Adsorbed Molecules on Solvated Layer Silicates: Surface Mobility and Orientation from ESR Studies

M. B. McBride
Department of Agronomy, Cornell University, Ithaca, New York, U.S.A.

Abstract: The adsorption of nitroxide spin probes on smectites solvated in liquids of greatly different polarity was studied using electron spin resonance (ESR) spectroscopy. Adsorbed probes demonstrate various degrees of restricted rotational motion and alignment at the silicate surfaces, depending upon the properties of the solvating liquid. The results are interpreted in terms of direct surface—molecule interaction modified by solvent competition effects. A fraction of the probe molecules is immobilized in many of the solvated clays because of small spacings between platelets. The data indicate lowered reactivity of surface-adsorbed molecules, especially in the case of hydrated smectites.

Clays and Clay Minerals; February 1977 v. 25; no. 1; p. 6-13; DOI: 10.1346/CCMN.1977.0250102
© 1977, The Clay Minerals Society
Clay Minerals Society (