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ATTENTION !!! SEMINAIRE ANNULE !!! Complex salts : Controlling love and hate

Mercredi 15 juin 2016 10:00 - Duree : 1 heure
Lieu : ILL 4, Seminar Room, 71 avenue des Martyrs - Grenoble

Orateur : Lennart PICULELL (Physical Chemistry, Department of Chemistry, Lund University)

Nature offers two strong intermolecular interactions to achieve molecular (self)-assembly in water : the hydrophobic interaction, and the electrostatic attraction between + and -.

The hydrophobic interaction is the mechanism by which surfactants, lipids and other amphiphilic molecules self-assemble into aggregates of varying shape and size. The simplest example is a surfactant micelle. Conventional charged micelles are water soluble, but by using charged polymers, polyions, as their counterions, we can use the strong electrostatic attraction to bring the aggregates out of water. These "complex salts" of surfactant ions and polyions then form concentrated systems that swell in excess water, but do not dissolve completely.

Concentrated complex salts in water can form a number of interesting organized, liquid-crystalline structures, where small spherical, long rod-like, or infinite sheet-like surfactant aggregates pack in a regular fashion. For a number of years, our group has studied this self-assembly behavior systematically. Our main questions have been fundamental, but always with an eye on complex salts as interesting soft materials with potential applications :

• How do we control the structures of complex salts in water ?

• How do we control their maximum water uptake, or solubility ?

• What are the important similarities and differences in behavior between complex salts and conventional ionic surfactants (with monovalent counterions) ?

• How can we exploit our fundamental knowledge in designing materials and processes involving complex salts ?

Literature

1. Lennart Piculell : Understanding and exploiting the phase behavior of mixtures of oppositely charged polymers and surfactants in water. Langmuir, 2013, 29, 10313−10329.

2. Charlotte Gustavsson, Joaquim Li, Karen J. Edler and Lennart Piculell : Water-responsive internally structured polymer-surfactant films on solid surfaces. Langmuir, 2014, 30, 12525−12531.

3. Charlotte Gustavsson, Marc Obiols-Rabasa, and Lennart Piculell : Water-insoluble surface coatings of polyion-surfactant ion complex salts respond to additives in a surrounding aqueous solution. Langmuir 2015, 31, 6487-6496.

Contact : tellier@ill.fr

Discipline évènement : (Biologie / Chimie) - Discipline évènement : (Physique)
Entité organisatrice : (ILL)
Nature évènement : (Séminaire)
Evènement répétitif : (General ILL Seminar - College 9)
Site de l'évènement : Polygone scientifique

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