The chiroptical properties of a thermally annealed film of chiral substituted polyfluorene depend on film thickness

CD of fluorene homopolymer bearing chiral-3,7-dimethyloctyl sidechains on the 9 position of the fluorene moiety was studied. Chiral polyfluorene films of differing thickness were annealed at 150 DegC for 2 h under a nitrogen atm. The degree of circular polarization in the absorption of light by these films was found to depend strongly on film thickness. This indicates that the exceptionally high dissymmetry ratios obsd. for these films originate on a nanoscopic level and are related to the long range correlation in the polymer chain orientation induced by annealing the film in its liq. cryst. phase at high temp. [on SciFinder (R)