engleski

Effect of the Spacer Length on the Association and Adsorption Behavior of Dissymmetric Gemini Surfactants

A series of dissymmetric gemini surfactants with a general formula  C12H25(CH3)2N(CH2)sN(CH3)2C14H29 Br2 designed as 12-s-14, where s = 2, 6 and 10, was synthesized and their physicochemical properties were investigated. The effect of the spacer length on the Krafft temperature, adsorption at the air/solution interface and association in aqueous solution was studied by tensiometry, conductometry and cryo- transmission electron microscopy. The Krafft temperature was found to increase linearly with the spacer length. In the submicellar concentration range the dissymmetric 12-s-14 surfactants display ion pairing and premicellar association. Adsorption at the air/solution interfaces and micellization in aqueous solution are similar to the behavior of their symmetric counterparts and strongly depend on the spacer length.

gemini surfactants ; adsorption ; association ; Krafft point

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