José Campos-Terán: Alpha Cyclodextrin-SDS Self-Assembled Viscoelastic Films at the Liquid/Air Interface
Plats: Kemicentrum, Lecture hall F
A seminar by Dr. José Campos Terán, Departamento de Procesos y Tecnología, Universidad Autónoma Metropolitana, Unidad Cuajimalpa, México.
Native α-cyclodextrin (α-CD) and sodium dodecyl sulfate (SDS) are found to spontaneously form viscoelastic films at aqueous solution/air interfaces. Temperature and the relative amounts of α-CD and SDS strongly modify the viscoelastic properties of such films. Using isothermal titration calorimetry the distribution of species in the bulk solution was determined. A large number of surface techniques have been used to characterize the films, namely shape-response measurements to volume perturbations on drop hanging from a capillary, neutron reflectivity, Brewster angle microscopy, dynamic surface tension, ellipsometry and the continuous injection and oscillating drop methods to quantify their viscoeslastic behavior. It was found that these films are mainly formed by α-CD2-SDS1 inclusion complexes, reflecting the bulk solution distribution of species. Also, in order to understand this ternary system, the binary system α-CD- water was characterized both at the bulk solution and the air-solution interface where it was found that it creates a film through a slow formation kinetic and in which its composition depends on the bulk aggregates.