抄録
The effects of alcohol and surfactant on hydration forces with aqueous oxide suspensions were investigated. It was found that the primary hydration force with silica decreased with the increasing amount of ethanol in the suspension, while the secondary hydration force with rutile increased with the same condition. The surface dehydration of silica caused by ethanol may be reponsible for the decrase in the primary hydration force. For the case of rutile, the increase in the secondary hydration force may be attributed to the increased adsorption of hydrated Na+ as observed at oxide/water interfaces in mixed solvent systems reported elsewhere
Dodecylamine-hydrochloride (DAH) was added to the rutile suspension and its effect was investigated. The result suggested that there was a hydrophobic attraction, the magnitude of which was much larger than the hydration forces. At relatively high DAH concentration and at alkaline pH, an additional repulsion not considered in the classical DLVO theory was observed with rutile. The magnitude of the repulsion was comparable to the secondary hydration force observed with rutile at high NaCl concentrations.
