The Optical Characteristics of 1D Lamellar Photonic Crystal with PS-b-P2VP Block Copolymer

The lamellar-forming 1-dimensional photonic films were prepared by three different molecular weight, but nearly symmetric poly(styrene-b-2-vinyl pyridine) (PS-b-P2VP) block copolymers. Propylene glycol monomethyl ether acetate (PGMEA) was used as solvent to spin-cast the films. The films were submerged into ethanol to swell P2VP block. As the molecular weight of the block copolymer increases, the film shows red-shifted color, because of longer periodic distance. In addition, the color of the films in ethanol was tuned by blending the PS-b-P2VP block copolymers.