Polyacrylates in the presence of an extraordinary monovalent cation—Solution behavior and metal nanoparticle formation

Abstract

Sodium polyacrylate (NaPA) in dilute aqueous solution at an ionic strength of [NaNO3] = 0.01M establishes a rich phase behavior in the presence of low amounts of silver cations, which were introduced at a few millimoles or less by replacing the corresponding amount of Na+ cations. Beyond an extremely low level of Ag+ cations, anionic PA chains aggregate. By increasing the concentration of Ag+, the aggregates become denser and keep on growing without limit. Once a certain range of [Ag+] is reached, the instantaneously formed dense aggregates remain stable. Irradiation of the PA aggregate solutions with UV-light induces formation of silver nanoparticles (Ag-Nps). Based on a combination of UV-vis spectroscopy, light scattering, transmission electron microscopy, and small angle neutron scattering, the mechanism of this NaPA assisted formation of Ag-Nps is studied. One focus of the study is lying on the effect of the two different solution states of dense aggregates, corresponding to the unstable growing AgPA aggregates and to the stable AgPA aggregates and another focus is aiming at the characterisation of the morphology of the generated hybrid particles composed of Ag-Nps and hosting PA chains.

Synthesis of silver nanoparticles by sonogalvanic replacement on aluminium powder in sodium polyacrylate solutions

“…3 ) and at pH ≥ 10 is in the anionic form only [33] . Ag + ions are bonded with the anionic form (COO – ) with the formation of soluble complexes [28] , [29] , which can be written as [Ag m PA] (n–m)– . With the use of the anionic form, the formation of the surface complexes with AgNPs is also carried out, i. e. the stabilization of the latter takes place.…”

“… [26] , [27] , [28] the possibility of complex bond formation between the functional group COO − of polymer anion PA – and the Ag + ions is considered. PA – anions also form the surface complexes with AgNPs with the formation of a peculiar nanostructure of Ag@PA, which provides an effective stabilization of nanoparticles [26] , [27] , [28] , [29] , [30] , [31] , [32] . Sodium polyacrylate is also a non-toxic and relatively cheap and widely available surfactant.…”

Microplasma Synthesis of Antibacterial Active Silver Nanoparticles in Sodium Polyacrylate Solutions

“…The fraction of the anionic form increases with an increase in the concentration of ОН − ions [ 52 ]. In sodium polyacrylate solutions, Ag + cations form soluble [Ag m PА] (n-m)- complexes [ 50 , 51 , 53 ]. The latter are transformed into stabilized nanoclusters and nanoparticles ( 9 ) during microplasma glow discharge due to the reduction of Ag (I) to Ag (0) by hydrated electrons and generated radicals and compounds.…”

“…e aim of the work is to study the regularities of microplasma synthesis of silver nanoparticles in sodium polyacrylate solutions and establish the conditions of their stable formation. Polyacrylate is a nontoxic synthetic polymeric anionic surfactant that is known to be an effective stabilizer for MNPs [50][51][52][53][54][55][56].…”

Dilute polyelectrolyte solutions: recent progress and open questions

“…L-Type precipitation, while usually associated with divalent and higher-valent ions, 201,225 is also observed for monovalent ions with high coordination numbers notably Ag + . 226,227 The critical added alkaline earth concentration c ÃÃ s À Á to precipitate 90% neutralised polymethacrylic acid (PMA) is plotted in Fig. 5(a).…”