Miscibility of Rigid-Rod and Random-Coil Macromolecules through Acid−Base Interactions

Acid−base interactions can be used to overcome the free energy barrier to the mixing of rods and coils, originating primarily from the reduced entropy of the coil conformation in the presence of rods. A study of rigid-rod polydiacetylene, carrying pyridine side groups, and sulfonated polystyrene blends, in conjunction with a modified Flory theory, shows a rich variety of observed and expected phase behavior.