Shape and position of 4-aminophthalimide (4-AP) time-resolved emission spectra (TRES) versus sodium dodecyl sulfate sds concentration in micellar solutions: the partitioning of 4-AP in the micellar phase and in water surrounding the micelles.
Time-resolved emission spectra (TRES) of 4-aminophthalimide (4-AP) dissolved in water solutions of sodium dodecyl sulfate (SDS) for three surfactant concentrations (0.05, 0.15, and 0.45 M) have been determined. The fraction of 4-AP dissolved in the water phase surrounding the micelles has been shown to increase with decreasing concentration of the surfactant. To obtain TRES of 4-AP present exclusively in micelles, a method of subtraction of the contribution of the emission originating from 4-AP present in the water phase surrounding the micelles from the total emission of the probe dissolved in SDS solution has been proposed. The consequences of failing to take into account the partitioning of 4-AP between the water and micellar phases are illustrated by some exemplary TRES results, taken before and after the subtraction of the emission originating from 4-AP present in the water phase. Together with the time of appearance and presence of isoemissive points in the time-resolved area-normalized emission spectra (TRANES), these results have shown a clear dependence of the rate and character of the 4-AP TRES changes on the SDS concentration. In connection with our earlier results and literature data, it has been concluded that the concentration of the water solubilized in micelles is the main factor determining the rate and character of these changes.
Maciejewski
Andrzej
A
Center for Ultrafast Laser Spectroscopy and Department of Physics, Adam Mickiewicz University, Umultowska 85, 61-614 Poznań, Poland.
Kubicki
Jacek
J
Dobek
Krzysztof
K
D055598:Chemical Phenomena; D002627:Chemistry, Physical; D008823:Micelles; D010797:Phthalimides / Q000737:chemistry*; D012967:Sodium Dodecyl Sulfate / Q000737:chemistry*; D012995:Solubility; D013050:Spectrometry, Fluorescence; D013501:Surface-Active Agents / Q000737:chemistry*; D014867:Water / Q000737:chemistry
D008823:Micelles; C458259:N-aminophthalimide; D010797:Phthalimides; D013501:Surface-Active Agents; D014867:Water; D012967:Sodium Dodecyl Sulfate