Polyelectrolyte-modified kaolinite nanocontainers for entrapment of corrosion inhibitor benzotriazole

Kaolinite nanoparticles are encapsulated with polymers for application as nanocontainers (NCs) that can release the entrapped corrosion inhibitor benzotriazole (BTA) at neutral conditions. The NCs are prepared using layer-by-layer assembly of poly(diallyldimethyl ammonium chloride) (PDADMAC) and poly(acrylic acid) (PAA) on kaolinite surface at different pH and salt conditions. The inhibitor is entrapped within polyelectrolyte multilayer in the assembly step. In the absence of salt, stable NCs with BTA are prepared at pH 8/5 for adsorption of PDADMAC and PAA layers, respectively. In the presence of 0.01 M NaCl, stable suspension of NCs cannot be prepared at these pH values. Instead, stabilized suspension of NCs is obtained at pH 8/8 of both polyelectrolyte solutions, which is attributed to the stronger electrostatic interactions between PDADMAC and more highly charged PAA chains. Larger amount of BTA is measured in the NCs prepared in the presence of salt.