Effect of ultrasonic treatment on electromagnetic properties of composites based on multiwall carbon nanotubes at microwave frequency range

Abstract

Nanostructured composite materials have opened a new era for multifunctional materials (such as reflection, absorbing, conducting etc.). In particular, multiwalled carbon nanotubes (MWCNTs) can be applied in order to improve electromagnetic properties in composites. Polymer composite materials based on MWCNTs were obtained. In this paper, microwave properties of polymer composites based on MWCNTs have been analyzed. Frequency dependences of permittivity of MWCNTs/varnish composite films were investigated in the range 3-14 GHz. The multiwall carbon nanotubes used in the composite were about 9.4 nm and 18.4 nm in diameter. The results show that the ultrasonic treatment modifies the dielectric permittivity of the composite. The dependence of the real and imaginary parts of the permittivity of sonication time is non linear.