Molecular Dynamics Simulation Research On Water Slip And Gel Adhesion Of Interfacial System

With the decrease of the spatial scale,the interface effect produced by the dramatic increase of the specific surface area makes the influence of the surface and interface on the macroscopic properties of the system can not be ignored,and there are often physical and chemical phenomena near the interface that are different from those in the bulk phase.To clarify the surface and interface mechanism helps to understand this physical and chemical phenomenon different from bulk.In this paper,molecular simulation studies are carried out on two phenomena at the micro-nano interface:slip phenomenon and adhesion phenomenon.The results of the study are as follows:(1)Slip phenomenon refers to the phenomenon that the fluid near the interface flows through the interface in a sliding state.The existence of slip phenomenon reduces the surface resistance,which is of great significance for studying the process of mass transfer enhancement in nanopores.In this paper,molecular dynamics methods are mainly used,and the shear rate,wettability,pore morphology and roughness at the surface of the nano-slit are used as the investigating factors to study the sliding phenomenon of water in the nano-slit.The slip length obtained by molecular dynamics in this paper is in good agreement with the slip length of water on diamond-like carbon and silicon measured by atomic force microscope in the experiment.It is found that the shear speed has a small effect on the slip length.And as the hydrophilicity gradually increases,the slip length gradually decreases until no slip occurs.For nanochannels with rectangular surfaces and triangular rough surfaces,the greater the roughness,the smaller the slip length until no slip occurs.(2)Due to the huge specific surface area of the nanoparticles,the interface effect produced can greatly change the macroscopic properties of the system,such as the adhesion process of the gel.By introducing nanoparticles,the adhesive strength of the gel is significantly enhanced.In this paper,molecular dynamics methods are used to study the process of nanoparticle adhesion to gel.The attraction of nanoparticles to the gel and the size of the nanoparticle are used as investigative factors to study the behavior of gel adhesion.The result is that the size of nanoparticles and the surface chemistry of the gel can be adjusted and controlled to achieve better gel adhesion.The study of phenomena at these interfaces shows that changing the interaction between the surface of the material and the surface substance can effectively control the physical and chemical properties and dynamic behavior of the system,so as to achieve the purpose of optimizing process efficiency.