Polymeric morphologies and fluorescence of poly(p-phenylene) films by self-assembly

- Well-defined conjugated polymeric nanowires can be formed from the diluted solution in the solvent vapor.
- Solvents and the concentrations can affect the morphologies and the optical properties of the films.
- The optical properties are influenced by the conformations and aggregations of the polymer though the solvent-solute interaction and the solute-solute interaction from the solutions.

Polymer morphologies in thin films strongly depend on the state of the solution and the film processing conditions, which lead to significant impacts on the optoelectronic properties. In this work, the morphologies of poly(p-phenylene) films are investigated by concentration-dependent fluorescence spectroscopy and scanning electron microscopy combined with the contact angle tests. We find that the well-defined nanowires of the hairy-rod conjugated polymer can be self-assembled in different good solvent vapor atmospheres from the dilute solutions. The driving force of aggregation would be the side-chain entanglement and the intermolecular π-π interactions, which are sensitive to concentration. Moreover, the optical properties are strongly affected by the polymer concentration, which is the main factor to form different conformations and aggregations of polymers. These results are valuable for the intrinsic properties of poly(p-phenylene) and the potential application in optoelectronic devices.

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