Structure of cationic surfactant micelles from molecular simulations of self-assembly

• Type: Article in International Scientific Journal
• Date: 2010

Authors

Miguel Jorge (Author) FEUP

Journal

Title: Journal of Molecular Structure: THEOCHEM

Vol. 946 No. 1-3

Pages: 88-93

ISSN: 0166-1280

Publisher: Elsevier B.V.

Indexing

ISI Web of Science

Scopus

INSPEC

Scientific classification

FOS: Engineering and technology > Chemical engineering

CORDIS: Technological sciences > Engineering > Chemical engineering

Other information

DOI: 10.1016/j.theochem.2009.09.054

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.

Language: English

Type (Professor's evaluation): Scientific

No. of pages: 6