Thermal Boundary Characteristics of Homo-/Heterogeneous Interfaces

Abstract

The interface of two solids in contact introduces a thermal boundary resistance (TBR), which is challenging to measure from experiments. Besides, if the interface is reactive, it can form an intermediate recrystallized or amorphous region, and extra influencing phenomena are introduced. Reactive force field Molecular Dynamics (ReaxFF MD) is used to study these interfacial phenomena at the (non-)reactive interface. The non-reactive interfaces are compared using a phenomenological theory (PT), predicting the temperature discontinuity at the interface. By connecting ReaxFF MD and PT we confirm a continuous temperature profile for the homogeneous non-reactive interface and a temperature jump in case of the heterogeneous non-reactive interface. ReaxFF MD is further used to understand the effect of chemical activity of two solids in contact. The selected Si/SiO 2 materials showed that the TBR of the reacted interface is two times larger than the non-reactive, going from 1 . 65 × 10 - 9 to 3 . 38 × 10 - 9 m 2 K/W. This is linked to the formation of an intermediate amorphous layer induced by heating, which remains stable when the system is cooled again. This provides the possibility to design multi-layered structures with a desired TBR.

Mass diffusivity and thermal conductivity estimation of chloride-based salt hydrates for thermo-chemical heat storage: A molecular dynamics study using the reactive force field.

“…In our previous studies [26,35] on Pt and Ni systems, we observed that the thermal conductivity scales with the length of the simulated molecular system. SS-NEMD simulations of different system sizes of Pt and Ni are required to extrapolate to the infinite size thermal conductivities, which is equal to the theoretical thermal conductivity of a bulk material.…”

“…Steady-state Non-Equilibrium Molecular Dynamics (SS-NEMD) simulations using the reactive force field are performed to calculate the thermal conductivity of MgCl 2 • nH 2 O (n = 0, 1, 2, 4 and 6), and CaCl 2 • 2H 2 O. This is an often used MD method to compute the thermal conductivity [25][26][27][28] . The size of the cross-sectional area and length of the system along the heat flow direction affect the thermal conductivity at a molecular level [27,28] .…”

Gibbs Ensemble Monte Carlo for Reactive Force Fields to Determine the Vapor–Liquid Equilibrium of CO2 and H2O

“…16,17 Numerous classical force fields have been developed, e.g., TIP4P/2005 18 for H 2 O and TraPPE 19 for CO 2 . By using such a force field, important properties such as the adsorption and diffusion of fluids in porous media 11,12,20 and thermal behavior 11,21 of materials can be predicted.…”

“…Furthermore, an important requirement for molecular studies of fluids in porous media is the correct description of the vapor–liquid equilibrium (VLE) by the force field. , Numerous classical force fields have been developed, e.g., TIP4P/2005 for H 2 O and TraPPE for CO 2 . By using such a force field, important properties such as the adsorption and diffusion of fluids in porous media ,, and thermal behavior , of materials can be predicted.…”

Modeling of Complex Interfaces: From Surface Chemistry to Nano Chemistry

“…In addition to this, there is a paper describing a study of the thermal boundary characteristics of homo-and heterogeneous, reactive, and nonreactive interfaces between two solids by Heijmans et al [3]. Via a connection between reactive force field molecular dynamics and phenomenological theory, a continuous temperature profile was found for the homogeneous nonreactive interface, while a temperature jump was found for the heterogeneous nonreactive interface.…”