Kinetic study on the copper electroless coating on carbon nanotubes

The present work deals with the kinetics of Cu coating on carbon nanotube by electroless deposition method performed at five temperatures of 10, 25, 50, 75 and 90 degrees C. A theoretical model for nucleation and growth transformation based on Johnson-Mehl-Avrami equation was applied for determining the kinetics and mechanism of the process. The evolution of the Cu precipitation was assessed by the variation of Cu2+ ion concentrations in the electroless bath solution. The average Avrami exponent was acquired 1.35 which is in agreement with the grain boundary nucleation after saturation with interface controlled growth mode. It was found that raising the temperature of the solution could accelerate the reaction rate. The value of 49.9 kJ mol(-1) obtained for the activation energy is of the same order as found in similar surface chemical-controlled processes. The X-ray diffraction result revealed that the crystalline structure of Cu was obtained on CNTs from the electroless process. Field emission scanning electron microscopy results were in agreement with the trends of nucleation and growth mechanism and showed that the CNTs were uniformly covered with Cu after the process. Fourier transform infrared spectroscopy test demonstrated that the functional groups formed by functionalizafion treatment on the surface of CNTs might act as suitable nucleation sites.