Carbon Nanotubes-adsorbed Polymeric Microspheres

초록

Carbon nanotubes (CNTs) are among the most exciting new materials since their discovery in 1991.1 Many of their outstanding properties can be best exploited by incorporating CNTs into some form of matrix, and the preparation of CNT-containing composite materials is now a rapidly growing research area.2-6 In may cases, these composites use the polymer matrices. Polymer composites reinforced with CNTs are believed to have many potential engineering uses, ranging from battery electrodes and electronic devices to much stronger composites.2-8 Furthermore, its electrorheological (ER) characteristics have recently been reported, in which a suspension polymerized particle of a CNT nanocomposite with poly(methyl methacrylate) (PMMA) was dispersed in silicone oil.9 ER fluids are mainly suspensions of particles with a higher dielectric constant and/or conductivity than that of the suspending medium fluids with a low dielectric constant and a low viscosity. They exhibit a drastic and reversible change in their rheological characteristics as a result of an applied electric field, because the ER particles are attracted to one another to form fibril structures aligned in the direction of the applied electric field.10,11 In this study, surface-conductive microspheres consisting of polystyrene (PS) (3.0 mm) or PMMA (6.5 mm) core and CNTs-adsorbed shell were prepared using a simple process involving the blending of two colloidal solution; an aqueous CNT dispersion with surfactants and an aqueous PS or PMMA microsphere colloid (Fig. 1).12 These were adopted as the suspended particles for ER fluids, in which the electrical conductivity originated primarily from the surface-coated conducting CNT layers.