The electrorheological effect and dielectric properties of suspensions containing polyaniline@titania nanocable-like particles

Abstract

The core/shell structured particle is one of the most promising electrorheological materials. In this paper, we prepared two kinds of core/sheath structured polyaniline@titania nanocable-like particles with conducting cores and non-conducting cores for use as new nanofiber-based ER fluids. The morphology and structure of the nanocables were characterized by scanning electron microscopy, transmission electron microscopy, line profiles of element content, and Fourier transform infrared spectra. Under DC electric fields, the ER effect of the unique cable-like nano-architectures dispersed in electrically insulating oil was examined and compared by steady shear flow and dynamic oscillatory shear modes. It was found that the two nanocable suspensions showed distinctly different ER responses, which depended on the conductivity of the core. The suspension containing nanocables with a conducting polyaniline core exhibited high static yield stress but unstable flow curves and abrupt rupture behavior when the stress was beyond the yield point, while the suspension containing nanocables with a non-conducting polyaniline core exhibited stable flow curves and gradual rupture behavior. The dielectric spectra measurements indicated that there was a significant difference in the polarization response between the two nanocable suspensions, which could produce the different rheological properties.