Ag-loaded thermo-sensitive composite microgels for enhanced catalytic reduction of methylene blue

In this work, we report the synthesis of composite system pNAC, composed of silver nanoparticles embedded in pure thermo-sensitive crosslinked polymer network of poly(N-isopropylacrylamide-co-acrylamide) (pNA), using as a catalyst for the reduction of methylene blue (MB) dye by sodium borohydride (NaBH₄). The pNA was prepared by conventional free radical polymerization technique using sodium dodecyl sulfate as stabilizing agent, followed by in situ reduction of AgNO₃ inside the polymer network by NaBH₄ for the synthesis of composite systems pNACs. The synthesized pNA and pNACs were characterized by FTIR, dynamic light scattering, thermo-gravimetric analysis, scanning electron microscopy and UV–visible spectroscopy techniques. The materials were found sensitive toward temperature change of the medium. The entrapment ability of pNA toward different amounts of AgNO₃ solution was studied, and effect of metal content on particle size of pNACs was analyzed. The pNACs were applied as a catalyst for the reduction of MB in which they exhibit high catalytic activity and reusability toward the reaction.