Fluorescence study of solubilization of L-α-dilauroylphosphatidylethanolamine in the mixed micelles with monomeric and dimeric cationic surfactants

The mixed micelle formation between L-alpha-dilauroylphosphatidylethanolamine (DLPE) and a series of monomeric and dimeric cationic surfactants have been studied with the help of steady state fluorescence technique. The micelle formation process has been detected by plotting the emission intensities of solubilized fluorescence probes such as 5(6)-carboxyfluorescein (CF) and pyrene (Py) in the hydrophobic environment of mixed micelles. The mixed micelle process has been found to be facilitated in the presence of monomeric surfactants with higher hydrophobicities. In the case of dimeric surfactants, the steric hindrances generated by both the dimeric head group as well as twin hydrophobic tails have delayed the mixed micellization. The results have been further supported by evaluating the mean aggregation number (N-agg) of the mixed micelles and the collisional quenching rate constant. (c) 2005 Elsevier B.V. All rights reserved.