Abstract: The dilational viscoelastic properties of 4,5-diheptyl-2-propylbenzene sulfonate (DHPBS) at the decane/water interface were investigated with a spinning drop tensiometer. The instrument of the spinning drop tensiometer SVT20N and the correlative experimental method were discussed in detail. The influence of oil drop volume, rotational speed, and oscillating amplitude on the interfacial dilational modulus were expounded. Experimental results show that spinning drop analysis is a novel method for probing interfacial dilational properties and has good prospects for application in the measurement of low interfacial tension phenomena.

Key words: Spinning drop analysis, Sodium alkyl benzene sulfonate, Interfacial dilational property, Dilational modulus