Abstract: Cationic Gemini surfactant, ethanediyl-α,β-bis(cetyldimethylammonium bromide)(16-2-16), was synthesized and characterized. The dynamic surface and interface tensions have been measured using pendant drop method on the air-water surface and dodecane-water interface. The relative contact angle of the aqueous solution on the silica gel powder has been obtained by modified Washburn method. The relationship between the contact angle and the dynamic surface (interface) tension has been discussed. Compared with conventional cationic surfactants, cetyldimethylammonium bromide(CTAB，cmc 1.0 ×10－3 mol•L－1), 16-2-16 has very low cmc value (1.8 ×10－5 mol•L－1). The most hydrophilic condition between the surfactant aqueous solution and the modified silica powder appears near the cmc for both 16-2-16 and CTAB. The best laboratory mimic oil recovery(Fig.1 and Table 2) is also reached around the cmc for the two surfactants, but the efficiency for 16-2-16(68％) is higher than the one for CTAB(63％).

Key words: Cationic Gemini surfactants, Critical micelle concentration(cmc), 　Dynamic surface tension, Wettability, Mimic oil recovery