Patterns of the Formation of Antimicrobial Micro/Nanocomposites during the Oxidation of Bimetallic Al/Zn Nanoparticles

Resumo

Porous composites of different phase composition are synthesized via oxidation in a water–ethanol mixture of bimetallic Al/Zn nanoparticles obtained through a joint electrical explosion of aluminum and zinc wires in an argon atmosphere. It is found that the oxidation of aluminum and the formation of boehmite nanosheets proceed in solutions containing 7‒20 wt % of water. At water contents over 20 wt %, the almost complete oxidation of aluminum is followed by the onset of zinc oxidation, resulting in the formation of composites containing boehmite nanosheets and hexagonal plates enriched with zinc oxide. Composites synthesized in this way display high antimicrobial activity against bacteria, due mainly to the release of Zn²⁺ ions into the solution. The greatest antimicrobial activity is observed in composites that simultaneously contain AlOOH, Al, ZnO, and Zn phases. The strong migration of Zn²⁺ ion is due to the structure of these composites, in which the active zinc surface grows as a result of the availability of ZnO plates located between the boehmite nanosheets. The boehmite nanosheets ensure stability of the composite structure and electrostatic interaction with bacteria.