Yusof, N.S. and Khan, M.N. (2012) Quantitative correlation of counterion (x) affinity to ionic micelles and x- and temperature-induced micellar growth (spherical - wormlike micelles - vesicles) for x = 5-methyl- and 5-methoxysalicylate ions. Journal of Physical Chemistry B, 116 (7). ISSN 1520-6106, DOI PMID: 22272582.
Full text not available from this repository.Abstract
The semiempirical kinetic method has been used to determine the ratio of cetyltrimethylammonium bromide, CTABr, micellar binding constants of counterions X (K(X)) and Br (K(Br)), i.e., K(X)/K(Br) (= R(X)(Br)) for X = dianionic 5-methyl- and 5-methoxysalicylate ions. The values of K(X) and K(Br) have been derived from the kinetic parameters obtained in the presence of spherical/nonspherical and spherical micelles, respectively. The values of R(X)(Br) remain essentially independent of [CTABr] within its range 0.005-0.015 M for both dianionic 5-methyl- and 5-methoxysalicylate ions. The increase in temperature from 35 to 55 °C decreases the values of R(X)(Br) from 796 to 53 for 5-methylsalicylate ions and from 89 to 7.0 for 5-methoxysalicylate ions. Rheological properties of 0.015 M CTABr solutions containing ≥0.01 M counterionic salt, M(2)X, show indirectly the presence of unilamellar vesicles, ULV, and long linear, entangled, and branched wormlike micelles, WM, at, respectively, 35 and 55 °C for X = dianionic 5-methylsalicylate ion. However, such studies show WM and probable spherical micelles, SM, at, respectively, 35 and 55 °C for X = dianionic 5-methoxysalicylate ions. It has been shown that, at a constant [CTABr], the micellar structural transitions from SM-to-WM-to-vesicles may be correlated quantitatively with the values of R(X)(Br) regardless of whether such micellar structural transitions occur due to variation in the values of [M(2)X] at a constant temperature or due to variation in temperature at a constant [M(2)X].
| Item Type: | Article |
|---|---|
| Funders: | UNSPECIFIED |
| Additional Information: | Department of Chemistry, Faculty of Science, University of Malaya , 50603 Kuala Lumpur, Malaysia |
| Uncontrolled Keywords: | Chemistry |
| Subjects: | Q Science > QD Chemistry R Medicine |
| Divisions: | Faculty of Science > Department of Chemistry |
| Depositing User: | Mr. Faizal Hamzah |
| Date Deposited: | 22 Mar 2012 02:19 |
| Last Modified: | 11 Dec 2014 09:18 |
| URI: | http://eprints.um.edu.my/id/eprint/2963 |
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