Abstract
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•Polymer microgels were fabricated by two step-precipitation polymerization in aqueous medium.•Silver nanoparticles were loaded in outer region of the microgels by in-situ reduction method.•The donor-acceptor interactions are responsible for long term stability of the hybrid system.•The hybrid microgel system has an excellent catalytic potential towards reduction of 4-NP.
Poly(styrene-N‐isopropylmethacrylamide‐methacrylic acid) [P(SNM)CS] colloidal particles were synthesized by two-step precipitation polymerization in aqueous system. Silver ions loaded into P(SNM)CS network were reduced by using NaBH4 as a reductant to obtain the aqueous dispersion of Ag-P(SNM)CS hybrid particles. Various techniques including transmission electron microscopy (TEM), dynamic light scattering (DLS), UV–Visible (UV–Vis), Fourier transform infrared (FTIR) and thermogravimetric analysis (TGA) were used to characterize P(SNM)CS and Ag-P(SNM)CS systems. Silver nanoparticles have excellent stability in P(SNM)CS system even on their storage for months. Reduction of 4-nitrophenol (4Nph) was chosen as an exemplary reaction to examine the catalytic ability of newly synthesized Ag-P(SNM)CS hybrid microgels under different reaction conditions. Reaction progress was inspected by spectrophotometric method. The value of observed rate constant (kobs) was measured as a dependent of contents of Ag-P(SNM)CS, reductant and substrate using pseudo first order kinetic modeling to explore mechanism of catalysis by Ag-P(SNM)CS.