Preparation and Characterization of Multi-layer Structures of Polymeric Colloid Nano-particles

Due to their periodic structures, three dimensional photonic crystals possess some useful optical properties such as wave guiding. Sandwiching these structures between multilayered polymer films improves such properties compared to those of single-layer films because they form a nano structure. In the present investigation polymethyl methacrylate and polystyrene were dissolved in proper solvents namely, acetone and cyclohexane(plus 5ml carbon tetrachloride per 95ml of cyclohexane). Solutions and suspension of nano particles were spin-casted rotationally using specially designed machine to produce a periodic structure. The optical properties of the cast films were studied using spectrophotometric techniques. It was found that cladding three-dimensional polymer films induced a color change. A color-shift from blue to green was found to be related to refraction of light amongst polymer layers. J. Color Sci. Tech. 5(2011), 69-75© Institute for Color Science and Technology.