Influence of structural disorder on the elastic, frictional, and electrical properties in functionalized polyaniline thin films at the nanoscale investigated by atomic force microscopy

En De Chu, Hsi Hsien Chiang, Shuei De Huang, Po Yen Chen, Yu Tso Liao, Philip Nathaniel, Chein Chun Han, Fang Yuh Lo, Hsiang Chih Chiu*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

Abstract

We investigated the influence of structural order on the elastic, frictional, and electrical properties of butylthio-functionalized PANI (PANI-SBu) films by atomic force microscopy (AFM)-based techniques, including PeakForce quantitative nanomechanical mapping, friction force microscopy, and conductive AFM. The PANI-SBu films were prepared by the drop-cast method from the solution of PANI-SBu in N-methyl-2-pyrrolidone that was continuously stirred. The PANI-SBu films were fabricated after different solution stirring times. The shear force during the mechanical stir will disentangle the highly-coiled PANI-SBu polymer chains in the solution. Therefore, the polymer chains in solution cast on the substrates will progressively self-assemble into a more organized structure when solvents evaporate, leading to PANI-SBu films with improved structural order. Our AFM studies discovered that more structurally-ordered PANI-SBu films have substantially larger out-of-plane elastic moduli and charge mobility but smaller kinetic friction coefficients. The denser packing of polymer molecules increases film elasticities and promotes chain-to-chain charge transport. In addition, stiffer PANI-SBu film surfaces are more difficult to deform when sheared by the sliding AFM probe, resulting in less energy dissipation during AFM friction measurements. Thus, smaller kinetic friction coefficients were found. Conversely, more structurally-disordered PANI-SBu films have smaller elasticity and charge mobility but larger kinetic friction coefficients. Our results demonstrate that it is possible to manipulate the elastic, frictional, and electrical properties of PANI-SBu films by controlling their structural order, which can be essential for developing polymer-based composite materials and flexible electronic devices.

Original languageEnglish
Pages (from-to)448-458
Number of pages11
JournalInternational Journal of Polymer Analysis and Characterization
Volume28
Issue number5
DOIs
Publication statusPublished - 2023

Keywords

  • Polyaniline
  • atomic force microscopy
  • flexible electronics
  • nanomechanics
  • nanotribology

ASJC Scopus subject areas

  • Analytical Chemistry
  • Chemical Engineering(all)
  • Polymers and Plastics

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