Synthesis and Optical Properties of Polymeric Opals with Nanometric Core- Shell Structure

In this research, polymeric photonic crystals with fcc packing structure were prepared and studied. Firstly, monodispersed colloidal spheres with core-shell structure were synthesized; they consisted of a polystyrene (PS) core and a copolymer shell of butyl acrylate (BA) and methyl methacrylate (MMA). The sample with total solid content of 32% was obtained and total conversion of polymerization was about 98 %. Then, the latex was coagulated in methanol, filtered and dried. After complete drying, the samples were hot pressed to make thin films of one millimeter thickness. In this crystallization procedure, the soft shells of latex spheres permit melt-like flow and the cores were organized to fcc packing structure in the elastomeric matrix. Uv spectrometer measurement showed two different refracted picks before and after press proving ordered structure of particles after hot press molding of dried latex.