Nanocomposite films containing Au nanoparticles embedded in a
polymer matrix were prepared by vapour phase co-deposition of Au and
polymers (Teflon AF and Poly($\alpha $-methylstyrene)) in high vacuum. The
microstructure of the composite materials as well as metal content strongly
depend on the condensation coefficient of the Au atoms, the deposition rates
of the components, the substrate temperature, and the type of polymer
matrix. The condensation coefficient, which varies between 0.03 and 1, was
determined from energy dispersive X-ray spectrometer (EDX) and surface
profilometry. It is shown that the microstructure of nanocomposites (size,
size distribution, and interparticle separation of metal clusters), which
was determined by transmission electron microscopy, can be controlled by the
deposition parameters and the choice of polymer matrix. The optical
absorption in the visible region due to the particle plasmon resonance has a
strong dependence on the metal filling factor. The correlation between the
microstructure of nanocomposites and optical properties, studied using
UV-Vis spectroscopy, was also established. Further more, the electrical
properties of the composites were studied as a function of the metal volume
fraction. It was observed that the nanocomposite films exhibit a percolation
threshold at a metal volume fraction of 0.43 and 0.20 for gold nanoclusters
in Teflon AF and Poly(α-methylstyrene), respectively.