両性-非イオン界面活性剤混合系の溶液物性DMLL-C_mPOE₂₀二成分系のクラフト点及び表面張力

抄録

The solution properties of mixed amphoteric-nonionic surfactant systems in aqueous solutions were studied in terms of Krafft points and surface tension. The systems examined were N^α, N^α-dimethyl-N^ε-acyllysine (DMLL) -alkyl poly (oxyethylene) ethers (C_mPOE₂₀; m=12, 14, 16 and 18). The Krafft point of DMLL decreased with increasing molar ratio of C_mPOE₂₀, becoming less than 0°C at a certain molar ratio. The Krafft point of DMLL mixed with a nonionic surfactant possessing a long alkyl chain was lower than that mixed with nonionic surfactant with a short alkyl chain. The surface tension of each mixed surfactant solution decreased with increasing concentration of DMLL. The cmc values of the mixed systems decreased with increasing to alkyl chain length of C_mPOE₂₀. These properties attributed to increased molecular interaction between DMLL and C_mPOE₂₀ in mixed micelles with increasing alkyl chain length in nonionic surfactants.