STUDY OF AG+/PAA (POLYACRYLIC-ACID) AND AG0/PAA AQUEOUS SYSTEMS AT EQUILIBRIUM

When submitted to gamma radiation the system Ag+-PAA-water leads to clusters Ag0n/PAA (3 less-than-or-similar-to n less-than-or-similar-to 8) the UV spectrum of which at lambda less-than-or-similar-to 380 nm is accompanied by a visible band depending on the PAA ligand (lambda greater-than-or-similar-to 420 nm) interacting with the clusters. Potentiometric measurements carried out on Ag+ solutions in the presence of PAA at various pH show that the deprotonated form (polyacrylate anion) is strongly bonded to Ag+, on the opposite of the protonated form of PAA. One of the oligomer clusters can be stabilized for more than one year. Studying it by infra-red spectrometry reveals important modifications in the vibration bands of the COO- group circa 1400 and 1600 cm-1 according to the bonding of PAA with Ag+ or Ag0.