Colloid stability of hydrophylic latexes
Results of coagulation experiments on negatively charged polystyrene latexes are reported. The different latex dispersions were stabilized by electrostatic, electrosteric and steric mechanisms. For the electrostatic and electrosteric stabilized dispersion the effectiveness of monovalent cations as coagulants increases according to the lyotropic sequence. For sterically stabilized latex dispersions monovalent cations as coagulants proved to be ineffective. With sodium tetraphenyl borate a narrow instability region at low electrolyte concentration was detected. The specific ion effects were evaluated and interpreted in the light of hydration regulation. The hydration forces may be modified or regulated by exchanging ions of different hydration on the surfaces of approaching particles.
Key wordsLatexes stability adsorption ion effects coagulation
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