NMR relaxation and solvation equilibrium in the ternary system CCl4-polymethylmethacrylate-benzene

2007

In the ternary system CCl4-PMMA-benzene, benzene is preferentially adsorbed in the solvation shell of the polymer. One solvation equilibrium constant allows a satisfactory description of the preferential solvation for a large range of solvent compositions. The nuclear magnetic relaxation time T1 of benzene protons was measured for different values of the polymer concentration. The measurements are compared with analogous measurements in the system C6D6-PMMA-C6H6 where no preferential solvation is to be expected. For the system CCl4-PMMA-benzene the resulting dimensionless solvation equilibrium constant is K = c32c10/c12c30 = 2.5 ± 0.5 where c10 is the CCl4 concentration in the “free” solven…