3-Dimensional stable polyelectrolyte hollow capsules: preparation and spontaneous encapsulation

In this study, by alternatively depositing a poly(styrene)-co-poly(acrylic acid)/poly(allylamine hydrochloride) multilayer on the poly(styrene sulfonate sodium) hybrid CaCO3 spherical templates, a series of size-controlled and low-dispersed polyelectrolyte capsules were obtained after the removal of hybrid templates. These polyelectrolyte capsules can retain their 3-dimensional spheric shape after being dried at room temperature. Through investigating the structure and key factors for the formation of novel capsules, formation mechanism of the 3-dimensional stable capsule wall was discussed. Further investigation showed that the dry capsules could spontaneously entrap water-soluble positively charged substances from the bulk solution into the capsule interior, just like the wet capsules.