Simple method of hybrid PVD/PECVD to prepare well-dispersed cobalt–plasma polymerized hexamethyldisilazane nanocomposites

Abstract

A simple and easy method to prepare well-dispersed cobalt–plasma polymerized hexamethyldisilazane (Co–pp HMDSN) nanocomposites is presented. A hybrid physical vapor deposition (PVD) and plasma enhanced chemical vapor deposition (PECVD) technique was used to prepare finely dispersed Co–pp HMDSN nanocomposites. The metal filling factor could be varied from 4% to 34%. Structural investigations were performed using transmission electron microscopy (TEM) and X-ray diffractometry (XRD). They revealed the presence of amorphous cobalt nanoparticles of size ~2–3nm at lower filling factor, whereas crystalline CoO nanoparticles of size ~6nm were observed at higher filling factor. Energy dispersive X-ray spectroscopy (EDX) and profilometry were employed to determine the filling factor. Compositional analysis using Fourier transform infrared (FTIR) spectroscopy indicated the presence of SiO and SiC bonds in the polymer matrix. The influence of oxygen was observed in all nanocomposites. With the increase in filling factor the polymer matrix was significantly modified. A set of well-dispersed Co–pp HMDSN nanocomposites with varying metal filling factors was prepared which is suitable as precursor for calcination. As the functional properties of the calcinated nanocomposites are dependent on the properties of the precursors, the importance of a detailed study of the precursors for calcination is emphasized. A simple and generalized procedure to introduce well-dispersed metal nanoparticles into a polymer matrix is demonstrated.