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TitleDODAB and DODAC bilayer-like aggregates in the micromolar surfactant concentration domain
Author(s)Feitosa, Eloi
Alves, Fernanda Rosa
Castanheira, Elisabete M. S.
Oliveira, M. Elisabete
Nile Red
Cationic vesicles
Melting temperature
Steady-state fluorescence
Cationic vesicle
Issue date10-Feb-2009
JournalColloid and Polymer Science
Citation"Colloid and Polymer Science". ISSN 0303-402X. 287:5 (2009) 591-599.
Abstract(s)In the millimolar concentration domain (typically 1 mM), dioctadecyldimethylammonium bromide and chloride (DODAX, X representing Br- or Cl- counterions) molecules assemble in water as large unilamellar vesicles. Differential scanning calorimetry (DSC) is a suitable technique to obtain the melting temperature (Tm) characteristic of surfactant bilayers, while fluorescence spectroscopy detects formation of surfactant aggregates, like bilayers. These two techniques were combined to investigate the assemble of DODAX molecules at micromolar concentrations, from 10 to 100 micromolar. At 1 mM surfactant, Tm ~ 45 ºC and 49 oC, respectively for DODAB and DODAC. DSC and fluorescence of Nile Red were used to show the formation of DODAX aggregates, at the surfactant concentration as low as 10 micromolar, whose Tm decreases monotonically with increasing DODAX concentration to attain the value for the ordinary vesicles. The data indicate that these aggregates are organized as bilayer-like structures.
AccessOpen access
Appears in Collections:CDF - FAMO - Artigos/Papers (with refereeing)

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