Phase Behavior of the Binary Mixtures of Pyrene and Polymers with and without Aromatic Side Groups.

The phase behaviors and thermodynamic properties of pyrene and polymers with and without aromatic side groups are studied using the differential scanning calorimetry technique. Polymers with aromatic side groups showed a relatively larger degree of depression of melting temperature, which suggests higher compatibility with pyrene. Using the enthalpy of melting of pyrene crystals, we could extract the compositions of polymer-rich phases. Surprisingly, the polymers with aromatic hydrocarbons showed much-pronounced miscibility with pyrene at symmetric compositions. In contrast, the polymers without aromatic side groups did not show the composition-dependent miscibility enhancements. These results suggest that the compatibility between polymers and polyaromatic hydrocarbons can be effectively tuned by judicious choice of chemical functional groups of polymers.