Stability and mechanical properties of polyelectrolyte capsules obtained by stepwise assembly of poly(styrenesulfonate sodium salt) and poly(diallyldimethyl ammonium) chloride onto melamine resin particles

Capsules composed of poly(styrene sulfonate, sodium salt) (PSS)/poly(dially ldimethyl ammonium) chloride (PDADMAC) were prepared by layer-by-layer depo sition of the polyelectrolytes on melamine formaldehyde colloidal templates followed by the decomposition of the cores by hydrochloride. A yield of mo re than 90% of intact capsules was achieved if (i) the core diameter was eq ual to or less than 3.8 mum and (ii) not more than five pairs of layers wer e adsorbed. When the cores were larger or the layers were thieber, the osmo tic pressure difference caused by core dissolution led to an increased freq uency of wall rupture. The elasticity modulus of a multilayer consisting of five pairs of PSS/PDADMAC was about 140 MPa as measured by osmotic pressur e induced capsule deformation.