Doping dependence of electrical and thermal conductivity of nanoscale polyaniline thin films

Jin, Jiezhu; Wang, Qing; Haque, M. Shamsul

doi:10.1088/0022-3727/43/20/205302

Cited by 42 publications

(33 citation statements)

References 25 publications

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“…These electrons serve as the primary charge carriers for electrical conduction, 1 which makes them suitable for thermoelectric applications. 2,3 The electron delocalization and, hence, the electrical conductivity σ can be further enhanced by doping them with various materials. Since the charge transport of delocalized electrons in an EC polymer has a different mechanism than the free electron drift in metals, their electrical conductivity is only weakly correlated with their thermal conductivity κ.…”

Section: Introductionmentioning

confidence: 99%

“…Hence, while the doping of EC polymers increases σ , it does not significantly influence κ. 2,4 Since the electron contribution to heat conduction is typically insignificant in EC polymers, we only consider the more relevant contribution of phonon transport. Individual polymer chains can have a relatively high phonon thermal conductivity κ p as compared to their bulk amorphous volumes.…”

Section: Introductionmentioning

confidence: 99%

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Modifying thermal transport in electrically conducting polymers: Effects of stretching and combining polymer chains

Pal

Balasubramanian

Puri

2012

The Journal of Chemical Physics

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If their thermal conductivity can be lowered, polyacetylene (PA) and polyaniline(PANI) offer examples of electrically conducting polymers that can have potential use as thermoelectrics. Thermal transport in such polymers is primarily influenced by bonded interactions and chain orientations relative to the direction of heat transfer. We employ molecular dynamics simulations to investigate two mechanisms to control the phonon thermal transport in PANI and PA, namely, (1) mechanical strain and (2) polymer combinations. The molecular configurations of PA and PANI have a significant influence on their thermal transport characteristics. The axial thermal conductivity increases when a polymer is axially stretched but decreases under transverse tension. Since the strain dependence of the thermal conductivity is related to the phonon scattering among neighboring polymer chains, this behavior is examined through Herman's orientation factor that quantifies the degree of chain alignment in a given direction. The conductivity is enhanced as adjacent chains become more aligned along the direction of heat conduction but diminishes when they are orthogonally oriented to it. Physically combining these polymers reduces the thermal conductivity, which reaches a minimum value for a 2:3 PANI/PA chain ratio. If their thermal conductivity can be lowered, polyacetylene (PA) and polyaniline (PANI) offer examples of electrically conducting polymers that can have potential use as thermoelectrics. Thermal transport in such polymers is primarily influenced by bonded interactions and chain orientations relative to the direction of heat transfer. We employ molecular dynamics simulations to investigate two mechanisms to control the phonon thermal transport in PANI and PA, namely, (1) mechanical strain and (2) polymer combinations. The molecular configurations of PA and PANI have a significant influence on their thermal transport characteristics. The axial thermal conductivity increases when a polymer is axially stretched but decreases under transverse tension. Since the strain dependence of the thermal conductivity is related to the phonon scattering among neighboring polymer chains, this behavior is examined through Herman's orientation factor that quantifies the degree of chain alignment in a given direction. The conductivity is enhanced as adjacent chains become more aligned along the direction of heat conduction but diminishes when they are orthogonally oriented to it. Physically combining these polymers reduces the thermal conductivity, which reaches a minimum value for a 2:3 PANI/PA chain ratio.

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Modifying thermal transport in electrically conducting polymers: Effects of stretching and combining polymer chains

Pal

Balasubramanian

Puri

2012

The Journal of Chemical Physics

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“…Among the above polymer Polyanaline (PANI) is superior and widely studied because it offers several advantages such as easy synthesis, inexpensive monomer, low density, reversible redox behavior, variable oxidation and electronic states and tunable morphology. Hence based on these properties PANI-based system in combination with other polymers or nanoparticles can be used in coatings, organic electronics, sensors, batteries and electro-optic devices [47,48]. Conductivity of PANIbased systems can be improved with carbon-based materials like carbon nanotubes, graphene, and C 60 or C 70 fullerenes.…”

Section: Fullerenementioning

confidence: 99%

Exploitation of Carbon Nanotubes in High Performance Polyvinylidene Fluoride Matrix Composite: A Review

Begum

Kausar

Ullah

et al. 2015

Polymer-Plastics Technology and Engineering

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Among nanocarbon filler, carbon nanotubes (CNTs) are considered to be an ideal reinforcement due to their miniscule size, and excellent electrical, thermal, and mechanical properties. However, CNTs can be utilized in polymer nanocomposites only if they are homogenously dispersed into polymer matrices. The multi-walled carbon nanotube (MWCNTs) has been concentrated as reinforcement for an important type of thermoplastic polyvinylidene fluoride (PVDF). This review firstly focuses on CNTs modification both by mechanical methods and chemical functionalization to improve their dispersion. Moreover, processing methods for PVDF/CNTs nanocomposite have been discussed. MWCNTs facilitate the electrical conductivity, thermal, rheological and mechanical properties of PVDF.

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“…This feature, coupled with their low thermal conductivity j, makes them suitable for potential thermoelectric applications. 2,3 The performance of a thermoelectric material is evaluated through its figure of merit ZT that is inversely proportional to j. Strategies to manipulate j facilitate the on demand tuning of ZT.…”

mentioning

confidence: 99%

“…Since electronic motion in EC polymers is different from the free electron drift observed in metals, energy, and charge transport through PANI and PA are only weakly correlated. 2,4 Atomic vibrations (phonons) and interatomic collisions are the major thermal energy carriers in these polymers. Hence, by reducing the phonon contribution to the thermal conductivity j p , j can be lowered considerably, which in turn enhances ZT.…”

mentioning

confidence: 99%

Reducing thermal transport in electrically conducting polymers: Effects of ordered mixing of polymer chains

Pal

Balasubramanian

Puri

2013

Applied Physics Letters

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Reducing the phonon thermal conductivity of electrically conducting polymers can facilitate their use as potential thermoelectric materials. Thus, the influence of the coupling between the longitudinal and transverse phonon modes on overall thermal conductivity is explored for binary mixtures of polyaniline (PANI) and polyacetylene (PA) chains by considering various geometric polymer mixture configurations. The molecular simulations reveal that an increase in the interfacial area available for transverse interactions between dissimilar chains enhances atomic interactions that are orthogonal to the heat transfer direction. As transverse collisions between PA and PANI chains are enhanced, the motion of longitudinal phonons is disrupted, impeding thermal transport. This enhances phonon scattering and reduces longitudinal thermal transport. While there is a nonlinear decrease in the phonon thermal conductivity with increasing interfacial contact area, there is a corresponding linear growth in the nonbonded interaction energies between the different polymers.

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Doping dependence of electrical and thermal conductivity of nanoscale polyaniline thin films

Cited by 42 publications

References 25 publications

Modifying thermal transport in electrically conducting polymers: Effects of stretching and combining polymer chains

Modifying thermal transport in electrically conducting polymers: Effects of stretching and combining polymer chains

Exploitation of Carbon Nanotubes in High Performance Polyvinylidene Fluoride Matrix Composite: A Review

Reducing thermal transport in electrically conducting polymers: Effects of ordered mixing of polymer chains

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