Abstract: The stopped-flow technique combined with Aniannson-Wall theory was used to study the kinetics of micelle formation-breakup in aqueous solution of quaternary ammonium Gemini surfactant of the alkanediyl-α-ω-bis(dodecyldimethyl ammonium bromide) type with alkanediyl=(CH₂)₂, (CH₂)₃, (CH₂)₄ and (CH₂)₆. The kinetic results show that the relaxation time of micelle formation-breakup τ₂ is dependent on the spacer chain length, the concentration of the surfactants, the concentration of antiionic and the temperature. The quaternary ammonium Gemini surfactants show a decrease in relaxation time of micelle formation-breakup, as the spacer chain length is increased. Above 293 K, the 1/τ₂ comes to a minimum value when the concentration of anti-ionic is increased. The effect of nucleus formation enthalpy provides evidence in support of our proposed mechanism of the micelle formation-breakup for quaternary ammonium Gemini surfactant with different spacer chain lengths.

Key words: Quaternary ammonium Gemini surfactants, Stopped-flow method, Relaxation time