A Simple Route to Multimodal Composite Nanoparticles

A new synthetic method, based on miniemulsion polymerization, for the preparation of composite polymer-inorganic nanoparticles was investigated. Preliminary experiments were carried out to demonstrate that the synthetic approach produces well-defined composite latex particles based on just a single type of inorganic nanoparticle. A series of coencapsulation experiments were carried out using MnFe 2O 4 particles with 11 nm average diameter and four different populations of Au nanoparticles, with average diameters ranging from 13 to 46 nm. The composite nanoparticles obtained from miniemulsion polymerization were stabilized by charged surface groups and remained well dispersed in aqueous solution. UV-vis spectroscopy of the multimodal composite particles confirmed the incorporation of Au nanoparticles with their signature absorption maximum at δ520 nm while the magnetism conferred by the incorporated MnFe 2O 4 was evident from the ability to harvest the composite particles using a simple bar magnet.