Micelles and nanoparticles : a novel approach to photonic crystal synthesis

Abstract

Photonic crystals are an interesting class of materials that hold much promise for future lighting designs. The unique structure of a photonic crystal, a periodic array of high and low dielectric material, creates optical band gaps within the material; in other words, certain wavelengths of light are unable to propagate through the material. Despite the promise of these materials in a variety of applications, usage is currently limited to laboratory environments due to the high cost and low output of current microfabrication techniques used to synthesize photonic crystals. This study aims to simplify the synthesis process by exploiting self-assembly techniques in micelle formation and self-ordering of colloidal spheres. Zirconia nanoparticles with a diameter of 4 nm were synthesized and coated with polymer brushes to prevent agglomeration. PS-b-PAA block copolymer micelles were then precipitated around the nanoparticles creating a micelle with a high dielectric core and a low dielectric shell. Transmission electron microscopy was used to verify successful nanoparticle encapsulation while scanning electron microscopy and dynamic light spectroscopy were used to determine micelle size and dispersity. An attempt was made to self-order micelles into an FCC-like structure using convective assembly. It was found that the micelles did not order. The size dispersity is currently too great to create the precise structure necessary for a photonic crystal.