in a few microencapsulation processes, the direct polymerization of a single monomer is carried out on the particle surface. in one process, e.g. cellulose fibers are encapsulated in polyethylene while immersed in dry toluene. usual deposition rates are about 0.5μm/min. coating thickness ranges . the coating is uniform, even over sharp projections. protein microcapsules are biocompatible and biodegradable, and the presence of the protein backbone renders the membrane more resistant and elastic than those obtained by interfacial polycondensation.