The Effect of UV Irradiation on the Transmittance Bands of Polystyrene-block-2-vinylpyrimidine

Abstract

Block copolymers have been investigated for fabricating functional nanomaterials due to their properties of self-assembly. We prepared polystyrene-b-poly(2-vinyl pyridine) (PS-b-P2VP) lamellar films which is hydrophobic block-hydrophilic polyelectrolyte block polymer have 57kg/mol-b-57kg/mol. The lamellar stacks are obtained by exposing the spin coated film under chloroform. The P2VP blocks were then quaternized and crosslinked to various extents using 5wt% of iodomethane. PS-b-P2VP films showed excellent photonic bands at 630nm after swelling with ethanol and 661nm with water after treated with Calcium Carbonate. We observed significant band shift from 663nm (deep red) to 531nm (green) during UV-irradiation for 40 seconds. The phase separation process of BCP was very sensitive to the film thickness. The quarternized films with thickness varied from 0.43 mu m (446nm transmittance minimum) to 0.25m (478nm transmittance minimum). This study shows that the total film thickness and UV irradiation effectively change the transmittance band by affecting the thickness of layers consisting of PS-b-P2VP photonic crystals.