表面张力与溶液浓度函数关系的拟合

在表面活性剂溶液物理化学性质的研究中,经常涉及到溶液表面张力γ与溶液中表面活性剂浓度 C 的对应函数关系问题。比如,在利用 Gibbs 吸附公式:     

溶液表面张力测定实验的改进

采用最大气泡压力法测定溶液的表面张力。与以往实验的不同之处是使用数字式微压差测量仪代替酒精压力计 ,部分实验仪器也有所改进 ,实验的速度和测得数据的精确度均有明显提高。     

最大气泡法测溶液表面张力的改进

用最大气泡法测定不同浓度正丁醇水溶液的表面张力是许多高校开设的物理化学实验之一。该实验要求毛细管底端与待测液面相切 ,操作比较困难 ,而且结果处理比较麻烦 ,且易引入人为误差。本文对该实验进行了改进     

表面活性剂溶液动态表面张力及吸附动力学研究

本文简介了动态表面张力的定义、测定方法及吸附动力学,对非离子、阴离子、阳离子及两性表面活性剂溶液动态表面张力的研究情况进行了总结,重点讨论了浓度、温度、添加剂及化学结构因素对动态表面张力的影响.     

电解质溶液的分子热力学模型研究进展

"本文从经典溶液理论及半经验模型、近代统计力学理论和分子模拟三大方面阐述了近年来国内外电解质溶液热力学的研究进展。指出电解质溶液的研究已逐渐从经典的溶液理论和半经验模型转向用统计力学理论进行研究, 从电解质的原始模型转向非原始模型。从分子和离子的微观参数出发建立高水平的热力学理论模型, 以预测电解质溶液体系的宏观热力学性质, 是发展的必然趋势。     

高分子稀溶液粘度方程中Huggins系数的新解释

高分子稀溶液的粘度常用 Huggins方程 [1] 描述 ,即ηsp/ c=[η] +k H[η] 2 c ( 1 )式中的系数 k H(称为 Huggins系数或斜率常数 )通常认为是一个表征高分子在溶液中的流体力学和热力学相互作用的无量纲数值因子 ,应是一个和分子量无关的常数 .但是早在 50年代初就已发现 ,高分Fig. 1　 Variation of k H with intrinsic viscosity forpolystyrene in toluene or benzene at2 5℃The line is calculated from eq.( 9) with A=5.54andB=0 .0 535for PS in toluene.● PS in benzene;△ oligomeric PS in benzene; PS in toluene;× …     

Wilhelmy吊片法测定磷脂溶液的表面张力等温线

表面活性物质的表面张力等温线测定是大学物理化学实验的重要内容。随着磷脂类表面活性剂的广泛应用,有必要在大学化学中更新经典表面张力等温线测定的实验内容,并使学生掌握先进的测量方法。以二硬脂酰基磷脂酰胆碱(DSPC)和二棕榈酰基磷脂酰胆碱(DPPC)为研究对象,应用界面张力仪测定了两种溶液表面张力等温线,计算了其表面超量和分子横截面积,并设计了拓展性实验内容,对于培养学生分析问题和解决问题的能力具有积极的意义。     

溶液间歇结晶动力学模型的新型算法

针对溶液间歇结晶过程, 基于粒数衡算理论和ΔL定律, 借助分段归纳的研究方法, 建立了晶体粒度分布函数各阶矩量的关联式. 利用此关联式, 对文献模型中晶体粒度分布函数的二阶矩量进行替换, 并结合计算机程序设计, 可直接拟合得到结晶体系的成核和生长动力学参数, 从而为结晶动力学模型的求解建立了一种新型算法. 通过对文献报道的硝酸钾水溶液和混二甲苯溶液两组结晶数据的模拟计算, 结果发现, 运用该算法求取的结晶成核和生长动力学参数均与传统的矩量变换法的计算结果相近, 但新建算法无需预知结晶体系的总传热系数.     

表面活性剂溶液的动表面张力研究

用振荡射流法分别测定了不同温度下全氟辛酸、十二烷基硫酸钠、二聚氯乙烯正辛醇醚溶液(浓度低于CMC)的动表面张力,讨论了它们的表面吸附动力学,研究结果表明都是扩散控制。     

基于电荷平衡的溶液氢离子浓度方程和溶液pH的精确计算

提出了基于电荷平衡的溶液氢离子浓度方程及其方程数值解的溶液pH计算通用方法。解决了一些常见酸碱溶液和复杂酸碱平衡体系的溶液pH计算。     

Dynamic surface tensions of micellar Triton X-100 solutions

Considering surfactant solutions at concentrations exceeding the CMC, another relaxation process besides diffusion occurs, also affecting the dynamic surface tension. The latter equilibration process concerns a micellisation/demicellisation process, representing the disintegration of micelles into monomers. The micellisation kinetics are accounted for by adding a single source term to the diffusion equation of the free monomers.

In the present paper the integration of the diffusion equation is avoided by using the concept of the diffusion penetration depth. Nevertheless, when this approximation is made, good agreement is achieved between experiment and theory for micellar Triton X-100 solutions. Moreover, it follows that diffusion of micelles may not be neglected.     

A New Predictive Equation for the Surface Tensions of Aqueous Mixed Ionic Solutions Conforming to the Linear Isopiestic Relation

The linear isopiestic relation has been used, together with the fundamental Butler equations, to establish a new simple predictive equation for the surface tensions of the mixed ionic solutions. This newly proposed equation can provide the surface tensions of multicomponent solutions using only the data of the corresponding binary subsystems of equal water activity. No binary interaction parameters are required. The predictive capability of the equation has been tested by comparing with the experimental data of the surface tensions for the systems HCl–LiCl–H₂O, HCl–NaClO₄–H₂O, HCl–CaCl₂–H₂O, HCl–SrCl₂–H₂O, HCl–BaCl₂–H₂O, LiCl–NaCl–H₂O, LiCl–KCl–H₂O, NaCl–KCl–H₂O, KNO₃–NH₄NO₃–H₂O, and LiCl–NaCl–KCl–H₂O at 298.15 K; KNO₃–NH₄Cl–H₂O, KBr–Sr(NO₃)₂–H₂O, NaNO₃–Sr(NO₃)₂–H₂O, NaNO₃ –(NH₄)₂SO₄–H₂O, KNO₃–Sr(NO₃)₂– H₂O, NH₄Cl–Sr(NO₃)₂–H₂O, NH₄Cl– (NH₄)₂SO₄–H₂O, KBr–KCl–H₂O, KBr–KCl–NH₄Cl–H₂O, KBr–KNO₃– Sr(NO₃)₂–H₂O, KBr–NH₄Cl–Sr(NO₃)₂–H₂O, KNO₃–NH₄Cl–Sr(NO₃)₂–H₂O, and NH₄Cl–(NH₄)₂SO₄–NaNO₃–H₂O at 291.15 K; and KBr–NaBr–H₂O at temperatures from 283.15 to 308.15 K. The agreement is generally quite good.     

New forms of McKay-Perring equations for mixed electrolyte solutions

Pan, H. and Han, S., 1993. New forms of McKay-Perring equations for mixed electrolyte solutions. Fluid Phase Equilibria, 90: 289-306.

A rigorous derivation is given for new forms of the McKay-Perring equations and the partial differential equation relating the activity coefficients of two electrolytes in mixed electrolyte solutions. They all have simple and symmetrical forms when the independent variables are the total ionic concentration and the fraction of ionic concentration. However, the simple and symmetrical forms remain only when the electrolytes are of the same charge types and when the independent variables are ionic strength and the fraction of ionic strength. The method of surface fitting is introduced to evaluate the McKay-Perring equations. The calculated results for four systems are in good agreement with those from the Pitzer equations.     

有机同系物表面张力递变规律研究

以有机同系物结构重复单元数值连续变化为模型,获得了描述有机同系物表面张力递变规律的数学表达式：σ＝（α0＋α1n＋α2n^2）／（1＋b2n^2）,其中α0,α1,α2,b2均为常数,n为结构重复单元数值,σ为同系物的表面张力,通过非线性回归分析,得到回归方程,结果表明,各类有机同系物的表达张力与重复单元数值满足上述关系式,均显示优良的相关性。     

MEA-CO2-水溶液表面张力实验和模型

用全自动表面张力仪测定了293．15-323．15K温度范围内,具有不同C02载荷的乙醇胺（Monoethanolamine,MEA）水溶液的表面张力,提出了计算MEA-CO2-水体系表面张力的半经验模型,计算结果与实验值吻合良好．通过实验和计算相结合,阐明了温度、MEA浓度和C02载荷对MEA-CO2-水体系表面张力的影响规律．     

Experiments and model for the surface tension of carbonated monoethanolamine aqueous solutions

The surface tension of carbonated monoethanolamine aqueous solutions from 293.15 to 323.15 K was measured by using an automatic surface tension-meter.A model applicable for the surface tension of MEA-CO2-water mixtures was proposed and the calculated results agreed well with the experiments.The influences of temperature,MEA concentration and CO2 loading were demonstrated on the basis of experiments and calculations.     

Stability thresholds of surface phases during electroadsorption of organic compounds from electrolyte solutions

Properties of the interface between a mercury electrode and an electrolytic solution containing surface-active substances are explored. A generalized formulation of conditions for thermodynamic equilibrium during electroadsorption (equation of state) is given with use made of the principle of a minimum free energy of the interface at a zero entropy production (de Donder-Prigogine-Defay). The states on which the second differential of the surface tension is degenerate belong to the stability threshold (lines of inflection points).     

The line tension and the generalized Young equation: the choice of dividing surface

Using Gibbs method of dividing surfaces, the condition of equilibrium of a sessile drop on a flat non-deformable solid substrate is investigated. The dependence of the line tension on the curvature radius of the dividing three-phase contact line is found. It has been derived a relationship between the partial derivative of the line tension with respect to the curvature radius of the three-phase contact line (which stands in the generalized Young equation) and the total derivative of the line tension with respect to the same radius along the equilibrium states. Various approximated formulas of the generalized Young equation used in the literature are analyzed.     

The conductivity of dilute electrolyte solutions: Expanded lee and wheaton equation for symmetrical,unsymmetrical and mixed electrolytes

The conductivity equation of Lee and Wheaton is expanded in a power series in the ionic strength I. Different levels of approximation are analyzed and it is shown that for unsymmetrical electrolytes it is necessary to keep the terms I^3/2lnI and I² to maintain the performance of the full equation.     

A new cubic equation of state for prediction of VLE of polymer solutions

A new cubic equation of state (CEOS) is proposed based on temperature–pressure superposition principle. A generic CEOS form, with the Peng–Robinson parameters, is used and a temperature-dependent attractive term a(T)$a(T)$ is developed, allowing an easy calculation of thermodynamic properties and vapor–liquid equilibrium. The new equation is applied to pure polymer and polymer solutions and its results are compared with those of two others equations of state. For polymer solutions, two mixing rules without binary interaction parameters were used. The vapor–liquid equilibrium (VLE) predictions showed good agreement with experimental data as well as pressure–volume–temperature (PVT) behavior of polymer liquids, attesting the appropriate form of the new equation proposed.