Solvent influence on molecular interactions in the bulk of fluorene copolymer films

The effect of intermolecular interactions between the chains of the amorphous PFO–MEH-PPV films built from toluene and tetrahydrofuran (THF) were studied by atomistic molecular dynamics simulations, applying a successive solvent removal procedure. In the good solvent toluene, the incidence of topological entanglements is more significant. While in the poor solvent, coplanar interactions between neighbouring segments of the chains were also found, which is characteristics of cohesional entanglements. Structure factor curves of the films showed three peaks associated with the microstructure of the film, as previously reported by WAX diffractogram measurements. Moreover, the good solvent promotes more flexibility in dihedral angles, and the chains become nearer to each other.