film-sorption-isotherm data:
Xeq ¼ Xo K Caw
ð1KawÞð1Kaw þ1CawÞ ð4Þ
where Xeq is the humidity content of the sample (dry base) in the
equilibrium (g H2O g1 dry film) at a given aqueous activity (aw),
Xo is the moisture content (dry base) of the monolayer (g H2O g1
dry film), C is the Guggenheim constant associated with the
sorption heat of the monolayer, and K is the constant associated
with the sorption heat of multilayers. The parameters of the model
(Xo, K, and C) were determined by the quadratic regression of
aw/Xeq versus aw by means of the OriginPro 8 SR0 v8.0724 software
(OriginLab Corporation, USA).
2.