Molecular Dynamics Study On Wetting Properties Of Monolayer MoS₂

Molybdenum disulfide?MoS₂?as a typical representative of transition metal dichalcogenides?TMDC?,it has excellent physical and chemical properties and broad application prospects in flexible electronic devices,low-power electronic devices,and optical devices,etc.The wetting behavior of the material at micro-nanometer scale has a significant effect on the device performance,in this thesis,we use the molecular dynamics method to simulate the wetting process of water droplets on monolayer molybdenum disulfide,and discuss the effect of temperature,strain,charge density and material configuration on its wetting properties.The main contributions of this thesis are as follows:?1?A brief introduction of the excellent physical and chemical properties of molybdenum disulfide materials and their wide application prospects are given.The structural characteristics of monolayered molybdenum disulfide are described in detail.It is pointed out that different phases of molybdenum disulfide can be obtained by different preparation methods,and summarizes the research status of molybdenum disulfide wetting characteristics at home and abroad.?2?Starting from the wetting phenomena in nature,we introduced four classical wetting theoretical models and characterization methods of wetting characteristics,and briefly introduced the basic ideas,basic algorithms and details of the simulation process of molecular dynamics methods.In this thesis,the potential functions selected by the molecular dynamics method to simulate the wetting behavior of molybdenum disulfide are introduced in detail,including the LJ potential function,the REBO potential function of molybdenum disulfide,and the correction process of LJ potential function parameters between water molecules and molybdenum disulfide.?3?Four single layer molybdenum disulfide wetting models were established based on the molybdenum disulfide configuration?1T phase,2H phase?and chirality?armchair type,zigzag type?,and related potential functions were selected and parameters settings.The wettability characteristics of 1T phase and 2H phase MoS₂ at room temperature were simulated and analyzed.It was found that the contact angles of water droplets on the 1T phase and 2H phase MoS₂ were 70°-75°and 65°-70°,respectively,which were all moderately hydrophilic materials,and the wetting behavior is approximately isotropic.?4?The effects of temperature,uniaxial tensile strain and charge density on the wettability of monolayer MoS₂ were studied.It was found that increasing the temperature and increasing the tensile strain can increase the contact angle of water droplets on the 1T phase and 2H phase MoS₂,carrying charges will make MoS₂ superhydrophilic.Through the molecular dynamics simulations of the wetting properties of monolayer molybdenum disulfide,the effects of temperature,strain,charge density and material configuration on the wetting behavior of water droplets on the surface of molybdenum disulfide were explored,it provides a theoretical reference for future application of molybdenum disulfide in flexible electronic devices,low-power electronic devices,and surface modification.