Circular Selective Reflection of Light Proving Cholesteric Ordering in Thin Layers of Chiral Fluorene Polymers

Thermally annealed and aligned thin films of polyfluorene and two other chiral fluorene copolymers preferentially reflect left-circular-polarized light with wavelengths just below the onset of the lowest-allowed pi-pi* optical transition. This provides evidence for a left-handed cholesteric arrangement of the polymer chains in the film.