Radiolytic synthesis polymers

Actually, the kinetics study of the redox potential of transient clusters (Section 20.3.2) has shown that beyond the critical nuclearity, they receive electrons without delay from an electron donor already present. The critical nuclearity depends on the donor potential and then the autocatalytic growth does not stop until the metal ions or the electron donor are not exhausted (Fig. 8c). An extreme case of the size development occurs, despite the presence of the polymer, when the nucleation induced by radiolytic reduction is followed by a chemical reduction. The donor D does not create new nuclei but allows the supercritical clusters to develop. This process may be used to select the cluster final size by the choice of the radiolytic/chemical reduction ratio. But it also occurs spontaneously any time when even a mild reducing agent is present during the radiolytic synthesis. The specificity of this method is to combine the ion reduction successively ... 

Krkljes, A. N., Marinovic-Cincovic, M. T., Zorica, M., Kacarevic-Popovic, Z. M., and J. M. Nedeljkovic. 2007. Radiolytic synthesis and characterization of Ag-PVA nanocomposites. European Polymer Journal 43 2171-2176. 

The final size ofthe clusters depends on the metal it decreases as the initial polymer/ ion concentration ratio increases and with PVA lies in the nanometre range (1-10 nm).The radiolytic method has been used for the synthesis ofa great number of noble and non noble metal nanocolloids in various solvents, water, alcohols, liquid ammonia, etc. Their intense colours, due to a Mie resonance in light absorption by the electron pool of the particle, depend on the surrounding medium, on the cluster size and shape, and on the metal (Fig. 4) in water, yellow for Ag spheres of a few nm 380 nm), purple for Au ( max=520nm),... 

In an interesting example of radiolytic colloid synthesis, both the colloidal metal and the polymer are produced simultaneously by radiolysis of the solutions of a metal salt and a monomer. Radiolysis of aqueous solutions of H2PtO containing either acrylamide or A/-methylolacrylamide with a CO y-radiation source yielded highly dispersed colloidal platinum (diameter 1.7 nm). [104]... 

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