Phase transition in dioctadecyldimethylammonium bromide and chloride vesicles prepared by different methods

dc.contributorUniversidade Estadual Paulista (UNESP)
dc.creatorFeitosa, E.
dc.creatorBarreleiro, PCA
dc.creatorOlofsson, G.
dc.date2014-05-20T14:02:21Z
dc.date2016-10-25T17:09:03Z
dc.date2014-05-20T14:02:21Z
dc.date2016-10-25T17:09:03Z
dc.date2000-04-01
dc.date.accessioned2017-04-05T21:27:19Z
dc.date.available2017-04-05T21:27:19Z
dc.identifierChemistry and Physics of Lipids. Clare: Elsevier Sci Ireland Ltd, v. 105, n. 2, p. 201-213, 2000.
dc.identifier0009-3084
dc.identifierhttp://hdl.handle.net/11449/21977
dc.identifierhttp://acervodigital.unesp.br/handle/11449/21977
dc.identifier10.1016/S0009-3084(00)00127-4
dc.identifierWOS:000086633900010
dc.identifierhttp://dx.doi.org/10.1016/S0009-3084(00)00127-4
dc.identifier.urihttp://repositorioslatinoamericanos.uchile.cl/handle/2250/867453
dc.descriptionThe gel to liquid crystalline phase transition of the double-chained cationic dioctadecyldimethylammonium chloride and bromide (DODAX, X = Cl- or Br-) in aqueous vesicle dispersions prepared by non-sonication, sonication and extrusion has been investigated using high-sensitivity differential scanning calorimetry (DSC). The transition temperature (T-m) is a function of the preparation method, amphiphile concentration, vesicle curvature and nature of the counterion. DSC thermograms for DODAB and DODAC non-sonicated vesicle dispersions exhibit a single endothermic peak at T-m roughly independent of concentration up to 10 mM. Extrusion broadens the transition peak and shifts T-m downwards. Sonication, however, broadens slightly the transition peak and tends to shift T-m upwards suggesting that extrusion and sonication form vesicles with different characteristics. DODAC always exhibits higher T-m than DODAB irrespective of the preparation method. T-m changes as follows: T-m (sonicated) greater than or equal to T-m (non-sonicated) > T-m (extruded). Hysteresis of about 7 degrees C was observed for DODAB vesicle dispersions. (C) 2000 Elsevier B.V. Ireland Ltd. All rights reserved.
dc.languageeng
dc.publisherElsevier B.V.
dc.relationChemistry and Physics of Lipids
dc.rightsinfo:eu-repo/semantics/closedAccess
dc.subjectdifferential scanning calorimetry
dc.subjecttransition temperature
dc.subjectsonicated vesicles
dc.subjectnon-sonicated vesicles
dc.subjectextruded vesicles
dc.titlePhase transition in dioctadecyldimethylammonium bromide and chloride vesicles prepared by different methods
dc.typeOtro


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