Abstract
Films containing up to 54-60 vol % CdS nanoparticles were prepared through in situ reactions using polymer matrices with a strong [poly(acrylic acid) (PAA)-poly(vinyl acetate) (PVA) mixture] or low complexing ability (cellulose) with respect to transition-metal ions. The effect of the type of polymer matrix on the structure of such nanocompositions was studied. In the synthesis of the above nanocompositions via the repeated treatment method, the development of disperse phase particles involves the appearance of primary particles in the polymer matrix and their further coagulation and formation of secondary particles. As compared with cellulose, the PAA-PVA matrix can stabilize much smaller CdS particles (with increasing the degree of filling,. the dimensions of primary particles increase from 4.6 to 13 nm for the PAA-PVA system and from 8 to 24 nm for cellulose; the dimensions of secondary particles are equal to 50-60 and 70-80 nm, respectively). As the concentration of Na2S in the reaction medium is increased, the dimensions of CdS particles also increase. The stabilized size of disperse phase particles is controlled by the specific interfacial free surface energy gamma(1.2) of a nanocomposition; this energy decreases with increasing the complexing ability of the polymer matrix or with decreasing the concentration of Na2S. With decreasing gamma(1.2), the level of dispersion of the as-formed nanocompositions is shown to increase.