Accession Number : ADA314822

Title :   Bipolar Conducting Polymers: Blends of p-Type Polypyrrole and n-Type Ladder Polymer.

Descriptive Note : Technical rept.,

Corporate Author : ROCHESTER UNIV NY DEPT OF CHEMICAL ENGINEERING

Personal Author(s) : Chen, X. L. ; Jenekhe, Samson A.

PDF Url : ADA314822

Report Date : 09 SEP 1996

Pagination or Media Count : 26

Abstract : Bipolar conducting polymers, in which both hole and electron transport contribute to electronic conductivity, have been explored by chemical template synthesis of p-type polypyrrole (PPy) in the matrix of an n-type conjugated ladder polymer, poly(benzimidazolebenzophenanthroline) (BBL). Transmission electron microscopy images of the conducting polymer blends show that 5-20 nm diameter by 100-180 nm long rodlike PPy particles are randomly and homogeneously distributed in the BBL matrix, with connectivity of the PPy phase occurring at a volume fraction of about 0.17. The volume fraction dependence of conductivity of the BBL/PPy blends did not exhibit a percolation threshold at volume fractions as low as 0.007 nor can it be described by percolation-type effective medium theory. Room temperature conductivities as high as 60-70 S/cm were observed in the blends compared to 2 S/cm in pure PPy. The enhanced conductivity and the non-percolation nature of these blends originate from bipolar charge transport involving both conjugated polymer components of the blends. Existence of the oxidized (p-type) polypyrrole and reduced (n-type) BBL that facilitate bipolar charge transport in these blends was established by cyclic voltammetry.

Descriptors :   *CONDUCTIVITY, *POLYMERS, *BIPOLAR SYSTEMS, THRESHOLD EFFECTS, ELECTRON TRANSPORT, SYNTHESIS(CHEMISTRY), ROOM TEMPERATURE, MIXTURES, ELECTRON MICROSCOPY, PARTICLES, IMAGES, TEMPLATES, PYRROLES, CHARGE TRANSFER, N TYPE SEMICONDUCTORS, VOLTAMMETRY, P TYPE SEMICONDUCTORS, PERCOLATION.

Subject Categories : Polymer Chemistry
      Physical Chemistry
      Electricity and Magnetism
      Optics

Distribution Statement : APPROVED FOR PUBLIC RELEASE