Neutron reflectivity studies of critical adsorption behaviour of the surface scaling function

Abstract

Neutron reflectometry has been employed to examine the nature of the critical adsorption surface scaling function for a near critical mixture of hexane d14 perfluorohexane adsorbing to a solid substrate from the liquid one phase region. The analysis method of Dietrich and Schack has been applied to examine the nature of the power law part of the critical adsorption surface scaling function, which has been found to behave as m z P0z amp; 8722;m as the critical point is approached. Values of m 0.514 0.018 and P0 0.90 0.04 have been obtained. These values are consistent with theoretical expectations mth 0.516 0.004; P0th 0.94 0.05 , the value determined from Monte Carlo simulations P0MC 0.866 , and other experimental determinations P0ex 0.955 0.0