METAL-CLUSTERS IN PLASMA POLYMER MATRICES - COLD CLUSTERS

By means of an inert gas evaporation technique in combination with a s imultaneous plasma polymerization process, gold clusters with mean dia meters ranging from 1.4 to 5 nm have been prepared within plasma polym er matrices from vinyltrimethylsilane and tetraethoxysilane monomers. For the characterization of these materials high-resolution electron m icroscopy (HRTEM), electron diffraction (ED), X-ray photoelectron spec troscopy (XPS), Fourier transform infrared (FTIR) spectroscopy, and W- vis spectrophotometry were used. Electron diffraction has shown a decr ease of the Au lattice parameter with decreasing size of the gold clus ter. The experimental data were used to deduce the value of the surfac e stress coefficient f = 6.3 +/- 1 N/m. W-vis spectrophotometry reveal ed a strong blue shift of the plasmon resonance frequency from lambda = 578 nm (D-Au = 5 nm) to lambda = 532 nm (D-Au = 2 nm), In the case o f the 1.4 nm clusters, a distinct absorption peak could not be observe d. In the case of the plasma polymer matrix from a tetraethoxysilane m onomer, a strong chemical damping of the surface plasmon resonance has been observed.