Illustrating consistency of different experimental approaches to probe the buried polymer/metal interface using sum frequency generation vibrational spectroscopy.

In this paper, we demonstrate our ability to directly probe the molecular structures of the buried polymer/metal interface using sum frequency generation (SFG) vibrational spectroscopy. Spectroscopic data from different experimental approaches were compared and analyzed to deduce the molecular ordering information at a buried polymer/metal interface, i.e. the poly(n-butyl methylacrylate) (PBMA)/silver (Ag) interface. Solid spectroscopic evidence suggested that we successfully detected the molecular vibrational signals generated from the buried PBMA/Ag interface. It was found that the side butyl methyl groups at the PBMA/Ag interface are polar-ordered and have different orientational ordering from those at the PBMA surface in air. We believe that this study will provide a useful experimental and analytical framework for the SFG spectroscopy to probe the buried polymer/metal interfaces in the future.