Jon Otto Fossum de la Norwegian University of Science and Technology (NTNU), actuellement chercheur invité à l’institut Pierre-Gilles de Gennes, présentera mercredi 9 novembre à 14h, dans la salle 103 tour 32/42 1er étage, un séminaire intitulé :
Self-assembly of jammed heterogeneous colloidal shells by combining electrohydrodynamics and dielectrophoresis
Résumé
Adsorption and assembly of colloidal particles (such as clay particles) at the surface of liquid droplets are at the base of particle-stabilized emulsions and templating. It has been demonstrated that electrohydrodynamic and dielectrophoretic effects in leaky-dielectric liquid drops can be used to structure and dynamically control colloidal particle assemblies at drop surfaces [1], suggesting new routes for Janus or patchy colloidosome assembly, including jammed colloidal shells(Pickering drops) with designed heterogeneous surfaces that combine the functionalities offered by Janus or patchy particles, and those given by permeable shells such as colloidosomes[2]. It has also been demonstrated that the stress induced by uniform electric-fields in colloidal jammed Pickering drops, is absorbed by plastic deformation or surface crumpling, at electric fields above a yield stress. At stronger electric fields, simultaneous deformation and spontaneous electrohydrodynamic rotation of Pickering drops has been observed, followed by a transition from a solid to a liquid state and tank-treading dynamics of the Pickering particle layer [3].
1. Dommersnes P., Rozynek Z., Mikkelsen M., Castberg R. , Kjerstad, K., Hersvik K., Fossum J.O. (2013) Active structuring of colloidal armour on liquid drops, Nature Communications 4:2066
2. Rozynek Z., Mikkelsen A., Dommersnes P., Fossum J.O. (2014), Electroformation of Janus and patchy capsules, Nature Communications, 5:3945
3. A. Mikkelsen, P. Dommersnes, Z. Rozynek, A. Gholamipour-Shirazi, M. S. Carvalho and J.O. Fossum (2016) Mechanics and rheology of Pickering drops probed by electric field induced stress, In preparation for submission
