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Cluster Structure of the Surface of Plasticized Cellulose Triacetate Films

“…Surface activation yields molecular complexes of bromine with electron-donating functional groups of the CTA macromolecules, the so-called [chemical labels,] acting as AuBr 3 formation sites in decoration, which are potential nuclei for the decorating gold particles. The chemical activation of the surface was carried out in a 0.5 wt % aqueous solution of bromine for 30 s, which was followed by vacuum sputtering of gold to an effective layer thickness of 0.4 nm [7]. Figure 1 presents the electronic absorption spectra of the CTA film before and after activation with bromine.…”

“…The spatial distribution of the decorating particles is nonuniform; the film surface contains areas with enhanced local density of particles. These areas correspond to the macromolecular clusters [7] between which larger gold particles are formed by the [point] particle coalescence mechanism. The surface of the CTA film containing TPP exhibits nonuniformly distributed extended areas, in which large decorating particles are localized (Fig.…”

“…The topography of the gold particles on the surface of the film samples was studied on an EMV 100L electron microscope at the 0 40 000 magnification and analyzed by the procedure described in [7,10,11]. The area of scanning of the micrographs with 0 150 000 magnification, when processed on a PC, was 232.5 mm 2 .…”

“…The agglomerations of the decorating gold particles on the film surface were represented as lattice clusters [6] on a two-dimensional lattice with the interpoint distance equal to the most probable distance r (see table) separating the particles and with the coordination number m corresponding to the average number of the nearest neighbors around an arbitrarily chosen particle [7]. The micrographs show that there is a single cluster of decorating particles on the film surface, and the topology of this duster corresponds to that of the infinite cluster of the CTA macromolecules.…”

“…Our previous studies [7] suggest that the sites of the physical network of macromolecules in the CTA films obtained from polymer solution are represented by aggregates or clusters of the macromolecules, formed in solution. Such clusters have a fractal nature and exhibit an enhanced density of packing of the macromolecules, compared to the average density of the polymer.…”