Constant Voltage Conductivity Measurements of a Critical Temperature Transition in Low Density Polyethylene

ORAL

Abstract

Temperature-dependent constant voltage conductivity measurements of the highly disordered insulating polymeric material low density polyethylene (LDPE) were made to investigate a transition of electrical transport mechanisms from variable range hopping to multiple trapping at a critical temperature. Such a transition is evidenced as a change of slope in a double logarithmic plot of conductivity versus temperature at the critical temperature, $T_{c}$. Below $T_{c}$ variable range hopping, with a T$^{\mathrm{-1/4}}$ dependence, is the dominant mechanism; above $T_{c}$ multiple trapping mechanisms, with linear T$^{\mathrm{-1}}$ dependence dominate. To investigate this transition, the sample temperature, $T$, was varied from \textasciitilde 230 K to 300 K, based on prior experimental evidence which estimated $T_{c}$ to be \textasciitilde 268 K, along with theoretical models which predict $T_{c}_{\mathrm{\thinspace }}$\textasciitilde 255 K. A constant voltage conductivity system was used, with current measured in parallel plate geometry with a steady voltage applied across 25 \textmu m thin film LDPE samples using Ohm's law. Experiments were conducted \textit{in vaccu}, with a lower bound in measurable conductivities of \textasciitilde 1$\cdot $10$^{\mathrm{-21}}$ ($\Omega $-cm)$^{\mathrm{-1}}$ due to fA current resolution. Transitions seen in other electron transport measurements and related structural phase transitions at comparable temperatures are discussed.

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Authors

  • Megan Loveland

    Utah State University

  • John Spence

    Brigham Young University, Department of Physics and Astronomy, University of New Mexico, Albuquerque, NM 87131, Department of Scientific Research, The Metropolitan Museum of Art, New York, NY 10028, Century Darkroom, Toronto, ON M4M 2S1, Canada, Colorado State University, University of Waterloo, Southern Connecticut State University, Clemson University, Oak Ridge National Laboratory, University of Bordeaux, BYU REU Program, New Mexico State University, Arizona State University, Biodesign Institute, Center for Applied Structural Discovery, University of Utah, University of Hawaii, Johns Hopkins University, Embry-Riddle Aeronautical University, Arizona State University, Utah State University, Department of Physics, United States Air Force Academy, Department of Chemistry, Case Western Reserve University, Air Force Research Laboratory, Wright-Patterson Air Force Base, United States Air Force Academy, Lousiana State University, Brigham Young University - Provo, The University of New Mexico, Department of Physics and Astronomy, Brigham Young University, SLAC National Accelerator Laboratory, Department of Chemistry, Brigham Young University, Department of Materials, Devices, and Energy Technologies, Sandia National Laboratories, Albuquerque, New Mexico 87185, USA, Department of Physics, New Mexico State University, Las Cruces, New Mexico 88003, USA, Center for Memory and Recording research, UCSD, Advanced Photon Source, Argonne National Laboratory, University of New Mexico, Los Alamos National Laboratory, University of Chicago

  • John Spence

    Brigham Young University, Department of Physics and Astronomy, University of New Mexico, Albuquerque, NM 87131, Department of Scientific Research, The Metropolitan Museum of Art, New York, NY 10028, Century Darkroom, Toronto, ON M4M 2S1, Canada, Colorado State University, University of Waterloo, Southern Connecticut State University, Clemson University, Oak Ridge National Laboratory, University of Bordeaux, BYU REU Program, New Mexico State University, Arizona State University, Biodesign Institute, Center for Applied Structural Discovery, University of Utah, University of Hawaii, Johns Hopkins University, Embry-Riddle Aeronautical University, Arizona State University, Utah State University, Department of Physics, United States Air Force Academy, Department of Chemistry, Case Western Reserve University, Air Force Research Laboratory, Wright-Patterson Air Force Base, United States Air Force Academy, Lousiana State University, Brigham Young University - Provo, The University of New Mexico, Department of Physics and Astronomy, Brigham Young University, SLAC National Accelerator Laboratory, Department of Chemistry, Brigham Young University, Department of Materials, Devices, and Energy Technologies, Sandia National Laboratories, Albuquerque, New Mexico 87185, USA, Department of Physics, New Mexico State University, Las Cruces, New Mexico 88003, USA, Center for Memory and Recording research, UCSD, Advanced Photon Source, Argonne National Laboratory, University of New Mexico, Los Alamos National Laboratory, University of Chicago

  • John Spence

    Brigham Young University, Department of Physics and Astronomy, University of New Mexico, Albuquerque, NM 87131, Department of Scientific Research, The Metropolitan Museum of Art, New York, NY 10028, Century Darkroom, Toronto, ON M4M 2S1, Canada, Colorado State University, University of Waterloo, Southern Connecticut State University, Clemson University, Oak Ridge National Laboratory, University of Bordeaux, BYU REU Program, New Mexico State University, Arizona State University, Biodesign Institute, Center for Applied Structural Discovery, University of Utah, University of Hawaii, Johns Hopkins University, Embry-Riddle Aeronautical University, Arizona State University, Utah State University, Department of Physics, United States Air Force Academy, Department of Chemistry, Case Western Reserve University, Air Force Research Laboratory, Wright-Patterson Air Force Base, United States Air Force Academy, Lousiana State University, Brigham Young University - Provo, The University of New Mexico, Department of Physics and Astronomy, Brigham Young University, SLAC National Accelerator Laboratory, Department of Chemistry, Brigham Young University, Department of Materials, Devices, and Energy Technologies, Sandia National Laboratories, Albuquerque, New Mexico 87185, USA, Department of Physics, New Mexico State University, Las Cruces, New Mexico 88003, USA, Center for Memory and Recording research, UCSD, Advanced Photon Source, Argonne National Laboratory, University of New Mexico, Los Alamos National Laboratory, University of Chicago