Electrically Conducting Polymeric Microspheres Prepared by Adsorption of Multiwalled Carbon Nanotubes

Abstract

Multiwalled carbon nanotubes (MWCNTs) were incorporated onto the surface of polystyrene (PS) microspheres by a simple and potentially scalable process. PS microspheres, 3.0 μm in diameter, were prepared using a dispersion polymerization method. These were adopted as the suspended particles for electrorheological (ER) fluids, in which the electrical conductivity was mainly derived from the conducting MWCNTs layers coated on the surface of the microspheres. The MWCNT/PS composite suspensions in silicone oil showed the typical characteristics of an ER fluid, forming a chain-like structure under an applied electric field (0.8 kV/mm). The MWCNTs/PS composite microspheres exhibited a conductivity of about 2.0 × 10⁻⁴ S/cm, which is in the typical range for ER fluids. This phenomenon can be explained by the interfacial polarizability of the MWCNTs adsorbed on the surface of the polymeric microspheres.

Keywords:

• electrical conductivity
• electrorheological fluids
• microspheres
• multiwalled carbon nanotubes
• polystyrene

Acknowledgments

The authors of this paper would like to thank the Korea Science and Engineering Foundation (KOSEF) for sponsoring this research through the SRC/ERC Program of MOST/KOSEF (R11–2005–065).