In Situ Formation of Ag Nanoparticles in Spherical Polyacrylic Acid Brushes by UV Irradiation

Abstract

We reported on the in situ synthesis of silver nanoparticles onto polystyrene (PS) core−poly(acrylic acid) (PAA) polyelectrolyte brush particles. The synthesis of these composite particles proceeds through a photoemulsion polymerization in aqueous dispersion using the functional monomer silver acrylate. In this way the layer of the chains of poly(acrylic acid) on the surface and the Ag nanoparticles are formed at the same time. Dynamic light-scattering (DLS) measurement demonstrates the formation of polyelectrolyte brushes onto the PS core surface. TEM and cryo-TEM images show that well-dispersed Ag nanoparticles (d = 3 ± 1.2 nm) are formed in situ on the surface of PS−PAA spherical polyelectrolyte brush particles. Moreover, wide-angle X-ray scattering indicates that Ag nanoparticles formed in the brushes are crystalline. The catalytic activity is investigated by monitoring the reduction of 4-nitrophenol by NaBH4 in presence of these silver nanocomposite particles. The rate constant k app of this reaction was found to be slightly smaller than the one of Pd or Pt nanoparticles immobilized on carrier particles of the same type. All data demonstrate that the present way of synthesis leads to extremely small Ag particles immobilized on a stable carrier.

Effect of acrylic acid feed contents of microgels on catalytic activity of silver nanoparticles fabricated hybrid microgels

“…Therefore, microgels are considered to be ideal for the synthesis of particles having nano dimensions. 44 The p(NIPAM-co-AAc) microgels are co-polymers of NIPAM and AAc. AAc is an acidic monomer that ionizes when the pH of the medium is greater than its pK a value ( ∼ 4.25).…”

Voltammetric and impedimetric behaviour of phytosynthesized nickel nanoparticles

“…However, some chemical methods cannot avoid the use of toxic chemicals in the synthesis protocol; for instance, hazardous substances such as tetrakis hydroxymethyl phosphonium chloride (THPC) [1], poly-N-vinyl pyrrolidone (PVP) [2] and hydroxylamine [3] were used for the synthesis of metal nanoparticles in the traditional wet methods. Other dry methods such as UV-irradiation [4] aerosol [5] and lithography [6] are also not considered environmentally friendly. The presence of these toxic chemicals on the surface of nanoparticles limits their medical applications.…”

Toxicity and antibacterial assessment of chitosan-coated silver nanoparticles on human pathogens and macrophage cells

“…12 To date, numerous methods concerning the fabrication of AgNPs have been developed. [13][14][15][16] Among the synthetic methods, a chemical reduction of silver salt solution using reducing agents such as sodium dodecyl sulfate, citrate, ascorbate, hyperbranched polyester, N,N-dimethylformamide, and sodium borohydride is most commonly used. [16][17][18] Most of these reducing agents lead to environmental toxicity or biological hazards; therefore, the trend has shifted to biological synthesis of AgNPs using polymer matrices, as they have no toxicity risks and they can be easily designed into almost any shape required for a particular application.…”