Effects of pH, temperature and ionic strength on aggregation behavior of dodecyldiethoxylamine oxide
The isoelectric point of dodecyldiethoxylamine oxide (DDEAO) containing hydroxyethyl groups was determined with the method of acid-base titration. The isoelectric point value of DDEAO is 7.8. The effects of pH, temperature and ionic strength on the aggregation behavior of DDEAO were investigated by surface tension measurements. The results show a good surface activity over a large pH range, especially under weakly acidic conditions. The surface activity of DDEAO increases trend increasing temperature. The thermodynamic parameters were also evaluated and the results show that the micelle formation is entropy-driven within the temperature range investigated. CMC values decrease with increases in ionic strength. The packing parameters (P) were evaluated and ensure the formation of vesicles for DDEAO at various pH values, which is expected to have potential applications in some fields, such as in nanomaterials synthesis and the application in drug delivery.
Synthesis and properties of dodecyldiethoxylamine oxide
Dodecyldiethoxylamine oxide (DDEAO) was synthesized by the reaction of dodecyldiethoxylamine with hydrogen peroxide in water as the solvent. Surface activity, wetting ability and emulsifying capacity were investigated and compared with that of dodecyldimethylamine oxide (DDMAO). Results indicate that the critical micelle concentration (CMC) of DDEAO is lower than that of DDMAO, while its surface tension at CMC (γCMC) is slightly higher. The wetting ability of DDEAO is similar to that of DDMAO. For its capacity of emulsifying liquid paraffin, DDEAO is found to be better than DDMAO, but it is the opposite for emulsifying soybean oil. The foaming properties and thickening function of DDEAO in mixtures with alcohol ether sulfate and alkylbenzene sulfonate were also studied. As expected, complex surfactant systems exhibit good foaming ability and DDEAO exhibits a good thickening function.