Novel Processing to Produce Polymer/Ceramic Nanocomposites by Atomic Layer Deposition

An innovative process to uniformly incorporate dispersed nano-scale ceramic inclusions within a polymer matrix was demon-strated. Micron-sized high density polyethylene particles were coated with ultrathin alumina films by atomic layer deposition in a fluidized bed reactor at 77°C. The deposition of alumina on the polymer particle surface was confirmed by Fourier transform infrared spectroscopy and X-ray photoelectron spectroscopy. Conformal coatings of alumina were confirmed by transmission electron microscopy and focused ion beam cross-sectional scan-ning electron microscopy. The results of inductively coupled plasma atomic emission spectroscopy suggested that there was a nucleation period. The results of scanning electron microscopy, particle size distribution, and surface area of the uncoated and nanocoated particles showed that there was no aggregation of particles during the coating process. The coated polymer parti-cles were extruded by a heated extruder at controlled temperα-tures. The successful dispersion of the crushed alumina shells in the polymer matrix following extrusion was confirmed using cross-sectional transmission electron microscopy. The dispersion of alumina flakes can be controlled by varying the polymer par-ticle size.