| AVS 55th International Symposium & Exhibition | |
| Surface Science | Thursday Sessions |
| Session SS-ThP |
| Session: | Poster Session |
| Presenter: | J.S. Becker, University of Chicago |
| Authors: | J.S. Becker, University of Chicago M.A. Freedman, University of Colorado, Boulder S.J. Sibener, University of Chicago |
| Correspondent: | Click to Email |
The surfaces of thin polymer films are a complex and dynamic macromolecular interface that have attracted significant attention. Presently, there is poor understanding regarding the modification of dynamics and crystallization at the free polymer surface by dimensional confinement of the polymer into a supported thin film. Helium atom scattering is a uniquely surface sensitive and non-destructive probe of vibrational motion and structure at complex interfaces. Elastic helium scattering reveals surface stiffening of amorphous poly(methyl methacrylate) (PMMA) in molecularly thin films as a function of diminishing film thickness. Furthermore, collisional energy transfer characteristics measured from amorphous PMMA, polystyrene, and polybutadiene films show remarkably similar lineshapes and temperature induced intensity decays, owing largely to the common methylene groups presented at the surface. Additionally, helium scattering provides exquisite sensitivity to surface order and crystallinity. Surface crystallization is presently being measured in thin films comprised of poly(ethylene terephthalate) and compared with related data obtained from glancing-angle Fourier-Transform Infrared Spectroscopy measurements acquired in an ultra high vacuum environment.