Spontaneous Vesicle Formation in Catanionic Mixtures of Amino Acid-Based Surfactants: Chain Length Symmetry Effects.

Forskningsoutput: TidskriftsbidragArtikel i vetenskaplig tidskrift

Abstract

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 2C 12/C 12 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).

Detaljer

Författare
  • Eduardo Marques
  • Rodrigo de Oliveira Brito
  • Sandra Silva
  • J Rodríguez-Borges
  • Maria Vale
  • Paula Gomes
  • Maria Araújo
  • Olle Söderman
Enheter & grupper
Forskningsområden

Ämnesklassifikation (UKÄ) – OBLIGATORISK

  • Fysikalisk kemi
Originalspråkengelska
Sidor (från-till)11009-11017
TidskriftLangmuir
Volym24
Utgåva nummer19
StatusPublished - 2008
PublikationskategoriForskning
Peer review utfördJa