Persistence Length of Wormlike Micelles Composed of Ionic Surfactants: Self-Consistent-Field Predictions
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- 作者：Y. Lauw ; F. A. M. Leermakers ; M. A. Cohen Stuart
- 刊名：Journal of Physical Chemistry B
- 出版年：2007
- 出版时间：July 19, 2007
- 年：2007
- 卷：111
- 期：28
- 页码：8158 - 8168
- 全文大小：237K
- 年卷期：v.111,no.28(July 19, 2007)
- ISSN：1520-5207
文摘
The persistence length of a wormlike micelle composed of ionic surfactants CnEmXk in an aqueous solvent ispredicted by means of the self-consistent-field theory where CnEm is the conventional nonionic surfactant andXk is an additional sequence of k weakly charged (pH-dependent) segments. By considering a toroidal micelleat infinitesimal curvature, we evaluate the bending modulus of the wormlike micelle that corresponds to thetotal persistence length, consisting of an elastic/intrinsic and an electrostatic contribution. The total persistencelength increases with pH and decreases with increasing background salt concentration. We estimate that theelectrostatic persistence length 
scales with respect to the Debye length 
-1 as 
~ -p where p 
1.98for wormlike micelles consisting of C20E10X1 surfactants and p 1.54 for wormlike micelles consisting ofC20E10X2 surfactants. The total persistence length 
is a weak function of the head group length m but scaleswith the tail length n as 
~ nx where x 2-2.6, depending on the corresponding head group length.Interestingly, 
varies nonmonotonically with the number of charged groups k due to the opposing trends inthe electrostatic and elastic bending rigidities upon variation of k.
scales with respect to the Debye length -1 as ~ -p where p 1.98for wormlike micelles consisting of C20E10X1 surfactants and p 1.54 for wormlike micelles consisting ofC20E10X2 surfactants. The total persistence length is a weak function of the head group length m but scaleswith the tail length n as ~ nx where x 2-2.6, depending on the corresponding head group length.Interestingly, varies nonmonotonically with the number of charged groups k due to the opposing trends inthe electrostatic and elastic bending rigidities upon variation of k.