Synthesis and properties of a branched short-alkyl polyoxyethylene ether alcohol sulfate surfactant

A branched alkyl polyoxyethylene ether alcohol sulfate, sodium isooctyl polyoxyethylene ether sulfate (i-OE3S), was synthesized and its physic-chemical properties were investigated systematically. The experiment on Krafft point gave a result that the Krafft temperature of i-OE3S was below 0 °C. The measurement of static surface tension showed that the critical micelle concentration (cmc) and surface tension at cmc (γcmc) of i-OE3S were 21.67 mmol·L− 1 and 27.4 mN·m− 1, respectively. From the results of dynamic surface tension (DST) measurements, we could obtain that the adsorption of i-OE3S at air/liquid interface is controlled by the mixed diffusion-kinetic mechanism. Spherical assemblies with a diameter in the range of 263 to 606 nm in water were observed by transmission electron microscopy (TEM). The spreading performance of i-OE3S aqueous solution on paraffin film was investigated by dynamic contact angle and the results demonstrated that i-OE3S possessed an excellent spreading ability.