Modifications under Irradiation of a Self-Assembled Monolayer Grafted on a Nanoporous Silica Glass: A Solid-State NMR Characterization

• Published in: Journal of physical chemistry. C 2012-02, Vol.116 (7), p.4748-4759
• Main Authors: Le Caër, S, Brunet, F, Chatelain, C, Durand, D, Dauvois, V, Charpentier, T, Ph. Renault, J
• Format: Article
• Language: English
• Subjects: Condensed matter: electronic structure, electrical, magnetic, and optical properties; Condensed matter: structure, mechanical and thermal properties; Electronic structure and electrical properties of surfaces, interfaces, thin films and low-dimensional structures; Exact sciences and technology; Physical radiation effects, radiation damage; Physics; Structure and morphology; thickness; Structure of solids and liquids; crystallography; Surface and interface electron states; Surface states, band structure, electron density of states; Surfaces and interfaces; thin films and whiskers (structure and nonelectronic properties); Thin film structure and morphology
• ISSN: 1932-7447; 1932-7455
• DOI: 10.1021/jp211639u

Controlled pore glasses with a pore size of 8 nm are grafted with chlorodimethylsilane (ClSi(CH3)2H). The surface of the glass is carefully characterized before and after irradiation with 10 MeV electrons by solid-state NMR measurements. 1H MAS NMR experiments in one and two dimensions (2D double quantum and 2D exchange) have been used to reveal the grafting of the chlorodimethylsilane at the silica surface and evidence the formation of a homogeneous layer on the surface. Irradiation leads to a high H2 yield (3.3 × 10–7 mol/J) due to the efficient cleavage of the Si–H bond. Methane is detected in smaller quantities (5.5 × 10–8 mol/J), indicating that the Si–H bond is preferentially cleaved over the Si–C bond. The H2 production arising from −OH groups on the surface is very minor in comparison to the Si–H and Si–C radiolysis.