Branched Chains of Arylalkyl Surfactants Effects on the Interfacial Tension Between Crude Oil/Surfactant-Alkaline Systems

The dynamic interfacial tensions between crude oil and surfactant solution were measured. The data showed that some surfactants dramatically reduced the interfacial tension as well as the tension of oil/water interface to ultralow (under 10(-2) mN/m) at a very low surfactant concentration. Moreover, different aromatic rings showed different effects on the reduction of the oil/water interfacial tension. Methylphenyl-SAM and Dimethylphenyl-SAM with proper aromatic rings on their arylalkyl chains exhibited better interfacial behaviors than Phenyl-SAM with a relative small aromatic ring (phenyl) and Naphthyl-SAM and alpha-Methylnaphthyl-SAM with larger ones (naphthyl and alpha-methylnaphthyl) on their arylalkyl chains. The authors' findings demonstrated that the above-mentioned solutions could lower the oil/water interfacial tension to ultralow over a wide surfactant concentration and alkalinity ranges.