The Effect of Water Adsorption on Electrical Conductivity and Permittivity of Diamond Nanopowders

Abstract

The frequency dependencies of conductivity, G(f), and permittivity, ϵ(f), in the frequency range 1 Hz–1.6 MHz at different water vapor pressures were measured for hydrophilic and hydrophobic of detonation nanodiamond powders (∼300 m2/g). It was shown that a sharp increase of G (percolation threshold) was observed at p/ps = 30% for hydrophilic and 60% for hydrophobic samples. The G value changed from 10−12 to 10−5 Ohm−1·cm−1 at relative humidity range from 0% to 95%. The obtained conductivity data were analyzed using the information on quantity water adsorption within the framework of percolation theory and primary adsorption centers of nanodiamond surfaces. It was determined that in low frequency range f < 100 Hz at different water pressure permittivity ϵ has giant value 103–106 associated with surface polarization processes in studied heterogeneous system.