Phase Behaviors Of Fluids In A Slit Pore With Broken Symmetry

Phase behaviors and aggregated structures property of hydrogen bonding(HB) fluids and Lennard-Jones fluids confined in a slit pore with broken symmetry were investigated by using the density functional theory(DFT) incorporated with the fundamental measure theory(FMT) and the modified fundamental measure theory(MFMT). Fristly, the grand potential functional is constructed by the DFT. Then, the equilibrium density profiles of various conditions are obtained by minimizing the grand potential functional. In terms of adsorption-desorption isotherms and the corresponding grand potentials, phase diagrams and interfacial properties of fluids under various conditions were presented. Furthermore, through phase coexistences of laying transition and capillary condensation, the effects of the broken symmetry, pore width, fluid molecular interactions and fluid-pore interaction on the phase equilibrium properties and interfacial properties were addressed. It is expected that the present results are helpful to study the phase equilibria and interfacial properties of fluids under various broken symmetry restrictions.The dissertation is mainly composed of the following four chapters:Chapter 1: Summary. This chapter mainly gives an introduction to the research background, research methods, research contents and its significance. Furthermore, a brief history of the development of density functional theory and its research status were also reviewed.Chapter 2: Introduction of density functional theory. The grand potential functional was constructed by using DFT incorporated with FMT and MFMT. Then, the functional of the intrinsic Helmholtz free energy, the chemical potential in the bulk phase and the external potential can also be expressed. Finally, by minimizing the grand potential functional, the equilibrium density profile was obtained.Chapter 3: Phase behaviors of fluids confined in a slit pore with broken symmetry. Based on the adsorption-desorption isotherms and the corresponding grand potentials, phase diagrams of fluids under various conditions are presented. In this chapter, two different fluids, which are hydrogen bonding fluids and Lennard-Jones fluids, were mainly investigated. In addition, the effects of the broken symmetry, pore width, fluid molecular interactions and fluid-pore interaction on the phase equilibrium properties were also addressed.Chapter 4: Interfacial properties of hydrogen bonding fluids confined in a slit pore with broken symmetry. Fristly, the interfacial properties of hydrogen bonding fluids confined in the asymmetrical slit pores were investigated. What's more, with the help of adsorption-desorption isotherms and grand potentials, the interfacial properties of hydrogen bonding fluids under various conditions were obtained, and the effects of related factors on the interfacial properties were also presented.