Interplay between chirality and geometrical constraints in colloidal membranes
Lundi 21 janvier 2013 14:00
- Duree : 1 heure
Lieu : Laboratoire Interdisciplinaire de Physique (ex LSP), Salle 216, Bât. E - 140 Avenue de la Physique Domaine Universitaire - Saint-Martin-d’Hères
Orateur : Thomas GIBAUD (Laboratoire de Physique, ENS Lyon)
The interfacial tension between molecular species in self-assembling systems plays a crucial role in determining the physical properties of the mesoscopic assemblages. The predominant method for controlling interfacial tension is the addition of surfactant molecules, which preferentially adsorb onto the interface and modify the interactions between the two phases. Using a model colloidal membrane composed of chiral, rod-like fd-viruses, I will present a new method for controlling interfacial tension which does not require additional surfactant components, but instead utilizes the intrinsic chirality of the constituent rods.
I will demonstrate that chirality can be used to continuously tune the interfacial tension of a membrane and to drive a dramatic phase transition from two-dimensional membranes to one-dimensional twisted ribbons. Using a wide variety of microscopic techniques, this transition is characterized over length-scales, ranging from nanometers to microns. Then, using optical forces we demonstrate that malleable chiral assemblages can easily be moved, stretched, attached to each other, and transformed between multiple polymorphic states, thus enabling precise assembly and sculpting of highly adaptable materials with complex topologies. Finally we show that the interplay between geometrical constrains and chirality lead to two types of new defects.
Contact : sigolene.lecuyer@ujf-grenoble.fr
Discipline évènement : (Physique)
Entité organisatrice : (LIPhy)
Nature évènement : (Séminaire)
Evènement répétitif : (Séminaire Mat. Molle/grise)
Site de l'évènement : Domaine Universitaire de St Martin d’Hères
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