The Effect of a Nematic Liquid Crystal Environment on the Alignment of the Conductive polymer MEH-PPV as a Function of Polymer Chain Length

ORAL

Abstract

MEH-PPV (poly(2-methoxy, 5 ethyl (2' hexyloxy) para-phenylene vinylene)) is a conductive, highly fluorescent polymer that has important technological applications in photovoltaic devices such as organic solar cells and light emitting diodes. It is known that the polymer conformation can be controlled through the environment in which it is present. By using a nematic liquid crystal solvent, 5CB (4-pentyl-4'-cyanobiphenyl) as a host for the MEH-PPV, we are able to stretch and align the polymer chains along the liquid crystal director to a much greater extent than it is possible in an isotropic solvent. We use single molecule polarization spectroscopy to determine the solute order parameter for the MEH-PPV -- 5CB solute-solvent system. Using MEH-PPV samples with different molecular weights, we are able to investigate the dependence of the solute order parameter on the polymer chain length. We observe a decrease in order parameter for shorter polymer chains with the solute order parameter equaling that of the solvent for a single molecule solute (rhodamine 6G).

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Authors

  • David Solis

    University of Dallas

  • Edward Fry

    Institute for Astronomy, ETH, National Optical Astronomy Observatory, Department of Physics, ETH, Texas A&M University, LANL, American Physical Society, Society of Physics Students National Office, Texas Tech University, University of Texas, Universite d'Orleans, Steward Observatory, University of Arizona, Texas A\&M University-Commerce, Texas A\&M University, Institute for Quantum Electronics, ETH Zurich, Department of Engineering and Applied Science, Harvard University, Rice University, University of Houston, Bucknell University, Department of Physics, Texas A\&M University, Air Force Research Laboratory, Department of Physics, Texas A\&M University, College Station, TX 77843, Department of Physics and MIC, Texas A\&M University, University of Texas at Arlington, Changwon National University, University of North Texas, Southwestern University, The Pennsylvania State University, University of Dallas, UT Southwestern Medical Center, Naval Air Systems Command, Institute for Quantum Studies and Department of Physics, Texas A\&M University, College Station, TX 77843, The University of Texas at Arlington, TCU, ELTE, National Institute of Chemistry, Ljubljana, Slovenia, Texas Christian University, Fort Worth, TX, Dept. of Physics, Texas A\&M University-Commerce, Univ. of North Texas, Los Alamos National Laboratory, Oswego State University of New York, Lee College, University of Texas at San Antonio, UTSA-Professor, UNT, Sam Houston State University, Sewanee: The University of the South, Director of Education for NSF, Center for Nonlinear Dynamics and Department of Physics, The University of Texas at Austin, Sackler School of Chemistry, Tel-Aviv University, Rice University, Department of Physics and Astronomy, Houston, TX 77005, Center for Nonlinear Dynamics, University of Texas at Austin

  • Andrew Tangonan

  • Edward Fry

    Institute for Astronomy, ETH, National Optical Astronomy Observatory, Department of Physics, ETH, Texas A&M University, LANL, American Physical Society, Society of Physics Students National Office, Texas Tech University, University of Texas, Universite d'Orleans, Steward Observatory, University of Arizona, Texas A\&M University-Commerce, Texas A\&M University, Institute for Quantum Electronics, ETH Zurich, Department of Engineering and Applied Science, Harvard University, Rice University, University of Houston, Bucknell University, Department of Physics, Texas A\&M University, Air Force Research Laboratory, Department of Physics, Texas A\&M University, College Station, TX 77843, Department of Physics and MIC, Texas A\&M University, University of Texas at Arlington, Changwon National University, University of North Texas, Southwestern University, The Pennsylvania State University, University of Dallas, UT Southwestern Medical Center, Naval Air Systems Command, Institute for Quantum Studies and Department of Physics, Texas A\&M University, College Station, TX 77843, The University of Texas at Arlington, TCU, ELTE, National Institute of Chemistry, Ljubljana, Slovenia, Texas Christian University, Fort Worth, TX, Dept. of Physics, Texas A\&M University-Commerce, Univ. of North Texas, Los Alamos National Laboratory, Oswego State University of New York, Lee College, University of Texas at San Antonio, UTSA-Professor, UNT, Sam Houston State University, Sewanee: The University of the South, Director of Education for NSF, Center for Nonlinear Dynamics and Department of Physics, The University of Texas at Austin, Sackler School of Chemistry, Tel-Aviv University, Rice University, Department of Physics and Astronomy, Houston, TX 77005, Center for Nonlinear Dynamics, University of Texas at Austin

  • Edward Fry

    Institute for Astronomy, ETH, National Optical Astronomy Observatory, Department of Physics, ETH, Texas A&M University, LANL, American Physical Society, Society of Physics Students National Office, Texas Tech University, University of Texas, Universite d'Orleans, Steward Observatory, University of Arizona, Texas A\&M University-Commerce, Texas A\&M University, Institute for Quantum Electronics, ETH Zurich, Department of Engineering and Applied Science, Harvard University, Rice University, University of Houston, Bucknell University, Department of Physics, Texas A\&M University, Air Force Research Laboratory, Department of Physics, Texas A\&M University, College Station, TX 77843, Department of Physics and MIC, Texas A\&M University, University of Texas at Arlington, Changwon National University, University of North Texas, Southwestern University, The Pennsylvania State University, University of Dallas, UT Southwestern Medical Center, Naval Air Systems Command, Institute for Quantum Studies and Department of Physics, Texas A\&M University, College Station, TX 77843, The University of Texas at Arlington, TCU, ELTE, National Institute of Chemistry, Ljubljana, Slovenia, Texas Christian University, Fort Worth, TX, Dept. of Physics, Texas A\&M University-Commerce, Univ. of North Texas, Los Alamos National Laboratory, Oswego State University of New York, Lee College, University of Texas at San Antonio, UTSA-Professor, UNT, Sam Houston State University, Sewanee: The University of the South, Director of Education for NSF, Center for Nonlinear Dynamics and Department of Physics, The University of Texas at Austin, Sackler School of Chemistry, Tel-Aviv University, Rice University, Department of Physics and Astronomy, Houston, TX 77005, Center for Nonlinear Dynamics, University of Texas at Austin