Effect of magnetic nanoparticle coating on their electrochemical behaviour at a polarized liquid/liquid interface

Abstract

The interface between two immiscible electrolyte solutions (ITIES) can act as a platform for the assembly of nanoscale materials. Here, we study the effect of the coated magnetic nanoparticles most commonly used in biomedicine, on their interfacial properties, analysing the effect of applied potential on their interfacial behaviour, and the interactions that occur during these perturbations. The importance of this study is based on the similarity of the water/organic solvent interface with that generated at the cell membrane in the extra-cellular environment. Magnetite nanoparticles were successfully obtained by co-precipitation method, and were coated with chitosan and diethylaminoethyl dextran. Microstructure, magnetic properties and the electrochemical behaviour of the nanoparticles at liquid/liquid interfaces were studied. The presence of these nanoparticles at the interface facilitates the ion transfer process and increases the value of capacity charge, revealed by adsorption curves. These effects depend on the coating polymer and the amount of magnetic nanoparticles adsorbed at the interface, being higher for nanoparticles coated with chitosan. The main difference in the interfacial behaviour of the coated nanoparticles is due to the distribution of the amine groups in the chain of both polymers, since in chitosan the amine groups interact easily with ions present in both phases, because it has a linear structure, different from the branched diethylaminoethyl dextran. The results obtained in this work contribute to understanding the interactions between polymers and magnetic nanoparticles and demonstrate that liquid/liquid interfaces can be used successfully to analyse the effect that different coatings have on their interfacial behaviour.