Accession Number : ADA319526

Title :   Ordered Piezoelectric Networks via a Liquid-Crystalline Monomer Strategy: Synthesis of the LC Monomer.

Descriptive Note : Technical rept.,

Corporate Author : CALIFORNIA UNIV BERKELEY DEPT OF CHEMISTRY

Personal Author(s) : Baxter, B. C. ; Gin, D. L.

PDF Url : ADA319526

Report Date : 12 DEC 1996

Pagination or Media Count : 7

Abstract : Piezoelectric materials are used in many technological applications. The physical requirements for piezoelectricity are a high degree of bulk order and a noncentrosymmetric bulk structure. Conventional single crystal piezoceramics possess a high degree of order and long term stability; however, they are brittle and difficult to fabricate. Poled piezoelectric polymers offer ease of fabrication and processing; however, they lack long term thermal and mechanical stability. A new technique is described for synthesizing highly ordered, heavily crosslinked piezolectric networks which offer high order and stability as well as ease of fabrication and processing. Crosslinkable, chiral smectic C liquid-crystalline monomers are used to form a layered noncentrosymmetric phase, which is then oriented by an external electric field to generate a monodomain structure. In situ photopolymerization then forms the final noncentrosymmetric network. The key to the success of this strategy is the design and synthesis of a polymerizable liquid crystal with the correct symmetry and phase properties. In this report, we describe our progress towards such a monomer system.

Descriptors :   *LIQUID CRYSTALS, *PIEZOELECTRIC MATERIALS, *MONOMERS, MECHANICAL PROPERTIES, PHOTOCHEMICAL REACTIONS, SYNTHESIS, PHYSICAL PROPERTIES, MATERIALS, POLYMERS, POLYMERIZATION, SINGLE CRYSTALS, THERMAL STABILITY, ELECTRIC FIELDS, CERAMIC MATERIALS, CROSSLINKING(CHEMISTRY), PIEZOELECTRICITY, EXTERNAL.

Subject Categories : Polymer Chemistry
      Radiation and Nuclear Chemistry
      Ceramics, Refractories and Glass
      Crystallography
      Electricity and Magnetism

Distribution Statement : APPROVED FOR PUBLIC RELEASE