Impedance characteristics and conductivity of CNT/ABS nanocomposites

Electrical impedance characteristics of multi-walled carbon nanotube (MWCNT)/acrylonitril-butadiene-styrene nanocomposite was studied as a function of MWCNT concentration in the frequency range of 10⁰-10⁶ Hz. The nanocomposites were prepared by solution processing and characterized to have good dispersion of the nanofiller within the polymer matrix as observed by the transmission electron microscopy. In the frequency range of 1-10⁴ Hz, the alternating current (ac) conductivity versus frequency plot of the 0.25 wt% MWCNT nanocomposite exhibited a direct current (dc) plateau indicating that there is a segregated network within this nanocomposite. In the low-frequency region, the bode diagram of the real part of impedance and ac conductivity of the nanocomposites filled with 0.25 wt% up to 4 wt% MWCNT showed a frequency independent plateau followed by an increase obeying the universal dynamic response indicating that conduction in this MWCNT concentration range might be due to tunnelling in addition to the direct contact between filler nanoparticles. For nanocomposites filled with at least 7 wt% MWCNT, the ac conductivity was frequency independent over the entire frequency range (up to 10⁶ Hz) revealing that conduction is due to direct contact between nanoparticles.