Structure and properties of polymers in concentrated solution

The mean-squared radius of gyration of a linear chain molecule in the concentrated-solution regime is proportional to the number of mers in the macromolecule. The thermodynamic properties of the solution depend on the interaction between the solvent molecules and the mers. To facilitate the discussion of these interactions, Flory chose to divide the chain molecule into 

The solution is also characterized by the number of nearest neighbors for each solvent molecule, z. This simple lattice model is able to predict many of the thermodynamic properties of concentrated polymer soluhons. For the local structure to be in the so-called mean field limit, the polymer volume fraction should exceed approximately 10%. 

The details of the Flory-Huggins tiieory of polymer solutions are presented in Section 7.2. While quantitative agreement with experimental results is only fair, the theory does predict an upper crihcal soluhon temperature for soluhons in poor solvents. Explicit calculahons of the spinodal curve and the binodal coexistence curve are presented. 

The thermodynamic properhes of concentrated soluhons can be measured using light scattering. The apphcahon of the Flory-Huggins theory to this experimental situahon is presented in Sechon 7.4 

Experimental studies of concentrated polymer soluhons reveal that most binary liquid mixtures display a lower crihcal soluhon temperature. A theory including equahon of state contribuhons was developed by Orwoll and Flory. i This theory is presented and discussed in Sechon 7.5 

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