Abstract (EN):
Molecular dynamics simulations of self-assembly of n-decyltrimethylammonium bromide surfactants
were performed using an atomistic model, and a detailed analysis of the spontaneously formed micellar
aggregates was carried out. This allowed for a detailed study of the structure of cationic surfactant
micelles free from any a priori assumptions regarding their size and shape. Atomic radial distribution
functions, radial density profiles and bivariate water orientation distributions were computed. Together,
they show the presence of a dry micelle core, with a hydrophobic environment similar to a liquid alkane,
a well-defined head-group layer at the interface, and an outer layer of strongly bound bromide counterions.
Water molecules penetrate the micelle as far as the innermost head site, adopting a sequence of
orientations that is akin to that observed at planar interfaces with vapor or immiscible organic solvents.
Water molecules at the exterior of the micelle are highly polarized by the electrical double-layer formed
by cationic head-groups and bromide anions, orienting themselves with their dipole vector pointing
towards the micelle core.
Idioma:
Inglês
Tipo (Avaliação Docente):
Científica
Nº de páginas:
6