Wormlike Micelles of Hexaoxyethylene Decyl C sub(10)E sub(6) and Tetradecyl C sub(14)E sub(6) Ethers Containing n-Dodecanol

Wormlike micelles formed with the surfactant hexaoxyethylene decyl C sub(10)E sub(6) and tetradecyl C sub(14)E sub(6) ethers were studied by static (SLS) and dynamic light scattering (DLS) experiments to examine variation of the micellar characteristics with uptake of n-dodecanol. The SLS results have been analyzed by the light scattering theory for micelle solutions to yield the molar mass M sub(w)(c) as a function of concentration c along with the cross-sectional diameter d of the micelle. The apparent hydrodynamic radius R sub(H,app)(c) determined by DLS as a function of c is also successfully analyzed by a fuzzy cylinder theory which takes into account the hydrodynamic and direct collision interactions among micelles, allowing us to evaluate the stiffness parameter lambda super(-1). It has been found that the micellar length increases with increasing surfactant weight fraction w sub(s) or with raising temperature T irrespective of the composition of n-dodecanol content in the micelles. The length of the micelles at fixed w sub(s) and T steeply increases with increasing weight fraction w sub(d) of n-dodecanol. The length of the C sub(14)E sub(6) micelles is extremely larger than that of the C sub(10)E sub(6) micelles. The values of d and lambda super(-1) are found to increase with increasing w sub(d). It has been found that the increase in lambda super(-1) is more significant for the micelles of the surfactant molecules with shorter hydrophobic chain length.