Solvent Effects on the Self-Assembly of 1-Bromoeicosane on Graphite. Part I. Scanning Tunneling Microscopy
| Autor: | Boaz Ilan, Thomas Müller, Thomas A. Baker, Bruce J. Berne, George W. Flynn, Adam Rothman, Tova L. Werblowsky, Gina M. Florio |
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| Rok vydání: | 2009 |
| Předmět: |
Chemistry
Intermolecular force Analytical chemistry Surfaces Coatings and Films Electronic Optical and Magnetic Materials law.invention Crystallography General Energy Lamella (surface anatomy) law Monolayer Molecule Lamellar structure Graphite Physical and Theoretical Chemistry Solvent effects Scanning tunneling microscope |
| Zdroj: | The Journal of Physical Chemistry C. 113:3631-3640 |
| ISSN: | 1932-7455 1932-7447 |
| DOI: | 10.1021/jp809216w |
| Popis: | Self-assembled monolayers of 1-bromoeicosane (BrC20H41) have been investigated at the vacuum−graphite and liquid−graphite interfaces using scanning tunneling microscopy (STM) (Part I) and theory (Part II). Under ultrahigh vacuum conditions at 80 K, STM images show 1-bromoeicosane in a lamellar assembly structure where individual molecules are predominantly arranged with their bromine groups pointed head-to-head with a 66 ± 3° angle between the lamella direction and the molecular backbone axis. A significant degree of disorder is observed under vacuum conditions, in which head-to-tail defects are interspersed throughout the film. When 1-bromoeicosane monolayers are formed and imaged in equilibrium with solution at ∼290 K, the molecules again pack with their bromines oriented head-to-head but shift to form a nearly rectangular array. Subtle changes are observed depending on the solvent utilized, with the lamella−backbone angle varying between 81 ± 3° and 90 ± 2°, and the corresponding intermolecular spacing... |
| Databáze: | OpenAIRE |
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