Jump to main content
Jump to site search
Access to RSC content Close the message box

Continue to access RSC content when you are not at your institution. Follow our step-by-step guide.


Issue 29, 2017
Previous Article Next Article

Precipitating polyelectrolyte–surfactant systems by admixing a nonionic surfactant – a case of cononsurfactancy

Author affiliations

Abstract

The formation of water insoluble polyelectrolyte/surfactant complexes (PESCs) upon mixing two homogeneous polycation/anionic surfactant and polycation/nonionic surfactant solutions is reported here. This phase separation is unexpected and differs markedly from the commonly observed enhanced solubility of colloidal systems in mixed surfactant systems. The study was performed on mixtures of the cationic biopolysaccharide chitosan (poly D-glucosamine) and mixed micelles composed of an ethoxylated fatty alcohol and its carboxylic acid terminated equivalent. The thermodynamics of mixing was probed via isothermal titration calorimetry (ITC), while the structural characterisation was conducted by means of light and neutron scattering (SANS). The results show that the substitution of a weakly anionic surfactant with its nonionic equivalent has profound effects on the interactions at very different length scales. The dilution of the ionic headgroups allows for a more efficient interaction between micelles and polymer chains, and results in an elongation of the mixed micelles which reduces the bending cost of the semi-rigid chitosan and introduces an additional attractive potential of entropic origin. In this work, as a result of a comprehensive thermodynamic and structural analysis, we demonstrate how the subtle interplay of different forces leads to such an unexpected behaviour, where the addition of a nonionic surfactant causes the phase separation of electrostatic complexes.

Graphical abstract: Precipitating polyelectrolyte–surfactant systems by admixing a nonionic surfactant – a case of cononsurfactancy

Back to tab navigation

Supplementary files

Article information


Submitted
15 Apr 2017
Accepted
28 Jun 2017
First published
29 Jun 2017

Soft Matter, 2017,13, 4988-4996
Article type
Paper

Precipitating polyelectrolyte–surfactant systems by admixing a nonionic surfactant – a case of cononsurfactancy

L. Chiappisi, S. David Leach and M. Gradzielski, Soft Matter, 2017, 13, 4988
DOI: 10.1039/C7SM00747G

Social activity

Search articles by author

Spotlight

Advertisements