Affiliations 

  • 1 †Department of Physics and Mathematics, University of Hull, Hull, United Kingdom HU6 7RX
  • 2 ‡TE Connectivity, Menlo Park, California 94025, United States
  • 3 §Department of Physics, National Technical University of Athens, 15780 Zografou, Greece
Langmuir, 2015 Jun 9;31(22):6253-64.
PMID: 25996202 DOI: 10.1021/acs.langmuir.5b00686

Abstract

Surface interface engineering using superhydrophobic gold electrodes made with 1-dodecanethiol self-assembled monolayer (SAM) has been used to enhance the current limiting properties of novel surge protection devices based on the intrinsic conducting polymer, polyaniline doped with methanesulfonic acid. The resulting devices show significantly enhanced current limiting characteristics, including current saturation, foldback, and negative differential effects. We show how SAM modification changes the morphology of the polymer film directly adjacent to the electrodes, leading to the formation of an interfacial compact thin film that lowers the contact resistance at the Au-polymer interface. We attribute the enhanced current limiting properties of the devices to a combination of lower contact resistance and increased Joule heating within this interface region which during a current surge produces a current blocking resistive barrier due to a thermally induced dedoping effect caused by the rapid diffusion of moisture away from this region. The effect is exacerbated at higher applied voltages as the higher temperature leads to stronger depletion of charge carriers in this region, resulting in a negative differential resistance effect.

* Title and MeSH Headings from MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.