What is "the disjoining pressure" and What is "the Hamaker function".
Where did you read about these concepts ?
Can you give a reference to a text where they appeared ?
This paper might help to explain the Hamaker function (and Hamaker equation, Hamaker constants).
As for disjoining pressure - see "Effect of van der Waals forces on molecularly thin lubricant in the magnetic storage head-disk interface"
Also see - Lifsh!tz theory (where ! = i, in order to avoid auto-censor )
van der Waals Interaction, Surface Free Energies, and Contact Angles: Dispersive Polymers and Liquids
which mentions Lifsh!tz theory and Hamaker equation and constants.
See also - On the calculation of disjoining pressure isotherms for nonaqueous films.
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