Stress and Structure Relaxations in Smectic Liquid Crystal Elastomers

POSTER

Abstract

Randomly oriented smectic domains (polydomain) in liquid crystal elastomer orient under uniaxial stress to form an optically monodomain sample. We studied the dynamics of stress relaxation and how it depends on the changes in microscopic elastomer structural during the polydomain to monodomain (PM) transition by x-ray diffraction. The results of stress relaxation data can be well approximated by a double exponential equation, $\sigma $(t) $=$ $\sigma_{1}$exp(-t/$\tau_{1}) \quad + \quad \sigma_{2}$exp (t/$\tau _{2})$ involving short ($\tau_{1}$ $\sim$ 1 min), and long ($\tau_{2})$ relaxation times. The long relaxation time, $\tau $2 is strain dependent and it decreases exponentially from 18 to 10 min with increasing strain. The structural relaxation is well described by a single exponential function with constant, $\tau_{\alpha }$, which is $\sim$ 45 min in the polydomain region, and $\sim$ 8 min in the monodomain state. The difference between the stress and structural relaxations is attributed to the underlying factors involved during the PM transition. The stress relaxation is associated with the slippage of polymer chains, while structural relaxation is attributed to the rotation of the smectic domains.

Authors

  • Dena Mae Agra-Kooijman

    Kent State University

  • Michael Fisch

    Kent State University

  • Frazier Baker

    Youngstown State University, Kent State University, Liquid Crystal Institute, Kent State University, Department of Biological Sciences, Kent State University, Department of Physics, Department of Chemistry and Biochemistry, Kent State University, Stony Brook Univ, Ohio Univ, Institute for Advanced Simulation, Institut fur Kernphysik, and Julich Center, Bowling Green State University, Dept. of Physics, Hiram College, Ohio State Univ - Columbus, Kent State University, Psychology Dept, Cleveland State University, Physics Dept, Cleveland State University, Chemical Physics Interdisciplinary Program and Liquid Crystal Institute, Kent State University, Kent, OH 44242-0001, USA, Univ of Konstanz, Univ College London, NIST, Hiroshima Univ, KIT, Missouri University of Science and Technology, University of California, San Diego, Georgia Institute of Technology, KSU, SKKU, Lock Haven Univ, Massachusetts General Hospital, University of Science and Technology of China, Yale University, Shanghai Institute of Microsystem and Information Technology, CAS, Nanjing University, Liquid Crystal Institute and Chemical Physics Interdisciplinary Program, Kent State University, Kent, OH 44242, USA, Department of Physics, Kent State University, Kent OH 44242, Department of Electro-Optic Engineering Ilse Katz Institute for Nanoscale Science and Technology Ben Gurion University, Beer Sheva 84105, Israel, Ohio University Zanesville

  • Frazier Baker

    Youngstown State University, Kent State University, Liquid Crystal Institute, Kent State University, Department of Biological Sciences, Kent State University, Department of Physics, Department of Chemistry and Biochemistry, Kent State University, Stony Brook Univ, Ohio Univ, Institute for Advanced Simulation, Institut fur Kernphysik, and Julich Center, Bowling Green State University, Dept. of Physics, Hiram College, Ohio State Univ - Columbus, Kent State University, Psychology Dept, Cleveland State University, Physics Dept, Cleveland State University, Chemical Physics Interdisciplinary Program and Liquid Crystal Institute, Kent State University, Kent, OH 44242-0001, USA, Univ of Konstanz, Univ College London, NIST, Hiroshima Univ, KIT, Missouri University of Science and Technology, University of California, San Diego, Georgia Institute of Technology, KSU, SKKU, Lock Haven Univ, Massachusetts General Hospital, University of Science and Technology of China, Yale University, Shanghai Institute of Microsystem and Information Technology, CAS, Nanjing University, Liquid Crystal Institute and Chemical Physics Interdisciplinary Program, Kent State University, Kent, OH 44242, USA, Department of Physics, Kent State University, Kent OH 44242, Department of Electro-Optic Engineering Ilse Katz Institute for Nanoscale Science and Technology Ben Gurion University, Beer Sheva 84105, Israel, Ohio University Zanesville

  • Frazier Baker

    Youngstown State University, Kent State University, Liquid Crystal Institute, Kent State University, Department of Biological Sciences, Kent State University, Department of Physics, Department of Chemistry and Biochemistry, Kent State University, Stony Brook Univ, Ohio Univ, Institute for Advanced Simulation, Institut fur Kernphysik, and Julich Center, Bowling Green State University, Dept. of Physics, Hiram College, Ohio State Univ - Columbus, Kent State University, Psychology Dept, Cleveland State University, Physics Dept, Cleveland State University, Chemical Physics Interdisciplinary Program and Liquid Crystal Institute, Kent State University, Kent, OH 44242-0001, USA, Univ of Konstanz, Univ College London, NIST, Hiroshima Univ, KIT, Missouri University of Science and Technology, University of California, San Diego, Georgia Institute of Technology, KSU, SKKU, Lock Haven Univ, Massachusetts General Hospital, University of Science and Technology of China, Yale University, Shanghai Institute of Microsystem and Information Technology, CAS, Nanjing University, Liquid Crystal Institute and Chemical Physics Interdisciplinary Program, Kent State University, Kent, OH 44242, USA, Department of Physics, Kent State University, Kent OH 44242, Department of Electro-Optic Engineering Ilse Katz Institute for Nanoscale Science and Technology Ben Gurion University, Beer Sheva 84105, Israel, Ohio University Zanesville

  • Frazier Baker

    Youngstown State University, Kent State University, Liquid Crystal Institute, Kent State University, Department of Biological Sciences, Kent State University, Department of Physics, Department of Chemistry and Biochemistry, Kent State University, Stony Brook Univ, Ohio Univ, Institute for Advanced Simulation, Institut fur Kernphysik, and Julich Center, Bowling Green State University, Dept. of Physics, Hiram College, Ohio State Univ - Columbus, Kent State University, Psychology Dept, Cleveland State University, Physics Dept, Cleveland State University, Chemical Physics Interdisciplinary Program and Liquid Crystal Institute, Kent State University, Kent, OH 44242-0001, USA, Univ of Konstanz, Univ College London, NIST, Hiroshima Univ, KIT, Missouri University of Science and Technology, University of California, San Diego, Georgia Institute of Technology, KSU, SKKU, Lock Haven Univ, Massachusetts General Hospital, University of Science and Technology of China, Yale University, Shanghai Institute of Microsystem and Information Technology, CAS, Nanjing University, Liquid Crystal Institute and Chemical Physics Interdisciplinary Program, Kent State University, Kent, OH 44242, USA, Department of Physics, Kent State University, Kent OH 44242, Department of Electro-Optic Engineering Ilse Katz Institute for Nanoscale Science and Technology Ben Gurion University, Beer Sheva 84105, Israel, Ohio University Zanesville