Controllably layer-by-layer self-assembled polyelectrolytes/nanoparticle blend hollow capsules and their unique properties

Fabrication of a polymer/nanoparticle composite capsule with controllable nanoparticle properties remains a great challenge in material science. In this work, a three-component layer-by-layer (LbL) self-assembly process using a weak polyelectrolyte-nanoparticle blend and another weak polyelectrolyte was systematically studied to fabricate the composite capsules. The pH of the assembled polyelectrolyte and blend ratio of polyelectrolyte to nanoparticle were used to controllably construct blend multilayers on colloidal templates without aggregation. The capsules were then produced by removal of the templates and possess well-dispersed assembled nanoparticles with desired concentration, size and interparticle spacing for large tunability of localized surface plasmon resonance (LSPR) and ultrahigh permeability, which have not been accomplished by the reported polyelectrolyte or polyelectrolyte/nanoparticle capsules. This work also investigated the fundamental insights of the blend LbL self-assembly process while providing a universal approach to fabricate well-dispersed microcapsules with desired nanoparticle properties for various applications such as intelligent drug delivery, biosensing and bioimaging applications.