The behavior of the thermal conductivity near the melting temperature of copper nanoparticle

doi:10.1016/j.molliq.2015.07.074

Journal of Molecular Liquids

Volume 211, November 2015, Pages 695-704

https://doi.org/10.1016/j.molliq.2015.07.074 Get rights and content

Highlights

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Interaction between copper atoms was modeled by Embedded Atom Method (EAM).
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Melting points for Cu nanoparticles and its bulk simulated using the EAM potential.
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The melting point of particle size agrees with that from the analytical model.
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Molecular dynamics simulations through Green–Kubo method are used.
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Prediction and study of the thermal conductivity for Cu nanoparticles and its bulk

Abstract

In this work, molecular dynamics simulations have been applied to calculate the thermal conductivity and the melting temperature of copper nanoparticle and its bulk, through Green–Kubo framework. Then the melting temperature was predicted by analyzing the temperature dependence of the total energy and the heat capacities, for different particles size range 47 ≤ N ≤ 2319 and for various temperatures range 90 ≤ T ≤ 1500 K, using Embedded Atom Method to simulate the interactions between Copper atoms. The global behavior shows that the melting temperature of Cu nanoparticles increases when their sizes increase. Moreover, the trend observed in the melting point with respect to particle size agrees with the analytical models. Likewise the melting temperature of bulk is in a good agreement with the experimental and simulations values. In overall terms, the thermal conductivity had a peak near the melting temperature, and increase with the increasing size of nanoparticle.

Graphical abstract

Introduction

Owing to its fundamental and pragmatic significance, during the last decades, considerable research efforts have been devoted to the study of nanoparticles, which are particles with size in the range of 1 to 100 nm, at least in one of the three possible dimensions. In this size range, the physical, chemical and biological properties of the nanoparticle change in fundamental ways from the properties of both individual atoms/molecules and its corresponding bulk material. Nanoparticles can be produced from materials of several chemical nature, starting from the most common metals (Cu, Ag, Au), until the most complicated one (Carbon nanotube, Multi-wall Carbon nanotube) [1], [2]. Obviously, Copper nanoparticles manufactured in ambient atmospheric temperature and pressure inevitably have surface oxide layers because the Cu oxide phases are thermodynamically more stable than pure Cu. Furthermore, copper nanoparticles are found to aggregate severely without proper protection. The problems of aggregation and oxidation can be circumvented by sonication or the use of various protecting agents, such as polymers and organic ligands [3], [4], [5], [6], [7]. Presently, synthesis methods were developed for copper nanoparticles using chemical reduction [4], [5], [6], [7], thermal decomposition [8], polyol [9], laser ablation [10], electron beam irradiation [11], [12]. Interest in copper nanoparticles arises from the useful properties of this metal such as the good thermal and electrical conductivity at a low cost. These features lead to potential application in many industrial sectors, particularly nanofluids which are used in cooling fluids for electronic systems, heating, cooling exchanger including transportation and energy production. Therefore, nanofluids containing suspended nanoparticle of copper showed large enhancement of thermal conductivity relative to those of pure fluids such as (Cu–Ar) nanofluid [13], [14]. Extensive literature has been conducted in the past decade to investigate and predict various proprieties, heat transfer performance and the effective thermal conductivity of nanofluid consisting of several nanoparticles [15], [16], [17], [18], [19], [20], [21]. Some studies have used the lattice Boltzmann method (LBM) for investigating different characteristics of nanofluide these studies are listed [22], [23], [24], [25], [26], [27]. The lattice Boltzmann method (LBM) is a powerful numerical technique, based on kinetic theory, for simulating fluid flows and modeling the physics of fluids.

In the numerical side a very wide number of techniques have been established to calculate the thermal conductivity of nanoparticles and one of the most important is molecular dynamics simulations using Green–Kubo framework; such as the determination of carbon nanotubes and graphene sheets thermal conductivity, and their dependence on temperature [28], [29], [30].

The melting temperature is an enigmatic point that is still under intensive investigation, and it's one of the most important phase transitions in materials science and engineering, hence predicting melting temperature for bulk material is a very hard task and obviously nontrivial for the case of nanoparticles [31]. Therefore, the standard computational method is dependent on analyzing the different properties of the solid phase (such as total energy, heat capacity and radial distribution function…etc.). Voluminous body of numerical investigations was using classical molecular dynamics to calculate the exact melting temperature of materials in bulk form [31], [32], [33]. In this work, the MD simulation is used to calculate the melting temperature of copper bulk and copper nanoparticles, also its dependence on the size of nanoparticles. Then, through Green–Kubo method the thermal conductivity of copper nanoparticle and its bulk are examined as a function of temperature.

Section snippets

Inter-atomic potentials

A number of computational disciplines were using embedded-atom method such as chemistry and computational physics. Rigorously speaking EAM is an approximation describing the energy between atoms as an interatomic potential widely used in molecular dynamics simulations, where the energy is a function of a sum of functions of the separation between an atom and its neighbors. In the present (EAM) version of Daw, Baskes, and Foiles is used to compute pairwise interactions of copper atoms [34], [35]

MD simulation

The main idea of this work is to study the behavior of the thermal conductivity near the melting temperature by comparing the influence of nanoparticle size on its melting temperature with its corresponding bulk. Hence, this work aims to fill this void in the existing literature. To perform this simulation, first the molecular dynamics (MD) simulations for Cu bulk are executed out in a NVT, with a periodic boundary conditions, Cu atoms placed in a face centered cubic lattice Fig. 1 and

Melting temperature from total energy and heat capacity

Melting temperature was usually predicted by studying the variation in thermodynamic properties such as total energy, specific heat capacity, or some other physical properties. However, before embarking upon the presentation and discussion of the new results, it is desirable to indicate that the total energy and the heat capacity present a strong indication of the melting temperature, so it is required to establish that the transition from solid to liquid occurs when the total energy of

Conclusion

Molecular dynamics simulations (MD) are applied to study melting temperature of Copper nanoparticle via Green–Kubo (GK) method to predict the thermal conductivity of Copper nanoparticle, for various sizes, range 47 ≤ N ≤ 2319 and for different system temperatures, range 90 K ≤ T ≤ 1500 K. Potentials based on the Embedded Atom Method (EAM) have been used to calculate total energy and heat capacity, and then the melting temperature was estimated from the total energy and heat capacity. The result from

References (57)

X. Zhang et al.
A. Wang
Mater. Res. Bull.
(2006)
X. Cheng et al.
Appl. Surf. Sci.
(2006)
M. Salavati-Niasari et al.
Polyhedron
(2009)
B.K. Park et al.
J. Colloid Interface Sci.
(2007)
F. Zhou et al.
Radiat. Phys. Chem.
(2008)
K. Mallick et al.
Eur. Polym. J.
(2006)
Y.S. Lin et al.
Int. J. Therm. Sci.
(2012)
H. Zerradi et al.
Adv. Powder Technol.
(2014)
D.W. Zhou
Int. J. Heat Mass Transfer
(2004)
A.K. Santra et al.
Int. J. Therm. Sci.
(2009)

M. Sheikholeslami et al.

Physica A

(2015)

M. Sheikholeslami et al.

Int. J. Heat Mass Transfer

(2015)

M. Sheikholeslami et al.

Physica A

(2015)

H.R. Ashorynejad et al.

Int. J. Therm. Sci.

(2013)

M.H. Khadem et al.

Chem. Phys. Lett.

(2013)

Q.S. Mei et al.

Progress

Mater. Sci.

(2007)

V.G. Grigoryan et al.

Chem. Phys. lett.

(2003)

G.A. Fernandez et al.

Fluid Phase Equilib.

(2004)

S. Plimpton

J. Comput. Phys.

(1995)

M. Abbaspour et al.

Fluid Phase Equilib.

(2014)

H. Akbarzadeh et al.

Fluid Phase Equilib.

(2009)

S. Horikoshi et al.

Microwaves in Nanoparticle Synthesis: Fundamentals and Applications

(2013)

R. Nagarajan et al.

Nanoparticles: Synthesis, Stabilization, Passivation, And Functionalization

(2008)

S. Giuffrida et al.

J. Nanopart. Res.

(2008)

C. Wu et al.

J. Nanoparticle Res.

(2006)

H.X. Zhang et al.

Nanoscale Res. Lett.

(2009)

V. Amendola et al.

Phys. Chem. Chem. Phys.

(2009)

W. Cui et al.

RSC Adv.

(2014)

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View full text

The behavior of the thermal conductivity near the melting temperature of copper nanoparticle

Highlights

Abstract

Graphical abstract

Introduction

Section snippets

Inter-atomic potentials

MD simulation

Melting temperature from total energy and heat capacity

Conclusion

Mater. Res. Bull.

Appl. Surf. Sci.

Polyhedron

J. Colloid Interface Sci.

Radiat. Phys. Chem.

Eur. Polym. J.

Int. J. Therm. Sci.

Adv. Powder Technol.

Int. J. Heat Mass Transfer

Int. J. Therm. Sci.

Physica A

Int. J. Heat Mass Transfer

Physica A

Int. J. Therm. Sci.

Chem. Phys. Lett.

Mater. Sci.

Chem. Phys. lett.

Fluid Phase Equilib.

J. Comput. Phys.

Fluid Phase Equilib.

Fluid Phase Equilib.

Microwaves in Nanoparticle Synthesis: Fundamentals and Applications

Nanoparticles: Synthesis, Stabilization, Passivation, And Functionalization

J. Nanopart. Res.

J. Nanoparticle Res.

Nanoscale Res. Lett.

Phys. Chem. Chem. Phys.

RSC Adv.