Plasma Polymer Matrix Research Articles

Plasma polymer thin films with encapsulated dye molecules and silver nanoparticles

Plasma polymer thin films with encapsulated dye molecules (rhodamine 6G) and silver nanoparticles were deposited by alternating plasma polymerization, dye sublimation and metal evaporation. The interference between the optical absorption of the plasma polymer, the dye molecule absorption and the plasma resonance absorption of the silver particles was measured in the UV-visible-near-IR spectral region. Fluorescence measurements demonstrate plasma polymer matrix effects on fluorescence of the dye molecules.

Electron beam induced coalescence in plasma polymer silver composite films

Plasma polymer thin films with embedded silver particles (5-50 nm) were irradiated by a small focussed electron beam of 10 kV. Before and after irradiation the films were investigated by transmission electron microscopy (TEM) to characterize the microstructure given by size and shape of the embedded silver particles. The changes of the microstructure after the electron beam irradiation were limited to small lines (<2 μm). Most changes were coalescence of the silver particles. Furthermore, after increased irradiation time and higher energy input areas nearly free of silver particles but without destruction of the plasma polymer matrix were found.

Size dependence of the lattice parameter of small palladium particles

Small palladium particles with mean diameters ranging from 1.4 to 5 nm have been prepared within a plasma polymer matrix from a vinyltrimethylsilane monomer. Electron diffraction has shown a decrease of the Pd lattice parameter with decreasing size of palladium cluster. These experimental data are used to deduce the value of the surface stress coefficient f=6.0\ifmmode\pm\else\textpm\fi{}0.9 N/m. A contraction of the lattice constant of small palladium particles with decreasing of cluster size, to our best knowledge, has not been reported in the literature up to now. The results suggest that the dilatation of the Pd lattice constant, often reported in the literature, can be explained in terms of incorporation of impurities like carbon, hydrogen, and oxygen, or pseudomorphism in the case of crystalline supports.

Laser annealing and surface modification of plasma polymer-metal composite films

Plasma polymer films with encapsulated metal particles were prepared by simultaneous plasma polymerization and metal evaporation. Laser annealing (Nd-YAG, 1064 nm) causes dramatic changes in the particle size and shape without material ablation, but with changes in the surface topography. This results in changes in the optical plasma resonance absorption, as demonstrated by UV-visible-near-infrared (NIR) spectroscopy. The invariable transmission in the UV region of the plasma polymer matrix after laser annealing confirms that there is no material ablation. Transmission electron microscopy (TEM) and scanning electron microscopy (SEM) demonstrated particle size changes and modifications of the plasma polymer surface due to laser annealing.

TEM-cross section investigations of plasma polymer silver composite films

Plasma polymer silver composite films were investigated by means of cross section transmission electron microscopy (XTEM). The silver is encapsulated in the form of small particles in a nearly homogeneous plasma polymer matrix. The shape and the size of the particles vary with the polymerization power density. At lower polymerization power density the silver particles appear almost spherical and a three-dimensional particle distribution can be found in the polymer matrix. However the shape of particles at higher power density is more elliptic and the particle distribution is two-dimensional. The different kinds of encapsulation can be interpreted as being due to the different densities and porosities of the plasma polymer matrix.