Nanogels of Poly(N-Vinylcaprolactam) Core and Polyethyleneglycol Shell by Surfactant Free Emulsion Polymerization

Polymeric nanogels containing N-vinylcaprolactam (NVCL) and polyethyleneglycol methylether methacrylate (PEGMA) have been prepared by surfactant free emulsion polymerization. The influence of NVCL to PEGMA concentration ratio on the particle size and particle size distribution was studied. PNVCL:PEGMA nanogel particles exhibit thermal responsive properties in water and their transition temperature increases with higher content on PEGMA. It was found that the particle diameter decreased when higher amounts of PEGMA were used in the monomer mixture. The influence of the concentration and type of cross-linker: ethylene glycol dimethacrylate (EGDMA) or 3,9-divinyl-2,4,8,10-tetra-oxaspiro [5.5] undecane (DVA), on polymerization and colloidal characteristics of such temperature sensitive particles was studied. Nanogels, characterized by Fourier Transform Infrared Spectroscopy (FTIR) Differential Scanning Calorimetry (DSC), dynamic and static light scattering (DLS and SLS) and nuclear magnetic resonance spectroscopy (H-1-NMR), showed higher incorporation of PEGMA than in the recipe, higher contraction by heating for bigger nanogels and spherical morphology.