Abstract:

In order to study the sustained release of water-soluble substances or dyes from microcapsules, polystyrene sulfonate (PSS) was choose to adjust the growth of calcium carbonate (CaCO3) particles. Poly(allyamine hydrochloride) (PAH) and PSS were assembled on the template surface, and ethylenediamine tetraacetic acid (EDTA) was used to remove CaCO3 particles, then hollow polyelectrolyte microcapsules were obtained. The water-soluble Rhodamine B (RhB) embedded into the microcapsules. The effect of layers, pH and salt concentration on release behavior of RhB from microcapsules were studied. The results showed that: there was a similar release behavior of encapsulated RhB at different pH, while the release rate and amount at acidic conditions were greater than the neutral and alkaline conditions; the permeability was decreased with increasing the number of layers, the largest release amount occurred when assembled seven layers; salt concentration less than 0.05 mol/L was better for improving the release rate, and increasing the concentration would reduce the rate.

Key words: polyelectrolyte microcapsule, layer by layer assembly, dyes, controlled release