"Log-rolling" alignment in friction-transferred light-emitting conjugated polymer thin films

Abstract

Thin films of a water-soluble poly(phenylenevinylene) (PPV) derivative with sulfonate-containing side chains (DPS-PPV) were formed on silica substrates by a solvent-free friction transfer technique. The films were highly aggregated producing "rods" of polymer aligned perpendicular to the drawing direction. This "log rolling" is in contrast with the reported behavior of most comparable polymers, which tend to align along the drawing direction. The photophysical behavior of the friction-transferred film is also different compared with other film formation techniques of the same polymer. Comparison of the steady-state and time-resolved emission characteristics of these films with films coated b..