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Enhancement of photochemical grafting of terminal alkenes at surfaces via molecular mediators: The role of surface-bound electron acceptors

Colavita, Paula E. and Streifer, Jeremy A. and Sun, Bin and Wang, Xiaoyu and Warf, Patrick and Hamers, Robert J. (2008) Enhancement of photochemical grafting of terminal alkenes at surfaces via molecular mediators: The role of surface-bound electron acceptors. JOURNAL OF PHYSICAL CHEMISTRY C, 112 (13). pp. 5102-5112.

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Official URL: http://pubs.acs.org/doi/abs/10.1021/jp711167n

Abstract

The use of ultraviolet light to functionalize the surface of carbon-based materials with terminal alkenes has emerged as a way to overcome the high chemical stability of these surfaces to create functional interfaces. It was previously shown that surface-bound trifluoroacetic acid protected 10-aminodec-1-ene (TFAAD) can be used to promote the grafting of unreactive alkenes using 254 nm light, but the mechanism by which this enhancement occurs was not understood. Here, we present a detailed study of how surface-bound TFAAD enhances the grafting of organic molecules to the surface of hydrogen-terminated amorphous carbon. Infrared reflection absorption spectroscopy, X-ray photoelectron spectroscopy, scanning electron microscopy, and atomic force microscopy experiments show that pregrafting TFAAD onto carbon surfaces greatly enhances the subsequent grafting of 1-dodecene, dodecane and dodecane-d(26) by locally facilitating photoemission of electrons. Using a photopatterned TFAAD ``seed'' layer, we demonstrate that subsequent grafting of these hydrocarbons is enhanced in regions immediately adjacent to the seed and proceeds almost exclusively parallel to the carbon surface. The roles of liquid-phase radical species, valence band holes, and the photochemical fragmentation of surface species in controlling the overall reaction mechanism are discussed.

Item Type:Article
Uncontrolled Keywords:carbon-based materials - spectroscopy - microscopy
Subjects:Analytical Science > Microscopy and probe methods
Material Science > Nanochemistry
ID Code:5956
Deposited By:IoN
Deposited On:01 Sep 2009 11:28
Last Modified:01 Sep 2009 11:28

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