Effective medium theory of the microwave and the infrared properties of composites with carbon nanotube inclusions

Carbon nanotubes (CNs) are electrically small particles at infrared and mic rowave frequencies. The Mossotti-Clausius formalism for estimating the effe ctive permittivity dyadic of a dilute composite containing CN inclusions is described, and simplifications for certain orientational statistics are di scussed. The polarizability dyadic of an electrically small CN is estimated from that of an infinitely long CN of the same cross-sectional diameter. A collection of randomly dispersed, aligned, nonchiral, electrically small C Ns is shown to be transparent in the axial direction, but it can be either opaque or transparent in the transverse plane. Its effective electromagneti c response properties can be manipulated by a biasing magnetic field. (C) 1 998 Elsevier Science Ltd. All rights reserved.