Chirality amplification of syndiotactic polystyrene induced circular dichroism chiral film in δ form upon annealing

The induced circular dichroism (ICD) syndiotactic polystyrene (sPS) chiral films in sPS δ phase were prepared and the chirality of the ICD sPS films upon annealing at different temperature was investigated. The sPS δ crystals in the ICD films transform into γ and then into α crystals as those of achiral sPS δ crystals during annealing at different temperature. The CD signal intensity at λ of 200 nm remains unchanged during the δ to γ crystalline transformation, but enhanced tremendously during the γ to α crystalline transformation. The amplification CD signal attributes to the closer package of the phenol rings in sPS α phase than that in sPS δ and γ phases. The lamellae grown at a temperature above the γ to α transition follow the chiral aggregation structure, which also contribute to the amplification of the CD signal.