A Thermally Stable Polyamine/Unsaturated Fatty Acid System: Gelation Behaviors and Application

Abstract

The gelation behavior of diethylenetriamine (DETA) and oleic acid (OLA) with different molar ratios in water was investigated. The gels, which were composed of lamellar phase and vesicles, were characterized using small‐angle X‐ray scattering (SAXS) and freeze‐fracture transmission electron microscopy (FF‐TEM). The responsive rheological properties were also investigated. Our results show that lamellar gels and rodlike micelles were formed successively with the increase of the DETA/OLA molar ratio. The lamellar gels exhibiting high thermal stability can be obtained in a wide range of polyamine/unsaturated fatty acid molar ratios. The mechanism of lamellar gel formation was explained by the packing parameter and the noncovalent interactions between the building blocks. Moreover, gel–sol transition can be triggered by tuning pH and ionic strength. This system has a good emulsification property, and no obvious nanoemulsion droplet coarsening is observed upon dilution after 30 days.