider spectral measurement range in one data acquisition.This system was applied to probe the precise structure(absolute orientation structure)of the surface of poly(methyl methacrylate)(PMMA),polystyrene(PS),and poly(hexamethylene adipamide)(nylon 6/6)polymer films.The results indicate that the ester methyl of PMMA,phenyl ring of PS,and N—H group of nylon 6/6 are orderly oriented on the surface and toward the air side,while other groups are relatively disordered or tend to lie down on the surface.The measurement results of different sample positions demonstrate the good experimental reproducibility and high phase stability of the system.Phase-sensitive femtosecond SFG is applied to the field of polymer film surface,which is of great significance for the understanding of the precise structure of polymer film surface and the optimization of polymer surface properties.

关 键 词：相位敏感和频光谱 高分子薄膜 表界面 

分 类 号：TQ320.721[化学工程—合成树脂塑料工业]