Synthesis of stable zinc-phosphate micro/nanoparticles under acid and alkaline conditions

In the present work, we synthesize zinc-phosphate particles (Zn ₃ (PO ₄ ) ₂ ) of micro and nanometric sizes (ZnPMCPs y ZnPNPs) through chemical reduction in acidic and alkaline conditions in order to obtain stable colloidal solutions through resuspension of the particles. In acidic media, the addition of hydrochloric acid (HCl), citric acid (AC), or ascorbic acid (AA) created spheric structures with a zeta potential superior to +100 mV. On the other hand, the addition of ammonium hydroxide (NH ₄ OH) created oval flat-shaped structures with zeta potential lower than -53.9 mV thus showing an agglomeration tendency in alkaline media. Therefore, these findings indicate that HCl was the most effective media for resuspension, which allowed the obtention of nanoparticles with an average size smaller than 25 nm and highly stable, which makes this an easy and reproducible method. The results from this study present a new strategy for the obtention of micro/nanoparticles with high colloidal stability, which can be recovered from previous resuspension processes without losing their stability and have potential applications in the design of biomedical and anticorrosive coatings.