Microgel particles are soft polymer hydrogels, in particulate form. These materials are studied as colloidal suspensions, where their physical interactions provide a pathway for developing new biomaterials for biologically related applications, including tissue regeneration and drug delivery. Microgels are micron-sized particles made mostly of water, polymer chains and crosslinks. In this project, microgel particles have been synthesized with different crosslinking densities, which correspond to having different mechanical stiffnesses. In this work, the microgels were synthesized via precipitation co-polymerization from n-isopropylacrylamide (NIPAM) monomer and acrylic acid (AAc) [90/10]. The stiffness was varied by adjusting the addition of N,N’methylenebisacrylamide (BIS) crosslinking agent, ranging between 0 – 2%. Ammonium persulfate was used as the initiator and the solvent used in the synthesis was deionized water. Precipitation polymerization's the ideal technique for creating homogeneous NIPAM microgel particles, and their homogeneity was verified using atomic force microscopy (AFM) and optical microscopy. Finally, FTIR and 1H NMR were used to verify the chemistry of the functional groups present in the polymer microgel particles. The successful synthesis of these microgel particles will allow for our lab to investigate their thermo-reversible behavior, while immobilized to flat substrates, with the future goal of developing these microgels into biosensors.
