ABSTRACT
It is not our intention of state thermodynamics of dispersions in detail here. More attention is paid to the statistical thermodynamic treatment of solvent-solute interactions in nonideal solutions. Models dealing with these interactions related to the second virial coefficient such as excluded volume model, Flory-Huggins, and SCF field theories are the main content of this chapter. We begin with the derivation of the relationship between the chemical potential and osmotic pressure. One of the most basic quantities in thermodynamics is the chemical potential 1". In the thermodynamic treatment of multicomponent phase equilibria, the chemical potential Jl-i is defined as the partial molar Gibbs free energy with respect to component i at constant pressure p and temperature T, namely,
(VG) 1"- - i - vni p,T,nj±1
Physically, the chemical potential is the coefficient that measures the change in Gibbs free energy of a system per mole of component i if the temperature, pressure, and number of moles of all components other than the ith remain unchanged. For a pure substance, Jl-i is equal to the Gibbs free energy per mole of that substance.
