The Stability of Detonation Nanodiamond Hydrosols in the Presence of Salts and Surfactants

Abstract

The regions of stability and coagulation of hydrosols of oxidized detonation nanodiamonds in the presence of inorganic salts and surfactants of different types have been determined. Concentration C_c of inorganic salts corresponding to the onset of the growth of aggregates in a hydrosol dramatically decreases with an increase in coagulating ion charge z: C_c ~ z^−5.3. Anionic and nonionic surfactants stabilize dispersions of nanodiamonds, while additives of cationic and zwitterionic surfactants cause coagulation. The study of the coagulating effect of alkylpyridinium chlorides has shown that the coagulation threshold halves upon elongation of the hydrocarbon chain in a surfactant molecule by a СН₂ group.