【作者】 赵萌；

【导师】 顾芳； 王海军；

【作者基本信息】 河北大学 ， 高分子化学与物理， 2017， 硕士

【摘要】 氢键流体在自然界中普遍存在,并在生物、化工、物理、医药和超分子领域有着重要应用。氢键流体具有一般流体的近程有序和远程无序的特征,同时也是较为复杂的非均相流体,其在介观尺度下具有特殊结构和性质。众所周知,渗透压问题在生物生理过程中起着至关重要的作用。有鉴于此,深入理解介观尺度下复杂流体的聚集态结构与渗透压具有重要意义。本文基于经典流体的密度泛函理论(DFT)以及改进的基本度量理论(MFMT),研究了介观尺度下半透膜附近胶体—氢键流体的聚集态结构和渗透压。在研究中,选取理想化半透膜模型作为研究体系,半透膜仅允许作为溶剂的氢键流体通过而不允许作为溶质的胶体粒子通过。在具体计算时,首先构建以流体分子数密度为变量的体系巨势泛函,并利用巨势最小原理得到体系平衡密度分布,根据所获得的平衡密度分布进一步研究了体系渗透压。深入讨论了两组分体相密度、分子尺寸比例、氢键作用等因素对流体聚集态结构和渗透压的影响。研究结果旨在为进一步揭示受限流体聚集态结构和生物生理过程中渗透现象提供可能的理论线索。本文共四个部分,主要内容如下:第1章:绪论。本章主要介绍了论文的研究背景和意义,具体包括氢键流体、渗透压的性质及其重要意义,同时简要回顾了经典流体密度泛函理论的发展历程并给出了硬球部分自由能泛函的理论表达式。第2章:单壁半透膜附近胶体—氢键流体的聚集态结构及渗透压研究。本章详细研究了单壁半透膜附近胶体—氢键流体的聚集态结构。首先给出了研究模型及体系氢键部分的自由能泛函理论表达式,并依据密度泛函理论得到不同条件下单壁半透膜附近胶体—氢键混合流体的平衡密度分布,进而根据计算结果分析了体系聚集态结构。作为应用进一步计算了体系的渗透压。深入讨论了氢键作用(氢键作用强度及氢键官能度)、体相密度、分子尺寸比例等因素对流体聚集态结构及体系渗透压的影响。第3章:球形半透膜附近胶体—氢键流体聚集态结构。本章主要研究了球形半透膜附近的胶体—氢键流体的平衡密度分布,并探讨了各组分体相密度、分子尺寸、氢键强度、官能度以及球腔尺寸等因素对受限流体聚集态结构的具体影响。第4章:总结与展望。对本文所做工作进行了总结,并对后续工作及相关领域的发展前景作了简要说明。更多还原

【Abstract】 Hydrogen Bonding(HB)fluid,being a universal existence in nature,is widely utilized in the fields of physics,chemistry and biology.The structure of HB fluids,though the general behavior of short-ranged order and long-ranged disorder,has its own characteristics,especially on mesoscale.It is well known that osmotic pressure plays a vital role in the process of biological physiology.On the basis of this point of view,it is necessary to understand the aggregation structure and osmotic pressure of complex fluid on mesoscale.Based on the density functional theory(DFT)for classical fluids,fundamental measure theory(FMT)and its modified version,the local structure of colloid and hydrogen bonding(HB)fluid near the semipermeable membrane is studied,where the colloidal particles and HB fluid serve as solute and solvent,respectively.In the present study,the semipermeable membrane allows the passage of solvent molecules but not of solute particles,and therefore,it divides the system into solution and pure solvent or two solutions of different concentration.At first,the grand potential is expressed as a functional of density profile,and then the equilibrium density profile can be obtained by minimizing the grand potential functional.Thereafter,the osmotic pressure of the system is also calculated.Based on these results,the effects of bulk density,the size ratio of two species,HB strength,and functionality on the fluid structure and osmotic pressure are discussed under different conditions.The present dissertation can be divided into three parts,which is listed as follows:Chapter I: Introduction.An introduction to the research background and significance of HB fluid is given in the present dissertation,which includes the characteristics of restricted fluid,the essence and significance of osmotic pressure and HB fluid.Furthermore,the history of DFT for classical fluid is briefly reviewed and its general method for the construction of grand potential functional based on the fundamental measure theory and statistical mechanics is described.Chapter II: Study on structure and osmotic pressure of colloid and HB fluids near a semipermeable membrane.The theoretical model and calculation method are expounded in detail.Based on the DFT,the equilibrium density profiles of the fluids near the semipermeable membrane under various conditions are calculated,and thus the osmotic pressure of the system is calculated according to the equilibrium density distribution.In addition,the effects of hydrogen bonding,bulk density,molecular size ratio on the aggregation structure and osmotic pressure are discussed.Chapter III: The structure of colloid and HB fluids near a semipermeable vesical membrane.The equilibrium density profiles of the fluids near the semipermeable vesical membrane under various conditions are calculated in this chapter.Moreover,the effects of bulk density of two species,molecular size ratio,HB interaction,and the size of vesical membrane on the density profiles are also presented.Chapter IV: Summary.Some conclusions of the investigation of HB fluids on the mesoscale are outlined and the deficiencies for the present study are also pointed out.Furthermore,the potential application of the present research in biology is introduced.It is expected that the investigation of HB fluids on mesoscale could be paid much more attention in the field of biophysics.更多还原