Dielectric relaxation in polymer dispersed liquid crystals

• Grant number: 05/03158-8
• Support Opportunities: Regular Research Grants
• Start date: January 01, 2006
• End date: February 28, 2007
• Field of knowledge: Engineering - Electrical Engineering - Electrical Materials
• Principal Investigator: Marcos Rodrigues Costa
• Grantee: Marcos Rodrigues Costa
• Host Institution: Centro Universitário do Norte Paulista (UNORP). Sociedade Assistencial de Educação e Cultura (SAEC). São José do Rio Preto , SP, Brazil

Abstract

The study accomplished by Costa et al [EESC/USP, 2000]in your doctorate allowed to find physical and electric models that aided excessively in the understanding of the mechanisms of dielectric dispersion involved in the nematic liquid crystals (NLCs) (BDH - chemicals ltda). Besides, the electric models represented in a frequency range wide (0,1Hz to 1E7Hz)contributing for that a new sensor electro-optical of AC alternate electric voltage could be developed. The relevance of the developed work can be proven through important publications [Liquid Crystals/LC, 2001; Molecular Crystals and Liquid Crystals/MCLC, 2003; Transactions on Dielectrics and Electrical Insulation/IEEE, 2005], where has been suggested by refers the extension of this research the other materials. This way, giving continuity the research developed in the doctorate of Costa et al [EESC/USP, 2000], this research will have as principal objective to study the mechanisms of dielectric dispersion present in the polymer dispersed liquid crystals (PDLCs), through mainly of the study your complex dielectric permittivity in the domain of the frequency (DF). The choice of the technology of PDLCs is due the inherent advantages that these present, such as, great obtaining easiness, not to use polarizers (besides expensive, its interrupt great part of the light), and its be built with flexible plastic substrate, once they don't depend on surfaces for the anchoring of the liquid crystal, offering like this the perspective of simple processes and of low cost for the development of the displays, besides new applications, as the intelligent windows, color filters controlled by voltage, sensor electro-optical, among others... (AU)