Stimuli‐Responsive Multilayered Hybrid Nanoparticle/Polyelectrolyte Capsules

Abstract

Abstract Gold nanoparticles (Au NP ) with carboxyl groups on their surface were used in combination with PAH for the layer‐by‐layer coating of CaCO 3 microparticles, followed by the dissolution of the CaCO 3 core. SEM, TEM, and confocal microscopy are used to characterize the hybrid nanoparticles/polyelectrolyte capsules. As the Au NP have carboxyl groups on their surface, their charge density is pH dependent; therefore, the capsules exhibit a pH‐dependent swelling and can be deconstructed both at low and high pH. By covalent cross‐linking of the carboxyl groups of the Au NP and the amino groups of the PAH, it is possible to suppress the pH‐responsive behavior. Au NP are used as activation centers using IR light and this ability is used to release encapsulated material from the nanoparticles/polyelectrolyte capsules as well as for the enhancement of detection and imaging of such capsules by Raman microspectrosopy. magnified image