Negative entropy,energy, and heat capacity in connection with surface tension: Artifact of a model or real?

It is only byneglecting self-adsorption (a treatment referred to as “pure-energy,” PE) that one gets textbook thermodynamics of a surface, based upon the tensionL as a function of temperatureT, and one finds negative specific heat for hot water. Any lower critical point and PE provides the other exciting negatives: nicotine-and-water is an example. In order toinclude adsorption,L must be known in terms ofT and chemical potentials asindependent variables; this forces measurement of the tension of curved menisci. Will the minus signs remain?