New Evidence for the Formation of Molecular Complexes in Monolayers by Penetration

Abstract

THE formation of complexes of definite composition in monolayers as described by Schulman and Stenhagen¹, in particular with cetyl alcohol and sodium-cetyl sulphate, has been questioned by Harkins². Harkins did not succeed in reproducing the discontinuities on the isotherms and has expressed doubt about the existence of the corresponding complexes and the validity of the experimental results in general. In fact, the shape of the isotherms is a function of time, on account of the instability of the monolayer (collapse or solubility) ; it is possible to notice changes of behaviour, of rate of collapse, of stability and of physical state, but without much precision about the molecular areas corresponding to the different regions. I have taken up again this question of the interaction in monolayers between cetyl alcohol and sodium alkyl sulphates using a slightly different technique which removes any doubt about the existence of the 1–1, 1–2 and 1–3 complexes.