Rod-like Transition First or Chain Aggregation First? Ordered Aggregation of Rod-like Poly(p-phenyleneethynylene) Chains in Solution
Rod-like configuration of conjugated polymer chains with small energetic disorder has been the key to utilize the backbone as a highly electrically-conductive wires. The energetic disorder coupled with vibronic modes of the chains higher than 0.1 eV leads to localization of charges. Herein we have tracked precisely rod-like transition of poly(p-phenyleneethynylene) (PPE) chains as a function of temperature in the diluted solutions, showing steep elongation of persistence length at 230 K. The resulting rod-like configuration of PPE chains with extended electronic conjugation exhibited extremely small energetic disorder of ~70 meV, stabilized by subsequent polymer aggregate formation.