BET analysis of thermal accommodation coefficients obtained via measurements of the Onsager heat of transport

The non-linearity of plots of ΔP versus ΔT in measurements of the Onsager heat of transport at a gas–liquid interface was previously attributed to a difference in thermal accommodation coefficients between dry and wetted states of the solid surface at which ΔT was applied. This implies that the accommodation coefficient should be a measure of the fractional coverage of the upper surface, as described by Brunauer–Emmett–Teller (BET) theory. A BET treatment of our accumulated ΔP versus ΔT data has given values for the average number of layers of adsorbed liquid in the wetted area for aniline, n-heptanol, water, and p-tert-butyltoluene.