| Autor: |
Walter, R., Ricka, J., Quellet, C., Nyffenegger, R., Binkert, T. |
| Zdroj: |
Macromolecules; May 20, 1996, Vol. 29 Issue: 11 p4019-4028, 10p |
| Abstrakt: |
Time-resolved fluorescence depolarization is applied to investigate the association of sodium n-dodecyl sulfate (SDS) micelles with poly(N-isopropylacrylamide) in aqueous solutions using an amphiphilic fluorescent probe (3-perylenedodecanoic acid) which is incorporated into the SDS micelles. First, the effect of the surfactant concentration was measured: in the presence of the polymer, above the critical aggregation concentration (CAC) of SDS, the rotational relaxation of the probe exhibits a slow and a fast component. The relaxation time of the fast component is the same as in a polymer-free solution above the CMC of SDS where, however, only one component is observed. The slower relaxation time is attributed to polymer-bound micelles which incorporate polymer segments into their core. Second, the effect of the temperature induced coil−globule transition is investigated: in the course of the transition the rotational motion slows down almost 10-fold, indicating that the probe remains firmly associated with the polymer even in its dense globular state. |
| Databáze: |
Supplemental Index |
| Externí odkaz: |
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