Synthesis, structure, and properties of metal-polymer nanocomposites basedon silver and poly-p-xylylene

Through simultaneous vapor deposition of a reactive monomer and inorganic s ubstances, followed by solid-state synthesis of the polymer poly-p-xylylene , nanocomposites were prepared with a controllable high concentration of si lver nanoparticles organized in the polymeric matrix. A wide-angle X-ray di ffraction study on the structure of the nanocomposites obtained showed the presence of silver clusters 10-12 nm in size localized in amorphous regions of poly-p-xylylene. Samples containing 2 vol. % metal exhibit hopping (tun neling) conductivity. Above the percolation threshold (at 7 vol. % silver), the conductivity changes to the metal type. The nanocomposites possessing the hopping conductivity display sensor properties toward moisture (the res istance decreases by an order of magnitude as the relative humidity of a sy stem varies from 75 to 100%).