Poly(N,N-dimethylacrylamide)-based microspheres prepared by heterogeneous polymerizations

PDMAAm microspheres have been obtained by inverse suspension, inverse emulsion, and dispersion polymerization. Concentional inverse suspension polymerization in toluene/tri-chloroethene is modified by the use of ultrasound. The resulting hydrogel microspheres are examined by dynamic light scattering and scanning electron microscopy to afford the morphology, dispersity, and size of the microspheres. Inverse suspension polymerization yield 100-mu m particles, while those obtained by inverse emulsion polymerization are 0.13-1 mu m in diameter. While the inverse techniques produce particles of broad size distribution, mono-disperse microspheres are obtained by the Kraton G 1650-stabilized dispersion polymerizationo of DMAAm in a toluence/heptand medium. The particle size and polydispersity could be controlled by the addition of water into the dispersed phase, and by varying the cellulose acetate butyrate or Kraton G 1650 concentration and the toluene/trochloroethene of toluene/heptane ratio.