How formaldehyde interacts and reacts with chromium and chromium oxide surfaces: A model for chromium-polyimide binding
| Autor: | F. Emmi, Stephen R. Cain |
|---|---|
| Rok vydání: | 1990 |
| Předmět: |
Inorganic chemistry
Formaldehyde chemistry.chemical_element Surfaces and Interfaces Condensed Matter Physics Surfaces Coatings and Films Metal chemistry.chemical_compound Chromium chemistry Covalent bond visual_art Materials Chemistry visual_art.visual_art_medium Molecule Chromium hydride Lone pair Polyimide |
| Zdroj: | Surface Science. 232:209-218 |
| ISSN: | 0039-6028 |
| DOI: | 10.1016/0039-6028(90)90600-d |
| Popis: | Chemical interactions of chromium and chromium oxide with carbonyl functional groups of a polyimide chain were investigated theoretically. Band calculations of the extended Huckel type were performed on model systems. The chromium (chromium oxide) surface was represented by a three-layered slab of material, and for computational economy, the polyimide carbonyls were represented by the formaldehyde molecule. Results suggested that while formaldehyde binds to Cr 2 O 3 via its oxygen lone pair electrons, it binds to metallic Cr in a π or η 2 (dihapto) fashion. Further, the calculations indicated that formaldehyde was susceptible to decomposition when bound to clean Cr, but was not susceptible to decomposition when bound to Cr 2 O 3 . These differences were attributed to the relatively lower Fermi energy of Cr 2 O 3 . By analogy, the imide groups in polyimide may be substantially decomposed at the polyimide/Cr interface, with strong covalent bonding between the metal and the fragmented polymer. |
| Databáze: | OpenAIRE |
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