Stability of Electrostatically Stabilized Nanoparticles

The stabihty of a dispersion of particles depends upon the interplay of repulsive and attractive interactions between the particles. The athactive interaction, V, between particles arises from van der Waals interactions, while the repulsive interaction, Vr, can arise either from the electric double layer of charged particles or from the steric repulsion from an organic layer surrounding the particles. If there is an energy barrier between particles that is greater than 2kT then the dispersion is stable otherwise, the dispersion is unstable and the particles flocculate out of solution. 

Particles that are charged attract ions of the opposite polarity towards the particle s surface to maintain electrical neutrality. The concentration of these ions decays exponentially with distance away from the surface this is known as the 

A common example of particles that are stabilized due to electrostatic repulsion is that of negatively charged citrate stabiUzed gold or sUver nanoparticles. 

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