title: Molecular structure of polystyrene at Air/Polymer and Solid/Polymer interfaces
abstract: 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.
authors.affiliation: The University of Akron, Akron, Ohio 44325, USA.
authors.initials: KS
authors.lastname: Gautam
authors.initials: AD
authors.lastname: Schwab
authors.initials: A
authors.lastname: Dhinojwala
authors.initials: D
authors.lastname: Zhang
authors.initials: SM
authors.lastname: Dougal
authors.initials: MS
authors.lastname: Yeganeh