title: Spectrofluorimetric determination of second critical micellar concentration of SDS and SDS/Brij 30 systems.
abstract: Potentially useful stead-state fluorimetric technique was used to determine the critical micellar concentrations (CMC(1) and CMC(2)) for two micellar media, one formed by SDS and the other by SDS/Brij 30. A comparative study based on conductimetric and surfacial tension measurements suggests that the CMC(1) estimated by the fluorimetric method is lower than the value estimated by these other techniques. Equivalent values were observed for SDS micelles without Brij 30 neutral co-surfactant. The use of acridine orange as fluorescent probe permitted to determine both CMC(1) and CMC(2). Based on it an explanation on aspects of micelle formation mechanism is presented, particularly based on a spherical and a rod like structures.
authors.affiliation: Departamento de Química-FFCLRP, Universidade de São Paulo, Ribeirão Preto, Brazil.
authors.forename: Ana Paula
authors.initials: AP
authors.lastname: Romani
authors.forename: Antonio Eduardo da Hora
authors.initials: AE
authors.lastname: Machado
authors.forename: Noboru
authors.initials: N
authors.lastname: Hioka
authors.forename: Divinomar
authors.initials: D
authors.lastname: Severino
authors.forename: Mauricio S
authors.initials: MS
authors.lastname: Baptista
authors.forename: Lúcia
authors.initials: L
authors.lastname: Codognoto
authors.forename: Maira R
authors.initials: MR
authors.lastname: Rodrigues
authors.forename: Hueder Paulo Moisés
authors.initials: HP
authors.lastname: de Oliveira
mesh_terms: D000165:Acridine Orange; D005470:Fluorometry / Q000379:methods*; D008823:Micelles; D000077423:Polidocanol; D011092:Polyethylene Glycols / Q000737:chemistry*; D012967:Sodium Dodecyl Sulfate / Q000737:chemistry*; D013501:Surface-Active Agents / Q000737:chemistry
chemical_list: D008823:Micelles; D013501:Surface-Active Agents; D000077423:Polidocanol; D012967:Sodium Dodecyl Sulfate; D011092:Polyethylene Glycols; D000165:Acridine Orange