Spontaneous vesicle formation in catanionic mixtures of amino acid-based surfactants: Chain length symmetry effects

• Tipo: Artigo em Revista Científica Internacional
• Data: 2008

Autores

Eduardo F Marques (Autor) FCUP; Rodrigo O Brito (Autor) Outra; Sandra G Silva (Autor) Outra; Enrique E Rodriguez Borges (Autor) FCUP; Maria Luisa do Vale (Autor) FCUP; Paula Gomes (Autor) FCUP; Maria J Araujo (Autor) FCUP; Olle Soderman (Autor) Outra

Revista

Título: Langmuir

Vol. 24 Nº 16

Páginas: 11009-11017

ISSN: 0743-7463

Editora: American Chemical Society

Indexação

ISI Web of Knowledge - 57 Citações

Scopus - 62 Citações

Classificação Científica

FOS: Ciências da engenharia e tecnologias > Engenharia dos materiais

Outras Informações

ID Authenticus: P-003-VJF

DOI: 10.1021/la801518h

Abstract (EN): The use of amino acids for the synthesis of novel surfactants with vesicle-forming properties potentially enhances the biocompatibility levels needed for a viable alternative to conventional lipid vesicles. In this work, the formation and characterization of catanionic vesicles by newly synthesized lysine- and serine-derived surfactants have been investigated by means of phase behavior mapping and PFG-NMR diffusometry and cryo-TEM methods. The lysine-derived surfactants are double-chained anionic molecules bearing a pseudogemini configuration, whereas the serine-derived amphiphile is cationic and single-chained. Vesicles form in the cationic-rich side for narrow mixing ratios of the two amphiphiles. Two pairs of systems were studied: one symmetric with equal chain lengths, 2C(12)/C(12), and the other highly asymmetric with 2C(8)/C(16) chains, where the serine-based surfactant has the longest chain. Different mechanisms of the vesicle-to-micelle transition were found, depending on symmetry: the 2C12/C12 system entails limited micellar growth and intermediate phase separation, whereas the 2C(8)/C(16) system shows a continuous transition involving large wormlike micelles. The results are interpreted on the basis of currently available models for the micelle-vesicle transitions and the stabilization of catanionic vesicles (energy of curvature vs mixing entropy).

Idioma: Inglês

Tipo (Avaliação Docente): Científica

Nº de páginas: 9