Macromolecules, Vol.46, No.5, 1932-1938, 2013
Phase Transition and Gels in Conjugated Polymer Solutions
Highly efficient and prolonged coarse-grained molecular dynamics simulations revealed a previously unknown pathway of phase transition of (poor-solvent) conjugated polymer solutions, evolving from a rarely explored entangled state into elastic microgels characterized by interconnected fibrous (or arm-like) materials with locally regular segmental packing. These microgels are significant in that their dynamic and structural features are rather universal (i.e., independent of the solvents utilized), in stark contrast with the counterpart dilute/semidilute systems previously shown (and also demonstrated in this work) to be dictated by solvent-sensitive aggregate species. The overall findings shed light on the yet-unresolved gelation phenomena of conjugated polymers, reveal a striking similarity with conventional entangled flexible polymers in light of the effects of solvent and concentration, and prompt a different possibility of maneuvering their thin-film properties in optoelectronics-oriented polymer science and technology.