Theoretical Study On Interfacial Water Induced Surface Structure Of Molecular Sieves And Biomimetic Membrane

Water is the common but important substance in nature.About 71%of the earth's surface is covered with water.Water is the source of life,almost all the life cannot live without water.The interaction between water and the outside world is mainly achieved by surface water contact,interfacial water plays important roles on surface wetting,electrochemical reaction,catalysis,etc.In biology,water molecules don't just provide a solvent environment,but actively participate in various biological processes,such as promoting protein folding,regulating molecular recognition,and so on.With the development of nanotechnology and theoretical research,people can study the properties of interfacial water from the molecular scale.Usually,interfacial water refers to the water of several nanometers on the interface.The interfacial water interact with both the interface and the water around them,and thus had different properties from bulk water.The interactions between interfacial water and interface are mutual.Not only does surface affect the structure and dynamic properies of water molecules but also water molecules may participate in the interface formation that affects the structure and properties of the interface.In this paper,we researched the interfacial water in inorganic materials and biomimetic membranes from a microscopic scale using molecular dynamics simulation methods.1?Using molecular dynamics simulations,we studied the application of interfacial water in inorganic materials.The main contents of the study were interfacial water-induced orientated growth of zeolite crystals.The interfacial water connected to graphene oxide and zeolite surface by hydrogen bonds,the graphene oxide had different degree of adsorption on the three crystal faces of zeolite{100},{010}and{101},the adsorption-stable surface growth is inhibited,and the weakly adsorbed surface can continue to grow,thereby inducing the orientated growth of the crystal.Experimental collaborators verified our theoretical results by adding graphene oxide to the synthesis of zeolite and prepared well-dispersed,faceted Si-ZSM-5 crystals and oriented growth of the Si-ZSM-5 crystals along the c-axis.This work has research significance for the controllable growth of crystallographic morphology of inorganic materials,and has potential application in the fields of optics,catalysis and energy.2?Inspired by antifreeze proteins,combining molecular dynamics simulations and experiments,we found that the interfacial water plays important role in the inhibition of ice crystal growth and recrystallization by graphene oxide.The ordered ice like structure and slowly dynamics properties of interfacial water make graphene oxide tend to form much more number and longer lifetime hydrogen bonds with the ice-like water than liquid water,the adsorption of GO to the ice crystal interface in liquid water leads to curved ice crystal surface.Therefore,the growth of ice crystal is suppressed owing to the Gibbs–Thompson effect.In experiments,we observed that graphene oxide(GO)greatly suppresses the growth and recrystallization of ice crystals,ice crystals display a hexagonal shape in the GO dispersion and we first utilize GO for the cryopreservation of cells.This work opens a new variety of avenues for the application of 2D materials and promotes the better understanding of ice crystal formation at the molecular level.3?Combing molecular dynamics simulations with theoretical spectroscopic calculations and experimental comparisons,we researched the interfacial water structure and ion distribution at charged biomimetic membrane(SAM-COO~-)aqueous interface.We found that 88%of the first layer of interfacial water formed two hydrogen bonds with two-COO~-groups at the interface,embedded in the interface and participate the formation of the interface to makde the interface stable.Interestingly,Na~+has the sharing structure with three neighbor-COO~-groups of SAM-COO~-at interface,similar to that in crystals and different to that in solution.The theoretical simulation shows the ion distribution and water structure at the charged surface on the molecular level,and experimental and theoretical spectra verified our theoretical simulation results.Our results provide new insights for a better understanding of electrochemically and biologically related charged interfaces at molecular level and should be helpful to design the nanodevices and bioinspired human-made nanomaterials.