Crystallization Temperature of Diluted Polymers: Dependency on Cooling Rate and Composition

The dependency of crystallization temperature (Tc) of diluted poly(3-hexylthiophene), P3HT, with different fractions of its monomer, 3-hexylthiophene (3HT), on the cooling rate of the crystallization process and the volume fraction of diluent (φd) was investigated. Two linear functions were found for the Tc-cooling rate relation at constant φd and for the Tc-φd relation at the constant cooling rate resulting from the formation of thinner crystals and increased free volume, respectively. The difference of equilibrium melting temperature (Tme) and Tc at different volume fractions of diluent revealed that the free volume had an equal effect on decreasing Tme and Tc at a constant cooling rate.