Location-selective incorporation of multiwalled carbon nanotubes in polycarbonate microspheres

In this study, we describe a process to produce polycarbonate (PC) microspheres and incorporate multiwalled carbon nanotubes (MWCNTs) within them location-selectively. The process, an oil-in-water (O/W) emulsion method, entails the formation of an aqueous phase with poly(vinylpyrrolidone) (PVP) and a methylene chloride phase that dissolves PC. Uniform PC microspheres were prepared by forming a stable emulsion using a homogenizer and a steric stabilizer, PVP. With this process, MWCNTs can be location-selectively incorporated in PC microspheres to afford the required properties such as electrical conductivity and thermal stability. When MWCNTs were dispersed in an aqueous phase using PVP, they were incorporated only on the surface of the PC microspheres. However, PC microspheres incorporating MWCNTs inside them were fabricated when the MWCNTs were dispersed in methylene chloride by functionalizing them via alkylation. (C) 2008 Elsevier Ltd. All rights reserved.