3. February 2021
Is the electric charge present at the interface of the nanoparticle surface with a polar fluid such as water. The water contains positive and negative ions, which interact with the particle surface. If the number of adsorbed e.g. positive ions exceeds the number of negative ions, surface charge would be positive. Since direct measurement of the surface charge of particles measured is difficult, the zeta potential is calculated as a proxy for the surface charge.