Design of bristle-like TiO2–MWCNT nanotubes to improve the dielectric and interfacial properties of polymer-based composite films

Abstract

TiO₂–MWCNT heterostructure nanotubes have been fabricated via a solvent-thermal method. Energy dispersive spectrometer and X-ray diffraction analysis revealed that the nanotubes are composed of C, Ti and O elements and TiO₂ only contains the tetragonal anatase phase. SEM and TEM results show that most of the TiO₂ bristles are vertically studded on the surface of the MWCNT. Subsequently, TiO₂–MWCNT/polyarylene ether nitrile (PEN) composite films were prepared in order to investigate the effect of TiO₂–MWCNT on the PEN matrix. SEM images exhibit that there is strong interfacial adhesion between the PEN matrix and fillers owing to the special bristle-like structure. Thermal analysis results show that TiO₂–MWCNT/PEN composite films possess excellent thermal properties endowed by the PEN matrix. Besides, the dielectric constant of the composite films increases from 4 to 109 at 100 Hz when the TiO₂–MWCNT loading reaches 8 wt%. Rheology measurements reveal that there is an obvious difference between the rheological percolation threshold and the electrical percolation threshold.