title: Morphology, thermal behavior, and stability of self-assembled supramolecular tubules from lysine-based surfactants.
abstract: Synthetic amino acid-based surfactants possess versatile aggregation properties and are typically more biocompatible and biodegradable than surfactants with conventional headgroups. This opens the possibility of a myriad of specialty applications, namely in pharmaceutics, cosmetics, biomedicine, and nanotemplating chemistry. In this work, we have investigated the interfacial and self-assembling properties in aqueous medium of novel double-chained lysine-based surfactants, with particular focus on the behavior of the dodecyl derivative, 12Lys12. Upon cooling from dilute isotropic micellar solutions, this surfactant crystallizes into micrometer-sized tubular structures that induce gelation of the system. The tubules have been characterized in terms of morphology, assembly process, thermal behavior, and stability, by using differential scanning calorimetry, light and scanning electron microscopy, and deuterium NMR. Possible mechanisms for tubule assembly are discussed, on the basis of surfactant molecular shape, H-bonding and electrostatic interactions, and chirality effects.
authors.affiliation: Centro de Investigação em Química, Department of Chemistry and Biochemistry, University of Porto, Rua do Campo Alegre, s/n, 4169-007 Porto, Portugal.
authors.forename: Rodrigo O
authors.initials: RO
authors.lastname: Brito
authors.forename: Isabel S
authors.initials: IS
authors.lastname: Oliveira
authors.forename: Maria J
authors.initials: MJ
authors.lastname: Araújo
authors.forename: Eduardo F
authors.initials: EF
authors.lastname: Marques
mesh_terms: D000838:Anions; D007851:Dodecanol / Q000737:chemistry*; D006863:Hydrogen-Ion Concentration; D008239:Lysine / Q000737:chemistry*; D008823:Micelles; D008855:Microscopy, Electron, Scanning; D015394:Molecular Structure; D013500:Surface Tension; D013501:Surface-Active Agents / Q000737:chemistry*; D013816:Thermodynamics
chemical_list: D000838:Anions; D008823:Micelles; D013501:Surface-Active Agents; D007851:Dodecanol; D008239:Lysine