Molecular ordering of phenyl groups at the buried polystyrene/metal interface

Understanding molecular structures of buried polymer/metal interfaces is important for the design and development of polymer adhesives used in advanced microelectronic devices and polymer anticorrosion coatings for metals. The buried interfacial molecular structure between polystyrene (PS) and silver (Ag) was investigated using infrared-visible sum frequency generation (SFG) vibrational spectroscopy via a "sandwiched" sample geometry. SFG resonant signals from the phenyl C-H stretching vibrational modes were detected from the PS/Ag interface, suggesting that the PS phenyl groups at this buried polymer/metal interface are ordered. Spectral analysis indicated that the phenyl groups at the buried PS/Ag interface tilt toward the interface, pointing away from the Ag side.