Preparation of micro-scaled multilayer capsules of poly-dimethyl-diallyl-ammonium chloride and sodium cellulose sulfate by layer-by-layer self-assembly technique

Novel homogeneous micro-scaled hollow polyelectrolyte capsules were prepared by using alternate adsorption of poly-dimethyl-diallyl-ammonium chloride (PDMDAAC) and cellulose sulfate sodium (NaCS) on calcium carbonate (CaCO3) template particles. The CaCO3 particles with various shapes were prepared by the reaction of potassium carbonate (K2CO3) with calcium chloride (CaCl2) in the presence of carboxylmethyl cellulose (CMC). The results showed that at a CMC concentration of 0.5 g/L, smooth spherical CaCO3 particles were obtained, which were used as core templates. Thereafter four bilayers of PDMDAAC and NaCS polymer film were deposited on the CaCO3 cores. The film buildup was characterized by (i) microelectrophoresis; (ii) scanning electron microscopy (SEM); and (iii) thermogravimetric analysis (TGA). Hollow capsules were then prepared by exposing the coated CaCO3 particles to EDTA-Na. Finally the molecular weight cut-off (MWCO) of the microcapsules was determined by exposing the microcapsules to the E. coli cell lysate.