Article
Physics, Multidisciplinary
Hao Feng, Kai Zhang, Xin Wang, Guiqing Zhang, Xiaoyong Guo
Summary: In this paper, the thermal transport of bilayer graphene is revisited using the HNEMD method. The results show that the thermal conductivity of bilayer graphene is reduced by phonon scattering among graphene layers, and a new phonon mode is discovered which may have a negative contribution to the thermal conductivity.
Article
Nanoscience & Nanotechnology
Haikuan Dong, Zheyong Fan, Ping Qian, Yanjing Su
Summary: This study establishes the exact equivalence between equilibrium molecular dynamics (EMD) and nonequilibrium molecular dynamics (NEMD) in thermal conductivity calculations.
PHYSICA E-LOW-DIMENSIONAL SYSTEMS & NANOSTRUCTURES
(2022)
Article
Biochemistry & Molecular Biology
Bingxian Ou, Junxia Yan, Qinsheng Wang, Lixin Lu
Summary: In titanium-based metal-matrix composites (MMCs), the addition of graphene as a filler can enhance thermal conductivity. Through classical molecular dynamics simulations, we explored the thermal conductance at the titanium-graphene interface and found that the thermal boundary conductance decreases with an increasing layer number, decreases under tensile strain, and increases with compressive strain.
Article
Thermodynamics
Shuyi He, Hanli Shi, Lijuan Gong, Jie Yang, Qingzhen Han, Yuehong Ren, Zhaotan Jiang
Summary: The thermal conductivity of quasi-bilayer graphene is found to increase with the increase of its dimensions and decrease with the increase of layer number. The presence of perfluorophenylazide molecules suppresses the thermal conductivity, but it can still be a feasible way to fabricate high-quality graphene-based films.
NUMERICAL HEAT TRANSFER PART A-APPLICATIONS
(2023)
Article
Materials Science, Multidisciplinary
Yongfeng Qu, Jin Yuan, Ningkang Deng, Wenbo Hu, Shengli Wu, Hongxing Wang
Summary: The impact of amorphous silicon (a-Si) intermediate layer thickness on thermal transport at the Si/diamond heterointerface was investigated through molecular dynamics simulations. It was observed that introducing a 0.5-nm-thick a-Si intermediate layer increased the thermal boundary conductance (TBC) by over 38% compared to the Si/diamond interface without the a-Si layer. However, as the thickness of the a-Si layer increased, the TBC of Si/diamond decreased. Analysis of the phonon vibrational spectrum revealed that the a-Si layer alleviated phonon mismatch between Si and diamond, enhancing heat transport channels and leading to increased TBC. Additionally, TBC increased with temperature due to enhanced inelastic scattering of phonons. These findings demonstrate the effective regulation of thermal transport at the Si/diamond heterointerface through control of the a-Si intermediate layer thickness, providing insights for thermal management design in Si/diamond-based electronic devices.
RESULTS IN PHYSICS
(2023)
Article
Materials Science, Multidisciplinary
Alexander J. Gabourie, Saurabh Suryavanshi, Amir Barati Farimani, Eric Pop
Summary: The thermal conductivity of monolayer MoS(2) significantly decreases when supported by SiO2 or encased in SiO(2), while that of bilayer MoS(2) is less affected. These effects are attributed to phonon scattering with remote vibrational modes of the substrate, which are partly screened in bilayer MoS2. This study also reveals that the substrate reduces the dependence of thermal conductivity on temperature and defect densities in monolayer MoS(2).
Article
Nanoscience & Nanotechnology
Prabudhya Roy Chowdhury, Jingjing Shi, Tianli Feng, Xiulin Ruan
Summary: Bismuth telluride (Bi2Te3) and its alloys with antimony telluride (Sb2Te3) are known as the best thermoelectric materials at room temperature. Recent studies have shown high thermoelectric performance in Bi2Te3-Sb2Te3 nanostructures, but computational studies on phonon transport across these nanostructures are limited.
ACS APPLIED MATERIALS & INTERFACES
(2021)
Article
Chemistry, Physical
Anze Hubma, Franci Merzel
Summary: This article presents a new method for efficiently and accurately determining thermal conductivity in liquids. The method combines analytical solutions based on Fourier's law and nonequilibrium MD simulations to find the optimal agreement. The applicability of this method is demonstrated using liquid argon and two water models.
JOURNAL OF MOLECULAR LIQUIDS
(2023)
Article
Thermodynamics
Yang Ming, Zhang Xingli, Zhang Hang
Summary: Through non-equilibrium molecular dynamics simulations, it was found that monovacancy defects significantly affect the thermal conductivity of bilayer graphene nanoribbons, decreasing linearly with the increase of monovacancy concentration and exhibiting a varying trend with temperature. Additionally, a higher thermal conductivity of BGNs is observed when there is a larger difference in monovacancy density between two layers, which suggests potential applications in thermal management through defect engineering.
JOURNAL OF THERMAL SCIENCE
(2021)
Article
Thermodynamics
Penghua Ying, Ting Liang, Ke Xu, Jianbin Xu, Zheyong Fan, Tapio Ala-Nissila, Zheng Zhong
Summary: In this paper, an efficient machine-learned neuroevolution potential model is developed to study the thermal transport in three allotropes of phosphorus. The thermal conductivity values of these allotropes are predicted using molecular dynamics simulations, and the underlying reasons for their significantly different thermal conductivity values are revealed through spectral decomposition, phonon eigenmodes, and phonon participation ratio.
INTERNATIONAL JOURNAL OF HEAT AND MASS TRANSFER
(2023)
Article
Chemistry, Physical
Zequn Wang, Meng An, Kunliang Zhang, Dongsheng Chen, Xuhui Sun, Xin Wang, Yuejin Yuan, Junwen Shi, Jianchun Wu
Summary: Developing semiconducting materials with suitable band gap for next-generation electronic devices has become a hot research topic. The newly synthesized monolayer carbon boron (C3B) material, with outstanding electronic properties and indirect bandgap, shows promise as an alternative to graphene. This study investigates the thermal conductivity of monolayer C3B and graphene, as well as interfacial phonon transport across heterointerfaces. The reduced thermal conductivity of C3B compared to graphene is attributed to the decreased phonon group velocity and phonon relaxation time caused by the introduction of periodic boron atoms in the C3B sheet. The study also discusses the influences of temperature and strain on the thermal conductivity of C3B, and analyzes the thermal transport across graphene|C3B heterointerfaces at different temperatures. These findings provide insights for understanding the thermal transport properties of two-dimensional materials and have potential implications for the design of thermal management and thermoelectric materials.
SURFACES AND INTERFACES
(2023)
Article
Thermodynamics
Ankur Chaurasia, Avinash Parashar
Summary: This study investigates the effect of hexagonal boron nitride nanosheets on the thermal transport properties of high density polyethylene based nanocomposites using experimental and atomistic simulation approaches. The results show that adding boron nitride nanosheets can improve the thermal conductivity of polyethylene, with bi-crystalline BNNS demonstrating superior reinforcing capabilities.
INTERNATIONAL JOURNAL OF HEAT AND MASS TRANSFER
(2021)
Article
Thermodynamics
Andrey Pereverzev, Tommy Sewell
Summary: The Green-Kubo and Helfand moment approaches were used to obtain the thermal conductivity tensor of beta-HMX from MD simulations. The Green-Kubo formula showed slow convergence, but a numerical procedure involving heat current filtering was developed to improve convergence. The Helfand moment approach yielded similar results.
INTERNATIONAL JOURNAL OF HEAT AND MASS TRANSFER
(2022)
Article
Thermodynamics
Lei Xian, Zhengyan Li, Shuchang Li, Lei Chen, Wen-Quan Tao
Summary: The impact of water content and temperature on the thermal conductivity of Nafion membranes was investigated using molecular dynamics simulations. The study reveals that water content mainly positively affects thermal conductivity due to the triple effect of hydrogen bonding, stronger microphase separation, and decreased chain torsion. The study also emphasizes the crucial paths in which hydrogen bonding improves interchain heat transport. Temperature has little and slightly negative effects on thermal conductivity at low and high hydration levels, respectively, due to the influence on hydrogen bonding network and bridging effect. This study expands the design basis of high temperature polymer electrolyte membranes.
INTERNATIONAL JOURNAL OF HEAT AND MASS TRANSFER
(2023)
Article
Chemistry, Physical
Rafat Mohammadi, Mohammad Reza Ghaderi, Ebrahim Hajian
Summary: This study investigates the thermal conductivity of bilayer graphene using non-equilibrium molecular dynamics. The results show that the in-plane thermal conductivity of bilayer graphene with zigzag edges is higher than that of bilayer graphene with armchair edges, and it decreases with increasing temperature and strain. Additionally, the cross-plane thermal conductivity of bilayer graphene is significantly lower than the in-plane results and decreases with increasing temperature.
Article
Chemistry, Physical
Yutaka Oya, Masahiro Nakazawa, Keiichi Shirasu, Yuki Hino, Kyosuke Inuyama, Gota Kikugawa, Jing Li, Riichi Kuwahara, Naoki Kishimoto, Hiroki Waizumi, Masaaki Nishikawa, Anthony Waas, Nobuyuki Odagiri, Andrew Koyanagi, Marco Salviato, Tomonaga Okabe
Summary: By coupling quantum chemical calculations with molecular dynamics simulations, the curing process of epoxy resin can be accurately predicted with minimal artificial parameters. Experimental and simulation results demonstrate that base resin with multi-functional reaction groups can enhance the glass-transition temperature and Young's modulus.
CHEMICAL PHYSICS LETTERS
(2021)
Article
Mechanics
Hiroki Yamaguchi, Gota Kikugawa
Summary: This research studied thermal transpiration flow through a two-dimensional channel with nanoscale clearance using the molecular dynamics method, adopting two Knudsen number conditions by changing the width of the computational cell. The results showed that thermal transpiration flow can occur even under dense gas conditions, inducing flow in the adsorption layer of gas molecules on the channel wall in the height direction.
Article
Chemistry, Physical
Leton C. Saha, Gota Kikugawa
Summary: This study used molecular dynamics simulation to investigate the interfacial heat condition between a PEG self-assembled monolayer and water. The results showed that the thermal boundary conductance of the PEG SAM is higher than that of the alkane-based SAM traditionally used. Structural properties of the PEG SAM were found to greatly influence the TBC of the interface, rather than vibrational properties matching between SAM terminal and water.
JOURNAL OF PHYSICAL CHEMISTRY B
(2021)
Article
Chemistry, Physical
Takamasa Saito, Eita Shoji, Masaki Kubo, Takao Tsukada, Gota Kikugawa, Donatas Surblys
Summary: This study evaluated the affinity between a surface-modified inorganic solid and an organic solvent by calculating the work of adhesion at the interface. Results showed that the surface coverage of the modifier affected the work of adhesion, with solvent molecules penetrating the modification layer at high coverage, increasing the adhesion.
JOURNAL OF CHEMICAL PHYSICS
(2021)
Correction
Chemistry, Physical
Takamasa Saito, Eita Shoji, Masaki Kubo, Takao Tsukada, Gota Kikugawa, Donatas Surblys
JOURNAL OF CHEMICAL PHYSICS
(2021)
Article
Engineering, Multidisciplinary
Xiaoxin Yan, Haibo Zhao, Yanhui Feng, Lin Qiu, Lin Lin, Xinxin Zhang, Taku Ohara
Summary: The study introduced a novel erythritol/graphene composite phase change material, which was found to enhance thermal conductivity and reduce supercooling degree. By adjusting the mass fraction, size, and number of layers of graphene, the melting point of erythritol can be effectively controlled, providing guidance for the design and application of erythritol-based composite phase change materials.
COMPOSITES PART B-ENGINEERING
(2022)
Article
Physics, Applied
Donatas Surblys, Hiroki Matsubara, Gota Kikugawa, Taku Ohara
Summary: This study investigates the reliable computation of heat flux for systems with constraint or rigid body dynamics using the centroid atomic stress form, demonstrating its effectiveness in flexible, semi-flexible, and rigid water models. The contribution of constraint forces to heat flux and thermal conductivity is found to be small but non-negligible, with the centroid formulation producing correct results compared to the original group formulation.
JOURNAL OF APPLIED PHYSICS
(2021)
Article
Chemistry, Physical
Hiroki Matsubara, Donatas Surblys, Yunhao Bao, Taku Ohara
Summary: In this study, non-equilibrium molecular dynamics simulation was used to investigate the effect of surfactants on interfacial thermal transport at solid-liquid interfaces. It was found that interfacial thermal resistance can be minimized by optimizing the vibrational characteristics of surfactant molecules.
JOURNAL OF MOLECULAR LIQUIDS
(2022)
Article
Chemistry, Physical
Yinbo Zhao, Gota Kikugawa, Yoshiaki Kawagoe, Keiichi Shirasu, Naoki Kishimoto, Yingxiao Xi, Tomonaga Okabe
Summary: This study developed a new algorithm that combines distance-based and kinetic criteria to study the cross-linking process of epoxy resins. Using the large-scale atomic/molecular massively parallel simulator (LAMMPS), the effect of model size on the thermomechanical properties of epoxy resins was investigated, providing general guidelines for simulation system size and procedures.
JOURNAL OF PHYSICAL CHEMISTRY B
(2022)
Article
Chemistry, Physical
Donatas Surblys, Florian Mueller-Plathe, Taku Ohara
Summary: Recently, a new method has been developed to calculate the work of adhesion of solid-liquid interfaces using molecular dynamics and thermodynamic integration. However, when there are long-range Coulombic interactions in the interface, special treatment is required. In this study, the researchers replaced the long-range Coulombic interactions with damped Coulomb interactions and explored several thermal integration paths. They found that regardless of the integration path, as long as it is reversible, the same work of adhesion values are obtained, but the numerical efficiency differs greatly.
JOURNAL OF PHYSICAL CHEMISTRY A
(2022)
Article
Nanoscience & Nanotechnology
Takamasa Saito, Ryo Takebayashi, Masaki Kubo, Takao Tsukada, Eita Shoji, Gota Kikugawa, Donatas Surblys
Summary: In this study, the affinity between surface-modified nanoparticles and solvents was investigated using molecular dynamics simulations. The results showed that the effect of modifier length on affinity was small at a surface coverage of 100%, while at a surface coverage of 50%, both modifier length and solvent length had a significant impact on affinity. Furthermore, it was demonstrated that adjusting the surface coverage and surface modifier could increase the affinity between modified nanoparticles and solvents.
Article
Thermodynamics
Yinbo Zhao, Gota Kikugawa, Yoshiaki Kawagoe, Keiichi Shirasu, Tomonaga Okabe
Summary: In this study, nonequilibrium molecular dynamics simulations were used to investigate the relationship between thermal conductivity and epoxy resin structure. The results confirmed that introducing crosslinking bonds predominantly contributes to higher thermal conductivity in epoxy materials.
INTERNATIONAL JOURNAL OF HEAT AND MASS TRANSFER
(2022)
Article
Thermodynamics
Haiyi Sun, Donatas Surblys, Hiroki Matsubara, Taku Ohara
Summary: The understanding of interfacial heat transfer mechanism is increasingly important in thermal management due to the role of interfacial thermal resistance as electronic devices reduce in size. This study used molecular dynamics to investigate interfacial heat transfer between diverse silica surfaces and two organic liquids: triacontane and triacontanol. Silica surfaces with silanols showed better thermal transport ability with triacontane/triacontanol due to a vibration matching effect. The increase of silanol area number density enhanced interfacial heat transfer for silica-triacontanol systems, but had little effect on silica-triacontane systems. Moreover, temperature significantly affected the interfacial heat transfer of silica-triacontanol systems, reducing the number and lifetime of hydrogen bonds.
INTERNATIONAL JOURNAL OF HEAT AND MASS TRANSFER
(2023)
Article
Chemistry, Physical
Takamasa Saito, Masaki Kubo, Takao Tsukada, Eita Shoji, Gota Kikugawa, Donatas Surblys, Momoji Kubo
Summary: Controlling the dispersion state of nanoparticles in a polymer matrix is crucial for the production of polymer nanocomposites. This study used molecular dynamics simulations to investigate the influence of surface coverage, modifier length, and polymer species on the interfacial structure and affinity between surface-modified Al2O3 nanoparticles and polymer melts. The results showed that the interfacial affinity could be improved by adjusting the surface coverage and modifier species.
JOURNAL OF CHEMICAL PHYSICS
(2023)
Article
Physics, Fluids & Plasmas
Hiroki Matsubara, Donatas Surblys, Taku Ohara
Summary: A recent study revealed that interfacial thermal resistance at solid-liquid interfaces can be minimized by adjusting the molecular mass of the surfactant. This study utilized a one-dimensional harmonic chain model and the nonequilibrium Green's function method to explain the mechanism of thermal resistance minimization, and established the relationship between thermal resistance and vibrational density of states overlap.