Pham Van-Trung, Fang Te-Hua
Department of Mechanical Engineering, National Kaohsiung University of Science and Technology, Kaohsiung, 807, Taiwan.
Department of Mechanical Engineering, Pham Van Dong University, Quang Ngai, 570000, Vietnam.
Sci Rep. 2022 May 11;12(1):7777. doi: 10.1038/s41598-022-11883-5.
For practical application, determining the thermal and mechanical characterization of nanoporous two-dimensional MoS membranes is critical. To understand the influences of the temperature and porosity on the mechanical properties of single-layer MoS membrane, uniaxial and biaxial tensions were conducted using molecular dynamics simulations. It was found that Young's modulus, ultimate strength, and fracture strain reduce with the temperature increases. At the same time, porosity effects were found to cause a decrease in the ultimate strength, fracture strain, and Young's modulus of MoS membranes. Because the pore exists, the most considerable stresses will be concentrated around the pore site throughout uniaxial and biaxial tensile tests, increasing the possibility of fracture compared to tensing the pristine membrane. Moreover, this article investigates the impacts of temperature, porosity, and length size on the thermal conductivity of MoS membrane using the non-equilibrium molecular dynamics (NEMD) method. The results show that the thermal conductivity of the MoS membrane is strongly dependent on the temperature, porosity, and length size. Specifically, the thermal conductivity decreases as the temperature increases, and the thermal conductivity reduces as the porosity density increases. Interestingly, the thermal and mechanical properties of the pristine MoS membrane are similar in armchair and zigzag directions.
对于实际应用而言,确定纳米多孔二维二硫化钼(MoS)膜的热学和力学特性至关重要。为了了解温度和孔隙率对单层MoS膜力学性能的影响,使用分子动力学模拟进行了单轴和双轴拉伸试验。研究发现,随着温度升高,杨氏模量、极限强度和断裂应变均降低。同时,孔隙率效应导致MoS膜的极限强度、断裂应变和杨氏模量下降。由于存在孔隙,在整个单轴和双轴拉伸试验过程中,最大应力将集中在孔隙部位周围,与拉伸原始膜相比,增加了断裂的可能性。此外,本文使用非平衡分子动力学(NEMD)方法研究了温度、孔隙率和长度尺寸对MoS膜热导率的影响。结果表明,MoS膜的热导率强烈依赖于温度、孔隙率和长度尺寸。具体而言,热导率随温度升高而降低,且随孔隙率密度增加而减小。有趣的是,原始MoS膜在扶手椅方向和锯齿方向的热学和力学性能相似。