Synthesis and characterization of poly(N-isopropylmethacrylamide) microgels and their applications in nanotechnology and catalysis Robina Begum, Rashida Mukhtar School of Chemistry, University of the Punjab, Pakistan Smart polymer microgels have gained much consideration in last decade because of their potential uses in nanotechnology and catalysis. 1-3 In present work, poly(N-isopropylmethacrylamide) microgel particles were synthesized via free radical precipitation polymerization in aqueous medium. Aqueous dispersion of the polymer microgel particles was used as micro-reactor for in-situ reduction of silver ions with sodium borohydride to produce silver nanoparticles loaded hybrid microgels. Synthesized poly(N-isopropylmethacrylamide) microgels and Ag-poly(N-isopropylmethacrylamide) hybrid microgels were characterized using various techniques such as UV-Visible spectroscopy, Fourier transform infrared (FTIR) spectroscopy and transmission electron microscopy (TEM). Spectrophotometric monitoring of silver nanoparticles loaded into the microgels reveals that they are highly stable within polymeric network and their optical properties can be tuned by changing the temperature of the medium. The catalytic activity of the hybrid microgel system was evaluated by reducing 4-nitrophenol with sodium borohydride in aqueous medium. The reduction of 4-nitrophenol was carried out under different conditions of concentration of NaBH 4 , 4-nitrophenol and catalyst to explore the process of catalysis. 4-nitrophenol was successfully converted into 4-aminophenol in the presence of the hybrid microgel system. Catalytic system can be recovered by simple centrifugation and re-used without any significant loss of activity. References 1. Tahir, R. Begum, W. Wu, A. Irfan and Z. H. Farooqi, RSC Adv., 2021, 11 , 978-995. 2. Begum, Z. H. Farooqi, E. Ahmed, A. Sharif, W. Wu, and A. Irfan, RSC Adv., 2019, 9 , 13838-13854. 3. Tzounis, M. DonĚ a, J. M. Lopez-Romero, A. Fery, and R, Contreras-Caceres, ACS Appl. Mater. Interfaces , 2019, 11 , 29360- 29372.
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