International Journal of Thermal Sciences 47 (2008) 1602–1609 www.elsevier.com/locate/ijts Atomistic-mesoscale interfacial resistance based thermal analysis of carbon nanotube systems V.U. Unnikrishnan a , D. Banerjee b , J.N. Reddy a,∗ a Advanced Computational Mechanics Laboratory, Department of Mechanical Engineering, Texas A&M University, College Station, TX 77843-3123, USA b Multi Phase Flows and Heat Transfer Laboratory, Department of Mechanical Engineering, Texas A&M University, College Station, TX 77843-3123, USA Received 15 May 2007; received in revised form 15 October 2007; accepted 22 October 2007 Available online 10 April 2008 Abstract This paper estimates the effect of chemical additives like CuO on the interfacial thermal resistance of carbon nanotubes (CNTs) embedded in water. The investigation of thermal properties of CNT nanostructure is carried out using molecular dynamics (MD) simulations. The nanotube was heated to a prescribed temperature, followed by the relaxation of the entire configuration. In the equilibration simulations, the atoms in the nanotube are heated instantaneously to 500, 750 and 1000 K in 3 separate simulations by rescaling the velocities of carbon atoms in the nanotube. This paper also deals with the mesoscale thermo-conductivity properties of the composite system, by employing various effective medium theories and micromechanical methods.  2007 Elsevier Masson SAS. All rights reserved. Keywords: Carbon nanotube; Molecular dynamics; Universal force field potential; Interfacial thermal resistance; Effective medium theories; Thermal conductivity 1. Introduction Carbon nanotubes (CNTs) are present mainly in three con- figurations: single-walled carbon nanotubes (SWNT), multi- walled carbon nanotubes (MWNT), and carbon nanotube bun- dles or ropes. These configurations are many orders of magni- tude stronger, stiffer, conductive, and lighter than the best avail- able carbon fibers [1–8]. The perfect formation of nano-unit cells and the ease by which the structural as well as functional units can be manipulated helps in finding exciting structural applications [2]. For the manipulation of nanoscale systems, molecular level study involving interactions at the atomic scale need to be analyzed. The simulation of molecular systems is based on the assumption that the atomic interactions are de- scribed by means of classical mechanics models [6,7,9–11]. Studies in the mechanical, electrical and thermal behavior of CNTs were focused primarily on the use of empirical potentials using molecular dynamics (MD) and continuum models using the elasticity theory [6–8,12,13]. Even though MD simulations * Corresponding author. Tel.: +1 979 862 2417; fax: +1 979 845 3081. E-mail address: jnreddy@tamu.edu (J.N. Reddy). are popular in the atomistic scale, the computational adapta- tions to model macroscopic problems based on CNTs are not completely established. Research in the determination of overall properties of the composite systems are carried out with a bottom to top ap- proach [6,14]. Of late, greater focus is on the accuracy in pre- dicting the lower order properties and hierarchical transfer of the material properties to a larger scale. In the previous works on multiscale modeling, the response in the atomistic level was transferred to the mesoscale or microscale by the explicit use of “equivalence of the response variables” [14]. In the atomistic level the interactions are modeled using pair potentials to re- spond to externally applied disturbance. The response variables in the lower scales are passed on to the next higher scale, seek- ing change in the material properties. This method is justified, since the material response at an atomistic scale is highly non- linear [11] and any change in the local environment has been found to vary the properties of the atomistic system dramati- cally [6]. Numerous theoretical models predict that an addition of even a low volume fraction of CNTs would result in an increase in thermal conductivity of a composite system [15–17]. Inter- 1290-0729/$ – see front matter  2007 Elsevier Masson SAS. All rights reserved. doi:10.1016/j.ijthermalsci.2007.10.012