Molecular Dynamics Simulation of the Crystallization Behavior of Octadecane on a Homogeneous Nucleus

Abstract

Latent heat storages have the ability to contribute to a more sustainable energy supply network. However, phase change materials (PCM) used for latent heat storages often show supercooling. This phenomenon takes place whenever the PCM begins crystallizing below the freezing point and is one of the biggest drawbacks holding back the widespread use of PCM. Nucleation agents (NA) can be used to avoid the supercooling, yet the choice of an effective NA is not straightforward. In this work, molecular dynamics (MD) simulation was tested in order to simulate the crystallization of Octadecane on a NA. The simulation results include density, phase change temperature and enthalpy as well as the crystal structure and lie in good agreement with literature values and the authors’ own experimental data. Further simulations of the crystallization process on different surfaces of homogeneous nuclei acting as a NA were performed. The results reflect the hypothesis that liquid molecules start crystallizing easier on surfaces exposing the whole chain side rather than the chain ends. With the result, that the choice of parameters for the MD simulation represent the Octadecane system reliably and further studies can be performed including heterogeneous NA.

Influence of Functionalization on the Crystallinity and Basic Thermodynamic Properties of Polyethylene

“…Solution processing from a dilute polymer solution can result in a higher degree of polymer crystallinity than materials “cast” in thin film. , A full understanding of nucleation and growth mechanisms − for polymer crystallization at a molecular level, and even the propensity for chain folding to form lamellae, remains a substantial challenge. Given this situation, computer simulation methods can be a powerful tool to provide insights into thermal structural ordering − under amorphous bulk conditions for alkanes and PE, and single chain crystallization. − The downside of the computer simulations is that only limited material size and time scales can be considered.…”

Nanofibrous membranes with hydrophobic and thermoregulatory functions fabricated by coaxial electrospinning

“…18,19 Oct is a commonly used organic PCM, which has attracted wide attention due to its high heat storage, great thermal stability, non-toxicity, and phase transition temperature close to human body temperature. 20,21 To overcome the leakage problem of PCMs, fabric finishing, 22 microcapsule treatment 23,24 and coaxial electrospinning 25,26 are generally used to encapsulate them. The initial two methods are complex and inconvenient to use, with certain limitations.…”

“…As a thermal management material, PCMs can absorb or release heat to maintain a constant temperature by changing the phase of matter, and have excellent performance in energy storage and conversion 18,19 . Oct is a commonly used organic PCM, which has attracted wide attention due to its high heat storage, great thermal stability, non‐toxicity, and phase transition temperature close to human body temperature 20,21 . To overcome the leakage problem of PCMs, fabric finishing, 22 microcapsule treatment 23,24 and coaxial electrospinning 25,26 are generally used to encapsulate them.…”