Open AccessThe adsorption of vapours at plane surfaces of mica II. Heats of adsorption and the structure of multimolecular films
Author(s) -
D. H. Bangham,
S. Mosallam
Publication year - 1938
Publication title -
proceedings of the royal society of london. series a, mathematical and physical sciences
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.814
H-Index - 135
eISSN - 2053-9169
pISSN - 0080-4630
DOI - 10.1098/rspa.1938.0111
Subject(s) - adsorption , mica , monolayer , condensation , saturation (graph theory) , benzene , vapours , chemistry , vapor pressure , chemical engineering , materials science , organic chemistry , thermodynamics , nanotechnology , composite material , physics , mathematics , combinatorics , engineering , neuroscience , biology
In a previous paper, where the results of adsorption measurements with known surface areas of mica were recorded (Bangham and Mosallam 1938), attention was focused on the range where the first molecular layer is yet incomplete. The present communication deals mainly with the transition to a thicker covering as the pressure of vapour is increased towards saturation. Conclusive evidence has already been given that the very large increase in the adsorption of benzene and carbon tetrachloride near saturation is not attributable to the condensation of liquid, either between contiguous faces of the mica strips (in those experiments where these were not separated by wires) or in incipient cleavages at their edges. The adsorbed films were found incapable of acting as nuclei of condensation for the bulk liquids, and were proved to constitute a phase thermodynamically distinct from the latter. Nevertheless, as the sequel will show, the adsorption energy is very little different from the normal heat of condensation once the first monolayer is complete, and there is evidence which suggests that the densities of the multimolecular films may not differ widely from those of the bulk liquids.