Preparation and optical properties of polystyrene nanocapsules containing photochromophores

Polymeric nanocapsules were prepared by the convenient one-step miniemulsion polymerization. Aqueous miniemulsion was obtained by mixing monomer, photochromophore, and initiator, and then adding the solution to an aqueous solution of surfactant and water, followed by ultrasonification. As the monomer was polymerized at 60 degreesC, polymeric nanocapsule particles were obtained. The morphology of the prepared nanocapsules was studied by transmission electron microscopy and showed core/shell structure with average diameter of 50-150 nm. Different types of photochromophores and initiators were applied to prepare nanocapsules and their effects on the morphology of the capsules were investigated. Thin films on glass substrates were prepared by spin coating, using a diarylethene containing nanocapsule solution. The color of the thin film was changed immediately to red upon irradiation with a UV light, which was bleached completely to an original state with the light of 500-650 nm. (C) 2002 Published by Elsevier Science B.V.