MWCNTs/SiO₂ composite system: Carrier transmission, twin-percolation and dielectric properties

We synthesize composite systems of multi-wall carbon nanotubes (MWCNTs)/SiO₂ by using the sol-gel method. The dielectric properties of the systems with different-concentration MWCNTs are studied. In our MWCNTs/SiO₂ inorganic systems, the twin-percolation phenomenon exists when the concentrations of MWCNTs are 5-10% and 15-20%. The permittivity and conductivity have jumping changes. The twin-percolation phenomenon is attributed to the special transfer mechanism of MWCNTs in the system, determined by hopping and migrating electrons. Variations of dielectric properties and conductance of the MWCNTs/SiO₂ systems are conformed to the percolation theory. The special percolation phenomenon and electric properties of MWCNTs/SiO₂ can help us comprehend the conductivity mechanism of the MWCNTs/SiO₂ systems effectively, and promote the development of a high performance function composite system.