Portal de Periódicos da CAPES

Molecular Structure of Polystyrene at Air/Polymer and Solid/Polymer Interfaces

2000; American Physical Society; Volume: 85; Issue: 18 Linguagem: Inglês

10.1103/physrevlett.85.3854

1092-0145

Keshav S. Gautam, Alexander D. Schwab, Ali Dhinojwala, D. Zhang, S. M. Dougal, M. S. Yeganeh,

Spectroscopy and Laser Applications

IR-visible sum-frequency generation (SFG) spectroscopy has been used in a total internal reflection geometry to study the molecular structure of polystyrene (PS) at PS/sapphire and PS/air interfaces, simultaneously. The symmetric vibrational modes of the phenyl rings dominate the SFG spectra at the PS/air interface as compared to the antisymmetric vibrational modes at the PS/sapphire interface. This indicates approximately parallel orientation of the phenyl rings at the PS/air interface while nearly perpendicular orientation at the PS/sapphire interface, with respect to the surface normal.