提出了一种原位测量气,液界面Langmuir单分子膜拉曼光谱的新方法,即利用SERS技术,通过降低亚相的方法来获得气,液界面Langmuir单分子膜的原位拉曼光谱.利用这种方法,用原位拉曼光谱测量系统得到了信噪比较好的十八胺及二棕榈酰磷脂酰胆碱单分子膜的拉曼光谱,在分子水平上获取了单分子膜中的结构信息.
A new approach for the acquisition of in situ Raman spectra of Langmuir monolayers at air-water interface with minimal interference was presented. An in situ Raman instrument was designed, which comprises a Raman spectrometer (JY-U1000), a micro Langmuir-Blodgett trough, and a CCD imaging system. By lowering the subphase slowly until Langmuir monolayer deposited on a surface-enhanced Raman scattering (SERS) substrate that was placed under subphase in advance, Raman spectra of Langmuir monolayers of octadecylamine (ODA) and dipalmitoylphosph-atidylcholine (DPPC) have been acquired with good signal-to-noise ratio. These spectra present informations of the headgroup interaction and the ordering degree of alkane chains at different surface pressures. This new method could expand SERS application in the study of Langmuir monolayers at the air-water interface.