화학공학소재연구정보센터
Applied Surface Science, Vol.261, 237-241, 2012
Adsorption kinetics of 3-alkoxy-2-hydroxypropyl trimethyl ammonium chloride at oil-water interface
Dynamic interfacial tension (DIT) between aqueous solution of 3-alkoxy-2-hydroxypropyl trimethyl ammonium chloride (R(n)HTAC) and n-octane was measured using spinning drop method. The effects of R(n)HTAC concentration (the concentration below the CMC) and temperature on DIT have been investigated. The cause of the change of DIT with time has been discussed. The effective diffusion coefficient, D-a, and the adsorption barrier, epsilon(a), have been obtained with extended Word-Tordai equation. The results show that the higher the concentration of the surfactant is, the smaller the DIT will be and the lower the curve of the DIT, and the aqueous R(n)HTAC solutions follow a mixed diffusion-activation adsorption mechanism. With increase of R(n)HTAC concentration in the bulk solution, D-a decreases and epsilon(a) increases. D-a of aqueous R(14)HTAC solution decreases from 0.090 x 10(-13) m(2) s(-1) to 0.081 x 10(-13) m(2) s(-1) and epsilon(a) increases from 10.12 kJ mol(-1) to 11.89 kJ mol(-1), with the temperature increasing from 30 degrees C to 50 degrees C. This phenomenon indicates that the diffusion tendency becomes weak with the strengthening of the interaction between the surfactant molecules and that the thermo-motion of molecules benefits interface adsorption. (C) 2012 Elsevier B. V. All rights reserved.