MSE Seminar Series: Eduardo Soto-Bustamonte
Friday, September 12, 2014
Room 2108, Chemical and Nuclear Engineering Bldg.
301 405 5240
From Polar Materials to Polymerizable Liquid Crystals Using Electric Field
Eduardo A. Soto-Bustamonte
Departmento de Química Orgánica y Fisicoquímica
University of Chile, Santiago
In liquid crystals and in general, polymer preparation is usually carried out from radical initiated polymerization outside the electrode or typically UV-light polymerization processes by photo-induced decomposition to generate radicals thus promoting the polymerization inside the cell. Here, we report a new methodology of stabilizing a LC or a mixture of them using ethylenic monomeric materials . The cells are with homogeneous anti-parallel alignment and a thickness which can be varied between 2 and 40 micrometers. Several LC monomers have been submitted to the new electro-polymerization process.
The electro-polymerization process consists in the polymerization of monomeric liquids crystals inside glass cells with ITO electrodes and planar antiparallel alignment treatment. The cell is maintained at a temperature where the material is in the isotropic state and is exposed to a constant DC voltage. The product obtained can be seen as a birefringent material in the electrode area at temperatures where the initial material is in the isotropic state.
The product is a polymer due to its high and diffuse clearing temperature and the intrinsic properties of the new material. MALDI-TOF MS and 1H-NMR spectra confirm that the product is a polymer. The results are concordant with a mechanism where the electrode polarity plays an important role in the polymer formation. The samples also develop bi-layered smectic phases.
A new technology based on liquid crystals is proposed, which considers the use of electric field to promote polymerization and thus obtaining highly ordered systems where guest molecules may change the properties of the formed matrix. This constitutes a major advantage over the current technology, since the polymer process is carried out synergistically aligning the molecules at the same time that polymerization occurs induced by the field.
 M.D.Lechner, K. Gehrke, E.H. Nordmeier, Macromolekulare Chemie, Birkhauser Verlag, 1993.
"In Situ Obtained Polymer Without Using Solvent or Polymerization Initiator; Highly Oriented Polarizer or Pixel; the Apparatus that is Formed with such Polymer and the use Thereof”, Universidad de Chile, sent on 30.01.12, E.A. Soto Bustamante, V.H. Trujillo-Rojo, WO2012CL00002.