Accession Number : ADA267432


Title :   Electrical Conductivity of Ion Implanted Ladder and Semi-Ladder Polymers


Descriptive Note : Final rept. 1 Nov 1991-31 Dec 1992


Corporate Author : OHIO STATE UNIV COLUMBUS


Personal Author(s) : Epstein, Arthur J


Full Text : https://apps.dtic.mil/dtic/tr/fulltext/u2/a267432.pdf


Report Date : 02 Jul 1993


Pagination or Media Count : 58


Abstract : Aromatic heterocyclic ordered rigid rod, ladder and semi-ladder polymers (including BBL, PBO, PBT, and BBB) combine exceptional high temperature stability with excellent mechanical properties as well as environmental stability. We have continued our systematic study of the electronic, photonic, and environmental properties of the pristine polymer. We have discovered the presence of a significant photoconductivity in PBO and characterized its photoluminescence. Extending our photoinduced absorption spectroscopy studies to the millisecond regime we have found the presence of two weak photoinduced optical absorptions. The difference in behavior as compared to other conjugated polymers likely reflects the increased order in the pristine rigid rod and ladder polymers. We have extended our temperature dependent charge transport (dc conductivity, microwave frequency conductivity and dielectric constant, thermoelectric power, magnetoconductivity and electron spin resonance) studies of the ion implanted polymers as a function of implantation dosage., A nonmetal- to-metal transition is found as a function of increasing dosage (occurring at 4 x 10(exp 16) ions/sq cm). For implanted samples of metallic behavior, a unique transition to a nonmetallic behavior has been discovered at 30K. The origin of this transition is attributed to the opening up of a Coulomb gap.


Descriptors :   *POLYMERS , *PHOTOLUMINESCENCE , *ELECTRICAL CONDUCTIVITY , *PHOTOCONDUCTIVITY , *AROMATIC COMPOUNDS , *ION IMPLANTATION , ELECTRONICS , METALS , OPTICS , TEMPERATURE , MAGNETIC PROPERTIES , PHOTONICS , TRANSITIONS , BENZOXAZOLES , CHARGE TRANSFER , DOSAGE , RESONANCE , CONSTANTS , TRANSPORT PROPERTIES , NONMETALS , NITROGEN , THIAZOLES , BENZIMIDAZOLES , THERMOELECTRICITY , HETEROCYCLIC COMPOUNDS , OPENINGS , HYDROXYL RADICALS , MICROWAVE FREQUENCY , ABSORPTION , SULFUR , POWER , ELECTRON SPIN RESONANCE , DIELECTRICS , HIGH TEMPERATURE , MECHANICAL PROPERTIES , STABILITY , ENVIRONMENTS , SPECTROSCOPY


Subject Categories : Organic Chemistry
      Polymer Chemistry
      Electricity and Magnetism
      Solid State Physics


Distribution Statement : APPROVED FOR PUBLIC RELEASE