C of Nonionics

Use Equation 4.7 with a = 0.5 for SDS and Equation 4.9 for C12E4, and for the same values of the two surfactants have the same AG°. Hraice 

The model ineludes two key parameters in the form of ratios between lengths/sizes of A and B ehains, and an energy parameter Xbs b where Xbs Flory-Huggins 

For ionic snrfactants, the addition of short-chain alcohols decreases Xj (i.e., inereases xj ). For medium-ehain alcohols, X2 initially increases with inereasing aleohol eonemtration, then reaches a maximum and decreases as additional alcohol is incorporated into the micelle interior instead of the paUsade layer. The addition of hydroearbons, which are solubilized in the micelle interior, also prodnees a decrease in xj. In Chapter 6 we call attention to the fact that even thongh Xj is qnite small, its effect can be felt even in slow processes such as solubilization, wave motion, etc. It is noteworthy that micelles of block copolymer, PEO-PPO-PEO, also show these two time constants, which have similar intmpretations (Goldmints et al., 1997). 

FIGURE 4.7 Ti versus surfactant (SDS) concentration at different values of counterion (Na ) concentrations. Different symbols denote different concentrations of sodium perchlorate, including one which is zero. Reprinted with permission from Lessner et al. (1981). Copyright 1981 American Chemical Society. 

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Table IX. Thermodynamic Data for Surfactants Micellization at 25°C of Nonionic...

The c.m.c. of nonionic surfactants is about two orders of magnitude lower than the corresponding anionics with the same alkyl chain length. The solubility of the alcohol ethoxylates depends both on the alkyl chain length and the number of ethylene oxide units in the molecule. Molecules with an average alkyl chain length... 

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