The process of nickel nanoparticle formation in hydrophilic polymer/inorganic matrices

Abstract

Polymer/inorganic hybrid based on silica sol and grafted polyacrylamide chains (SiO2/PAAm) was obtained by radical graft polymerization of acrylamide “from” unmodified silica surface. Its main parameters: RavSiO2, MvPAAm and N (the number of grafts per inorganic particle) were determined using static light scattering, elemental analysis, DTGA and viscometry. The hybrid was used as effective matrix in synthesis of NiNPs by borohydride reduction of Ni2+-ions in aqueous medium. A special approach to characterizing the kinetics and efficiency of NiNPs formation in pure water and hybrid solutions using UV-Vis spectroscopy was proposed and implemented. Due to this, an increase in the rate of accumulation and yield of NiNPs both in pure water and hybrid solutions with an increase in the Ni-salt concentration was established. In addition, a decrease in this rate with an increase in the concentration of hybrid matrices was found, as well as a slowdown in the reduction reaction in hybrid solutions compared to pure water. It was shown by TEM that the separate structural elements of the NiNPs/hybrid compositions are the swollen “hairy-type” hybrid structures with a size of ∼8.0–49.2 nm containing small (∼1.0–5.4 nm) NiNPs in PAAm “coronas.”