オリゴソープの部分モル容積による分類とその界面活性との相関

抄録

Surface active properties of anionic oligosoap homologues prepared from alternating cooligomers of maleic acid derivatives and alkyl vinyl ethers having C₂C₁₆ alkyl groups were measured and classified by the differences of their partial molal volumes in aqueous solutions, that is, the ratios (R) of the observed partial base molal volumes (φ_υ⁰) to the calculated ones (the summation of atomic volume) were introduced as an index for the classification, and this idea was applicable especially to the oligosoaps having C₁₀C₁₆ side chain while the corresponding C₂ and C₄ derivatives were not fitted owing to their polyelectrolyte behaviors.
It was ascertained that solubilizing and emulsifying powers of aqueous oligosoap solutions were colligatively estimated by R values, independently on their chemical structures. Furthermore, it was found that there was a minimum in the plot of surface tension vs. alkyl side chain length of oligosoaps, and such phenomenon was attributed to the inhibition of surface adsorption of originally bulky and immobile oligosoap molecules in aqueous solution owing to the strong trend of their intermolecular aggregation. Namely, C₁₆ derivative seems to give a high surface tension (68 dyn/cm) near that of water in aqueous solutions, as the result that their surface adsorptions at the air-solution interface competed with their own intermolecular aggregations. Furthermore, wetting, dispersing, and flocculating behaviors of oligosoaps were also examined.