Spontaneous Formation of Left- and Right-Handed Cholesterically Ordered Domains in an Enantiopure Chiral Polyfluorene Film

Thermally annealed chiral polyfluorene films are studied by circular differential optical microscopy. We observe the presence of micrometer-sized domains displaying circular dichroism of opposite sign. Our findings suggest the spontaneous occurrence of left- and right-handed cholesterically ordered domains from an enantiopure precursor. The role of enantiopure stereo centers in the side chains of the polymer is to lower the energy of the left-handed cholesteric domains with respect to the right-handed ones.