Figure 1.

Surfactants for nanoparticle stabilization. (a) Classic structure of surfactants: its amphiphilic nature is represented with a hydrophilic region and a hydrophobic region. (b) Coating of NP with surfactants: the hydrophobic region possesses an affinity for the nanoparticle surface and the hydrophilic region with an affinity for the aqueous dispersion medium. (c) Classification of surfactants according to the ionic charge in its polar group: no charge (non-ionic), positive charge (cationic), negative charge (anionic), and both positive and negative charge (amphoteric).