1D-to-3D transition of phonon heat conduction in polyethylene using molecular dynamics simulations

Henry, Asegun; Chen, Gang; Plimpton, Steven J.; Thompson, Aidan P.

doi:10.1103/physrevb.82.144308

Cited by 109 publications

(116 citation statements)

References 38 publications

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“…Computationally, thermal conductivity for crystalline PE using classical MD simulations was predicted to range from ∼45 [14] to 310 AE 190 W m −1 K −1 [15]. Although these calculations used semiempirical potentials, their results are not expected to be orders of magnitude different than the actual value, and thus our calculated value is at least qualitatively consistent with these results.…”

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confidence: 79%

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Lattice Thermal Conductivity of Polyethylene Molecular Crystals from First-Principles Including Nuclear Quantum Effects

2017

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Molecular crystals such as polyethylene are of intense interest as flexible thermal conductors, yet their intrinsic upper limits of thermal conductivity remain unknown. Here, we report a study of the vibrational properties and lattice thermal conductivity of a polyethylene molecular crystal using an ab initio approach that rigorously incorporates nuclear quantum motion and finite temperature effects. We obtain a thermal conductivity along the chain direction of around 160 W m −1 K −1 at room temperature, providing a firm upper bound for the thermal conductivity of this molecular crystal. Furthermore, we show that the inclusion of quantum nuclear effects significantly impacts the thermal conductivity by altering the phase space for three-phonon scattering. Our computational approach paves the way for ab initio studies and computational material discovery of molecular solids free of any adjustable parameters. DOI: 10.1103/PhysRevLett.119.185901 Polymers have long been of interest for their potential as flexible thermal conductors in applications such as flexible electronics [1][2][3][4]. In bulk form, essentially all polymers are thermal insulators, with a thermal conductivity of less than 1 W m −1 K −1 , due to the random orientation of the molecular chains [5]. However, samples with highly aligned molecular chains may exhibit thermal conductivities as much as 2 orders of magnitude larger. Early work by Choy, Chen, and Luk [6] demonstrated that increasing the crystallinity in polymers drives an increase in thermal conductivity along the direction of the covalently bonded molecular chains. In low-density polyethylene, for instance, they reported increased thermal conductivity along the chain direction from 0.4 to 1.5 W m −1 K −1 when the polymers are stretched by a factor of 5. Other experiments on mechanically stretched bulk polyethylene [7,8] report thermal conductivities as high as ∼42 W m −1 K −1 along the stretching direction due to crystalline alignment of the chains.More recently, Shen et al.[9] reported a high thermal conductivity of around 100 W m −1 K −1 in high-quality ultradrawn polyethylene nanofibers. Wang et al.[10] used an optical method to study heat transport along polymer fibers, reporting thermal conductivity on the order of tens of W m −1 K −1 for polymers such as crystalline polyethylene and poly (p-phenylene benzobisoxazole). Singh et al.[11] reported amorphous aligned polythiophene fibers with a thermal conductivity of around 4 W m −1 K −1 , a factor of 20 increase over that of the unaligned fibers.Despite these experimental advances, the theoretical treatment of heat transport in molecular crystals remains less developed. Molecular dynamics has been used in many studies to examine heat transport in polymers such as stretched polyethylene [12] and polydimethylsiloxane [13]. However, the semiempirical potentials used in these studies restrict their predictive power, especially for the polymers for which experimental data are scarce or unavailable.Additionally, as with covalent crystals,...

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confidence: 79%

“…For instance, reports of thermal conductivity of polyethylene obtained by classical molecular dynamics with different potentials vary from ∼45 [14] to 310 AE 190 W m −1 K −1 [15]. As a result, a rigorous upper bound for the thermal conductivity of molecular crystals such as polyethylene is lacking.…”

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confidence: 99%

Lattice Thermal Conductivity of Polyethylene Molecular Crystals from First-Principles Including Nuclear Quantum Effects

2017

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“…This is because the intermolecular van der Waals interactions with neighboring chains can disrupt the correlation in each chain leading to finite and convergent thermal conductivity 50 . It is conceivable that boundaries (i.e., the chain ends) or other perturbative stimuli such as phonon-photon scattering could disrupt the persistent correlation and cause finite thermal conductivity.…”

Section: Divergent Thermal Conductivity In Polymer Chainsmentioning

confidence: 99%

Understanding Divergent Thermal Conductivity in Single Polythiophene Chains Using Green–Kubo Modal Analysis and Sonification

Winters

DeAngelis

et al. 2017

J. Phys. Chem. A

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Abstract:We used molecular dynamics simulations, the Green-Kubo Modal Analysis (GKMA) method and sonification to study the modal contributions to thermal conductivity in individual polythiophene chains. The simulations suggest that it is possible to achieve divergent thermal conductivity and the GKMA method allowed for exact pinpointing of the modes responsible for the anomalous behavior. The analysis showed that transverse vibrations in the plane of the aromatic rings at low frequencies ~ 0.05 THz are primarily responsible. Further investigation showed that the divergence arises from persistent correlation between the three lowest frequency modes on chains. Sonification of the mode heat fluxes revealed regions where the heat flux amplitude yields a somewhat sinusoidal envelope with a long period similar to the relaxation time. This characteristic in the divergent mode heat fluxes gives rise to the overall thermal conductivity divergence, which strongly supports earlier hypotheses that attribute the divergence to correlated phonon-phonon scattering/interactions. Main text:In all substances, energy/heat is transferred through atomic motions. In electrically conductive materials, electrons can become the primary heat carriers, but in all phases of matter, atomic motions are always present and contribute to the thermal conductivity of every object. Here, we use the term "object" instead of "material" to emphasize that thermal conductivity is highly dependent on the actual structure of an object, that is, its internal atomic level structure and its larger nanoscale or microscale geometry [1][2][3][4][5][6] . In studying the physics of thermal conductivity, tremendous progress has been made over the last 20 years toward understanding various mechanisms that allow one to reduce thermal conductivity in solids 1,7 . This reduction is generally measured relative to a theoretical upper limiting maximum value that arises solely from the intrinsic anharmonicity within the interactions between atoms.In the limiting case, where the atomic interactions are perfectly harmonic, thermal conductivity tends to infinity because the normal modes of vibration do not interact, thus yielding effectively infinite phonon mean free paths and thermal conductivity. As a result, the notion of anharmonicity is critical, and perfectly harmonic interactions between atoms are physically unreasonable. This is because an asymmetry in the energetic well between atoms is an inherent consequence of finite bonding energy (e.g., at some point, the potential energy surface must become concave down). Although one can approach the harmonic limit at cryogenic temperatures, the notion that divergent thermal conductivity (e.g., anomalous thermal conductivity) might be realizable in a real material at room temperature seems theoretically impossible. However, in 1955 Fermi, Pasta, and Ulam (FPU) 8 made a "shocking little discovery" that even an anharmonic system can exhibit infinite thermal conductivity.FPU conducted a numerical experiment with a one-dimensio...

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“…The idea behind this approach is that amorphous polymers consist of long and highly entangled chains whose disordered arrangement prevents the propagation of phonons [1,[31][32][33][34][35][36][37]. However, a stretched polymer chain can be an excellent heat conductor, as phonons can travel along its back-bone unhindered for very long distances [1,11,[38][39][40][41]. According to theoretical simulations the conductivity for some polymers may even diverge to infinity in the limit of an infinitely long chain [1,11,[38][39][40][41].…”

Section: Introductionmentioning

confidence: 99%

“…However, a stretched polymer chain can be an excellent heat conductor, as phonons can travel along its back-bone unhindered for very long distances [1,11,[38][39][40][41]. According to theoretical simulations the conductivity for some polymers may even diverge to infinity in the limit of an infinitely long chain [1,11,[38][39][40][41]. In reality, however, finite chains are expected to always exhibit finite thermal conductivity, but the potential for thermal superconductivity suggests that the polymers chains intrinsically have the ability to conduct heat extremely well, if structured properly.…”

Section: Introductionmentioning

confidence: 99%

Graphite-high density polyethylene laminated composites with high thermal conductivity made by filament winding

Lv¹,

Sultana²,

Rohskopf³

et al. 2018

Express Polym. Lett.

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Abstract.The low thermal conductivity of polymers limits their use in numerous applications, where heat transfer is important. The two primary approaches to overcome this limitation, are to mix in other materials with high thermal conductivity, or mechanically stretch the polymers to increase their intrinsic thermal conductivity. Progress along both of these pathways has been stifled by issues associated with thermal interface resistance and manufacturing scalability respectively. Here, we report a novel polymer composite architecture that is enabled by employing typical composites manufacturing method such as filament winding with the twist that the polymer is in fiber form and the filler in form of sheets. The resulting novel architecture enables accession of the idealized effective medium composite behavior as it minimizes the interfacial resistance. The process results in neat polymer and 50 vol% graphite/polymer plates with thermal conductivity of 42 W·m -1 ·K -1 (similar to steel) and 130 W·m -1 ·K -1 respectively.

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1D-to-3D transition of phonon heat conduction in polyethylene using molecular dynamics simulations

Cited by 109 publications

References 38 publications

Lattice Thermal Conductivity of Polyethylene Molecular Crystals from First-Principles Including Nuclear Quantum Effects

Lattice Thermal Conductivity of Polyethylene Molecular Crystals from First-Principles Including Nuclear Quantum Effects

Understanding Divergent Thermal Conductivity in Single Polythiophene Chains Using Green–Kubo Modal Analysis and Sonification

Graphite-high density polyethylene laminated composites with high thermal conductivity made by filament winding

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