Measurement of the rates of detergent exchange between micelles and the aqueous phase using phosphorescent labelled detergents
Phosphorescence quenching is used to measure micelle-probe detergent dynamics. For phosphorescent detergent probes with varying hydrocarbon length the rate constants from escape (K-) from cationic host micelles are measured using cobalt(III) hexamine as an aqueous soluble triplet quencher. For 10-(4-bromo-1-naphthoyl) decyltrimethylammonium bromide (BND-10), K- is 3.2 x 10/sup 3/ S/sup -1/, and K+, the reentry rate constant, is 5.7 x 10/sup 7/ M/sup -1/ S/sup -1/ for hexadecyltrimethylammonium chloride (HDTCL) host micelles at 25 C. The log of K- is a linear function of the number of methylenes in the probe alkyl chain, in agreement with rates determined previously with relaxation methods. The apparent activation energy for escape of BND-10 from HDTCL micelles is 9 kcal/mol. Escape rates are measured for several host micelles and for micelles composed of probe detergents - self-micelles. 15 references.
- OSTI ID:
- 5589123
- Journal Information:
- J. Phys. Chem.; (United States), Vol. 85:26
- Country of Publication:
- United States
- Language:
- English
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