Molecular Structure of Graphite/Polyimide Interphases
Abstract
The molecular orientation of adsorbed polyimides and model compounds with respect to highly oriented pyrolytic graphite (HOPG) surfaces was determined by reflection-absorption infrared (RAIR) spectroscopy. As the thickness of pyromellitic diimide (PMDI) films decreased, bands near 766 and 729 cm-1, which were assigned to the CNC out-of-plane bending modes, were relatively strong in the spectra, demonstrating that PMDI was adsorbed flat-down with the imide rings parallel to the HOPG surface. As the thickness of N,N'- diphenylpyromellitic diimide (DPPMDI) films was decreased, bands near 1785 and 1722 cm-1, which were assigned to the C=O stretching modes were relatively strong in the RAIR spectra. Moreover, bands near 869, 841, 742, and 686 cm-1 attributed to the out-of-plane bending modes of monosubstituted benzene rings became considerably stronger It was suggested that the DPPMDI molecules nearest to the HOPG surface were adsorbed edge-on with the carbonyl groups perpendicular to the surface and with the monosubstituted benzene rings parallel to the surface.
Document Details
- Document Type
- Technical Report
- Publication Date
- May 22, 1992
- Accession Number
- ADA251497
Entities
People
- F. James Boerio
- J. T. Houng
- W. H. Tsai
Organizations
- University of Cincinnati