PFG NMR Self-Diffusion Study of n-Paraffins Adsorbed on Silica Gel

✍ Scribed by U. Rolle-Kampczyk; J. Kärger; J. Caro; M. Noack; P. Klobes; B. Röhl-Köhn

• Publisher: Elsevier Science
• Year: 1993
• Tongue: English
• Weight: 312 KB
• Volume: 159
• Category: Article
• ISSN: 0021-9797
• DOI: 10.1006/jcis.1993.1335

✦ Synopsis

Molecular self-diffusion is studied for several probe molecules in a sample series of Merck silica gels. The fractal interpretation of the pore size distributions from (\mathrm{N}_{2}) desorption measurements indicate that both the micro- and mesopore regions can be described as fractal regions. By varying the observation time in the PFG NMR experiment, the relationship between the mean square displacements and the diffusion time is analyzed to trace the occurrence of anomalous self-diffusion in fractal regions. A model for the structure-related self-diffusion in silica gel is proposed. 1993 Academic Press, Inc.