Pressure Profile And Its Application For A Hydrogen Bonding Fluids Confined In A Spherical Cavity

The classical density functional theory is used to investigate the pressure tensor,fluid-wall encapsulation energy and surface tension for a hydrogen bonding(HB)fluid confined in a spherical nanocavity.Firstly,an angle-depended square well potential is pre-averaged to give the effective two-body hydrogen bonding interaction potential by the principle of statistical mechanics.Then,the classical density functional theory is employed to obtain the equilibrium density profile in both open and closed nanocavity,by which the pressure tensor of the confined fluid is calculated.Furthermore,the fluid-wall encapsulation energy and surface tension under different conditions are presented by means of the corresponding pressure tensors.These quantities show a significant dependence on the hydrogen bonding strength,functionality,bulk density(average density)and dimension of the nanocavity.Finally,some distinct differences between these quantities of the fluids under two types of confinements are found.This thesis aims to provide some helpful clues for further revealing the aggregated structure and related physicochemical properties of confined HB fluids.The main contents of the thesis are given as follows:Chapter I: Summary.Some related physical quantities of confined fluids and the development of the density functional theory are outlined.Also,the main components of the present thesis are introduced.Chapter II: Pressure tensor of a HB fluid confined in an open system.First of all,the main theoretical model of the present thesis is introduced.The angle-averaged method is used to obtain the interparticle interaction that depends only on the distance between two particles.The classical density functional theory is then employed to obtain the equilibrium density profile of HB fluid within an open nanocavity,by which the pressure tensor,fluid-wall encapsulation energy and surface tension of the HB fluid are presented.As an application,the pressure tensor,fluid-wall encapsulation energy and surface tension are illustrated under different conditions.Chapter III: Pressure tensor of a HB fluid confined in a closed system.The pressure tensor,fluid-wall encapsulation energy and surface tension of a HB fluid confined in a closed spherical cavity are calculated.Correspondingly,the pressure tensor,fluid-wall encapsulation energy and surface tension are illustrated under different conditions.Finally,some distinct differences between these quantities of the fluids under two types of confinements are performed.Chapter IV: Conclusions and prospects.We summarized the main research results of the present thesis,and then some drawbacks in our treatments and several possible modifications are pointed out.