Microwave‐Assisted <i>N</i> ‐Isopropylacrylamide Nanogel Synthesis: Exploring the Role of Reaction Parameters and Cross‐linking Agents

This study provides a detailed account of the use of microwave-assisted synthesis as a novel and efficient method for preparing monodisperse poly(N-isopropylacrylamide) (PNIPAM) nanogels. The synthesis, based on free radical precipitation copolymerization of NIPAM and crosslinkers in water, was accelerated by microwave irradiation. Crosslinkers such as ethylene glycol dimethacrylate (EGDMA) and degradable bis-acryloylcystamine (BAC) were employed to study their effects on nanogel structure and properties, including their temperature-responsive behavior. HPLC analysis revealed differences in monomer and crosslinker conversion between the two agents. The growth of the nanogel particles was analyzed at various polymerization times using dynamic light scattering (DLS), ζ-potential measurements, and cryo-TEM imaging. The data showed that microwave-assisted synthesis reduced reaction time from 6 hours to minutes. BAC produced uniformly cross-linked nanogels, whereas EGDMA formed nanogels with dense cores and loose PNIPAM shells. Stability studies during storage and in biologically relevant media indicated their potential for biomedical applications.