par- 22 mai 2012
Jongwook Kim, du laboratoire Physique de la Matière Condensée (Ecole Polytechnique) présentera un séminaire le 7 juin 2012 à 11h00 dans la bibliothèque du laboratoire PECSA (7e étage, bâtiment F, porte 754) intitulé :
Liquid crystalline behaviour of colloidal LaPO4 nanorods suspensions
Mineral liquid crystals (MLC) combine the athermal lyotropic LC behaviour with the intrinsic properties of minerals such as large refractive index and dichroïsm. However, a practical use of such systems has long been limited due to the difficulty in synthesis, stabilization, and control of colloidal behavior of anisotropic mineral nanoparticles. We developed a new MLC system composed of size-tuned LaPO4 nanorods that exhibits highly stabilized isotropic-nematic-columnar mesophases and the controlled transition among them. A remarkable feature of this system is the efficient orientation of nanorods under a low magnitude of electric field associated with a large optical birefringence, i.e., a strong optical Kerr effect, which is promising for a new generation of electro-optical devices. Also, other novel properties such as the fluorescence of the system of doped LaPO4 nanorods are discussed envisaging their application in various fields.
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