Sononanoengineered magnesium-polypyrrole hybrid capsules with synergetic trigger release

This paper describes the ultrasonic-assisted preparation and characterisation of magnesium–polypyrrole hybrid capsules loaded with the organic fluorophore rhodamine 6G (Rh6G). Hybrids were prepared through sonication of magnesium and pyrrole without initiator or with Fe(III) as the polymerisation initiator in water and alcohol solutions. We studied the hybrids' morphology, ζ-potential, FTIR spectra, sonoinduced phase transformation and fluorescent properties. The properties of the obtained hybrids, as well as the dye-loading efficiency, were found to depend on the ultrasonic conditions. The fluorophore release from the free or surface sonoimmobilised capsules in aqueous solutions of different pH values and under electric current was also studied. Effective pH-responsive release, including step-wise release, was confirmed for the hybrid system. The electric current was also shown to trigger the release of hybrid capsules sonoimmobilised onto an Ni patterned ITO surface.