Gibbs energy and entropy of mixing

The Gibbs energy in the final state is given by the addition rule, Eq. (11.9)  

The Gibbs energy of mixing, AG ix = Gfi ai — Gj itiaiJ on inserting the values of Gfinai and Ginitiai, becomes 

Differentiation of = finai initial with respect to temperature, yields 

A plot of the entropy of mixing of a binary mixture according to the equation 

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Flory and Huggins have shown that if the amorphous (i.e. noncrystalline) polymer and the solvent mix without any energetic effects (i.e. athermal behavior), the change in Gibbs energy and entropy of mixing are given by the remarkably simple expression ... 

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