Effect of Triton X-100 on the stability of aqueous dispersions of copper phthalocyanine pigment nanoparticles

► The adsorption density of Triton X-100 is higher on the hydrophobic than on the hydrophilic CuPc particles. ► Some adsorbed surfactant remains irreversibly adsorbed after the solution is diluted. ► The stabilization mechanism for the hydrophobic CuPc particles is primarily steric. ► The stabilization mechanism for the hydrophilic CuPc particles is primarily electrostatic. ► For dispersions in water the zeta potential is not a good predictor of dispersion stability.