Enhanced microwave absorption performance of polyaniline-coated CNT hybrids by plasma-induced graft polymerization

Highly conducting CNT/polyaniline hybrids were prepared by plasma-induced graft polymerization, i.e., plasma pretreatment of CNTs and further in situ polymerization of aniline. Plasma pretreatment made more aniline grafted on the CNTs’ surface by the role of oxygen radicals. SEM images showed that the surfaces of CNTs were uniformly coated by PANI. FTIR showed that there was presence of strong interaction between CNTs and PANI molecular chains. The conductivity of CNT/PANI hybrids with plasma treatment is higher than that of CNT/PANI hybrids without plasma pretreatment (0.443 S/cm at 0 W) or pretreated by acid oxidation method. Importantly, the microwave absorption properties were investigated by measuring complex permeability, complex permittivity and reflection loss in a frequency of 2–18 GHz. The microwave absorption enhancement of CNT/PANI hybrids results mainly from dielectric loss rather than magnetic loss due to higher value of dielectric loss.