Self-Assembly of Complex Salts of Cationic Surfactants and Anionic-Neutral Block Copolymers. Dispersions with Liquid-Crystalline Internal Structure

Author(s)

Vitorazi, Leticia ^[1] ; Berret, Jean-Francois ^[2] ; Loh, Watson ^[1]

Affiliation

^[1] Univ Estadual Campinas, UNICAMP, Inst Chem, Sao Paulo - Brazil

^[2] Univ Paris 07, UMR 7057, CNRS, F-75205 Paris - France

• Document type: Journal article
• Source: Langmuir; v. 29, n. 46, p. 14024-14033, NOV 19 2013.
• Web of Science Citations: 15

Abstract

We report the synthesis of complex salts made from the cationic surfactant dodecyltrimethylammonium and diblock copolymers poly(acrylic acid)-block-poly(acrylamide) of different molecular weights. In water, the complex salts self-assemble into stable hierarchical aggregates with a dense core and a diffuse shell. In contrast to earlier reports, the surfactant/polymer aggregates exhibit a liquid crystalline structure of Pm3n cubic symmetry. The crystal structure is analogous to that obtained with homopolymer. Size and aggregation numbers were estimated from a combination of light and small-angle X-ray scattering experiments. It is found that the size of the aggregates decreases with increasing diblock asymmetry. The complex salt methodology presents many advantages, among which to be insensitive to the preparation conditions and to the mixing pathway. (AU)

• FAPESP's process: 10/52411-6 - Interaction of anionic block copolymers with cationic surfactants and inorganic nanoparticles: structural and thermodynamic characterization
• Grantee: Watson Loh
• Support Opportunities: Regular Research Grants