Fluorescence is widely used to detect functional groups and ions, and peptides are used in various fields due to their excellent biological activity.

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Diacyl amino acid surfactant was prepared using lauroyl chloride and L-lysine. The structure of the synthesized surfactant was confirmed by infrared spectroscopy and mass spectroscopy. The ultralow interfacial tension could be achieved when the diacyl amino acid surfactant is mixed with sulfonate in the presence of polymer as well as absence of polymer. Core flood experiments showed that 17.8 % additional oil could be recovered by injection of 0.3 pore volume of surfactantpolymer solution, making the total oil recovery reach 66.1 %.

In this paper, didodecylmethyl hydroxyl sulfobetaine was synthesized by reaction of didodecylmethyl amine with sodium 2-hydroxy-3-chloro propanesulfate. The interfacial tensions between Dagang crude oil and solution of the surfactants, solution of surfactant-polymer mixtures were measured. The effects of surfactant concentration and aging time on the interfacial tension were investigated. It is found that the synthesized betaine surfactant could reduce the interfacial tension to ultra-low without alkali, alcohol and the other additives in the absence of or presence of polymer. The surfactant-polymer system could lower the interfacial tension to ultra-low, even was aged for more than 2 weeks. The sand-pack flooding tests indicated that, with 0.2 wt% of the betaine and with 1,500 mg/L of polymer, 16.89 % of an additional OOIP (original oil in place) was recovered from a sand pack. This result suggested that the didodecylmethyl hydroxyl sulfobetaine might be a good surfactant candidate for enhanced oil recovery.

The human disorders associate with amyloid aggregation, such as Alzheimer's disease and Parkinson's disease, afflicting the lives of millions worldwide. When peptides and proteins in the body are converted to...