物理化學四大象限之一:Chemical Thermodynamics——從化學熱力學到界面與膠體

物理化學四個主要象限: Molecular Quantum Mechanics / Quantum Chemistry and SpectroscopyStatistical MechanicsChemical Thermodynamics, 以及 Chemical Kinetics and Dynamics, 那麼其中的 Chemical Thermodynamics(化學熱力學) 絕不只是熱力學第一、第二、第三定律而已。

真正完整的化學熱力學,應該從巨觀熱力學基本定律出發, 一路延伸到真實流體、溶液、相平衡、化學平衡、電化學, 最後更進入表面、界面、吸附、膠體、微胞、乳液與潤濕等真實物質系統。

若以三本書共同建立這個象限,可以形成相當漂亮的三級結構:

Fundamental Chemical Thermodynamics

Fluid, Solution & Phase Thermodynamics

Surface, Interface & Colloid Thermodynamics

三本書分別是:

  • Charles E. Reid, Chemical Thermodynamics: 化學熱力學的理論骨架。
  • J. M. Smith, H. C. Van Ness & M. M. Abbott, Introduction to Chemical Engineering Thermodynamics: 真實流體、溶液、相平衡與工程系統。
  • Drew Myers, Surfaces, Interfaces, and Colloids: Principles and Applications: 表面、界面與膠體物理化學。

一、Charles E. Reid《Chemical Thermodynamics》:化學熱力學的理論主幹

Charles E. Reid 的 Chemical Thermodynamics 是一部定位非常純粹的化學熱力學教材。 她以古典熱力學為主要架構, 從基本定律、熱力學勢與平衡條件開始, 逐步進入氣體、熱化學、溶液、化學平衡、相平衡、 電化學與表面熱力學。

書中同時安排了一章 Statistical Thermodynamics, 藉由配分函數與統計觀點說明若干巨觀熱力學結果。 這點也很適合四象限的架構: Chemical Thermodynamics 與 Statistical Mechanics 是不同象限, 卻並不是彼此隔絕。

主要目錄

Chapter 1 — Symbols, Units, and Mathematical Methods

符號、單位與數學方法

  • Symbols and Units
  • Thermodynamic Notation for Partial Derivatives
  • Change of Variable in Differentiation
  • Exact Differentials and Line Integrals
  • Homogeneous Functions

Chapter 2 — Introduction and Basic Laws

導論與熱力學基本定律

  • Basic Definitions
  • The First Law of Thermodynamics
  • The Enthalpy
  • Thermal Equilibrium
  • Reversible and Irreversible Changes
  • Intensive and Extensive Properties
  • The Second Law
  • The Carnot Cycle
  • Consequences of the Second Law

這一部分建立古典熱力學最基本的語言: 內能 U、焓 H、熱、功、熵以及可逆與不可逆過程。

Chapter 3 — Equilibrium and the Free Energy Functions

平衡與自由能函數

  • Equilibrium at Constant Energy and Volume
  • Equilibrium at Constant Temperature and Volume
  • Equilibrium at Constant Temperature and Pressure
  • Thermodynamic Potentials
  • Stable, Metastable, Unstable, and Neutral Equilibria

從這一章開始,熱力學真正成為「決定變化方向與平衡」的理論。 不同限制條件下,系統分別以適當的熱力學勢作為平衡判準:

U、H、A、G

Chapter 4 — Gases

氣體

  • Pressure–Volume Relations in Gases
  • The Ideal Gas
  • The Gas Constant
  • Nonideal Gases
  • Standard States
  • Fugacities of Liquids and Solids
  • Equations of State for Real Gases
  • The Principle of Corresponding States
  • The van der Waals Equation
  • The Clapeyron Equation

Chapter 5 — Introduction to Thermochemistry

熱化學導論

  • Thermodynamic Property Changes in a Reaction
  • Calorimetry
  • Determination of Enthalpy Change
  • Kirchhoff Equation
  • Enthalpies of Combustion
  • Bond Enthalpies
  • Electron Affinities and Crystal Energies
  • Entropies of Reaction
  • The Third Law

因此「化學反應的能量學」本身就是 Chemical Thermodynamics 的核心內容。

Chapter 6 — Statistical Thermodynamics

統計熱力學

  • General Principles and Definitions
  • The Boltzmann H-Theorem
  • The Entropy Postulate
  • The Distribution of Systems in Equilibrium
  • Partition Function and Thermodynamic Properties
  • The Einstein Crystal Model
  • Factorization of the Partition Function
  • The Ideal Monatomic Gas
  • Diatomic and Polyatomic Gases
  • The Debye Crystal Model
  • Planck's Radiation Equation
  • Statistical Thermodynamics and the Third Law

在四象限分類下,這一章最適合看作 Statistical Mechanics → Chemical Thermodynamics 之間的橋梁。

Chapter 7 — Mixtures and Solutions

混合物與溶液

  • The Chemical Potential
  • Partial Molar Quantities
  • The Gibbs–Duhem Equation
  • Ideal Mixtures
  • Nonideal Mixtures
  • Rational Activities
  • Solvent and Solute Activities
  • Osmotic Coefficients
  • Molal Activity Scale

這裡出現化學熱力學最重要的變數之一:

chemical potential,μi

有了化學勢,熱力學才真正能夠系統處理多成分化學系統。

Chapter 8 — Chemical Equilibrium and Phase Equilibrium

化學平衡與相平衡

  • Fundamental Equilibrium Expression for a Chemical Reaction
  • The Equilibrium Constant
  • Variation of Equilibrium Constant with Temperature
  • Statistical Mechanics of Chemical Equilibrium
  • Phase Equilibrium in Nonreacting Systems
  • The Phase Rule
  • The Phase Rule for Reacting Systems
  • Partially Miscible Binary Liquid Systems

Chapter 9 — The Thermochemistry of Solutions

溶液熱化學

  • Enthalpies of Solution
  • Enthalpies of Formation of Ions
  • Experimental Measurement

Chapter 10 — Electrolytic Solutions and Electrochemical Cells

電解質溶液與電化學電池

  • Chemical Potentials, Activities, and Activity Coefficients
  • Debye–Hückel Limiting Law
  • Electrolyte Activities
  • Galvanic Cells
  • Electrode Potentials
  • Electrochemical Potentials

所以在這個分類中, Electrochemistry 可以自然視為 Chemical Thermodynamics 的重要分支。

Chapter 11 — Thermodynamics of Surfaces and Gravitational Fields

表面與重力場的熱力學

  • General Consideration of Surfaces
  • Equilibrium Conditions for the Surface
  • Capillary Rise
  • Thermal Effects of Increasing the Surface
  • Gibbs Equation for Adsorption at a Surface
  • Thermodynamics in a Gravitational Field

這一章尤其重要,因為她已經從普通 bulk thermodynamics 伸手進入 Surface Thermodynamics。 而這正是後面 Drew Myers 那本書要大幅展開的領域。

Chapter 12 — Systematic Methods of Deriving Thermodynamic Relations

熱力學關係的系統推導方法

  • Jacobians
  • Systems of Constant Composition
  • Shaw's Formulation
  • The Bridgman Tables
  • Transformation Methods

二、Smith、Van Ness、Abbott:把化學熱力學推向真實流體與工程系統

如果 Reid 的書回答的是:

化學熱力學的理論結構是什麼?

那麼 Smith、Van Ness 與 Abbott 的 Introduction to Chemical Engineering Thermodynamics 處理的問題便更接近:

真正的氣體、液體、混合物與化工程序,要怎麼算?

作者在序言中明確指出,本書從 chemical-engineering viewpoint 處理 thermodynamics, 但仍然強調建立在嚴謹熱力學原理之上。

核心內容

Chapter 1 — Introduction

  • Scope of Thermodynamics
  • Dimensions and Units
  • Temperature
  • Pressure
  • Work
  • Energy
  • Heat

Chapter 2 — The First Law and Other Basic Concepts

  • Internal Energy
  • The First Law
  • Energy Balances
  • Thermodynamic State
  • Equilibrium
  • Phase Rule
  • Reversible Process
  • Enthalpy
  • Heat Capacity
  • Open-System Mass and Energy Balances

和一般化學系物化教材相比, 這裡很早便正式納入 open systems

Chapter 3 — Volumetric Properties of Pure Fluids

純流體體積性質

  • PVT Behavior
  • Virial Equations
  • Ideal Gas
  • Cubic Equations of State
  • Generalized Correlations

這一章開始把 Chemical Thermodynamics 推到真正的 real-fluid thermodynamics

Chapter 4 — Heat Effects

熱效應

  • Sensible Heat Effects
  • Latent Heats
  • Standard Heat of Reaction
  • Standard Heat of Formation
  • Standard Heat of Combustion
  • Industrial Reaction Heat Effects

Chapter 5 — The Second Law of Thermodynamics

  • Heat Engines
  • Entropy
  • Entropy Balance for Open Systems
  • Ideal Work
  • Lost Work
  • The Third Law
  • Microscopic View of Entropy

Chapter 6 — Thermodynamic Properties of Fluids

  • Property Relations
  • Residual Properties
  • Equations of State
  • Two-Phase Systems
  • Thermodynamic Diagrams and Tables

Chapter 7 — Applications of Thermodynamics to Flow Processes

  • Duct Flow
  • Turbines
  • Expanders
  • Compression Processes

這裡雖然涉及流動, 但其核心仍然是能量、熵與狀態性質; 因此和真正以動量、熱量、質量傳遞為核心的 Transport Phenomena 仍可區分。

Chapter 8 — Production of Power from Heat

  • Steam Power Plants
  • Internal-Combustion Engines
  • Jet and Related Power Cycles

Chapter 9 — Refrigeration and Liquefaction

  • Refrigeration Cycles
  • Vapor Compression
  • Heat Pumps
  • Liquefaction Processes

Chapter 10 — Vapor/Liquid Equilibrium: Introduction

汽液平衡

  • Nature of Equilibrium
  • Phase Rule
  • Duhem's Theorem
  • Simple VLE Models
  • Modified Raoult's Law
  • K-Value Correlations

Chapter 11 — Solution Thermodynamics: Theory

  • Fundamental Property Relation
  • Chemical Potential
  • Partial Properties
  • Fugacity
  • Fugacity Coefficients
  • Ideal Solutions
  • Excess Properties

在這裡,現代相平衡最重要的一套語言正式出現:

μi + fi + γi + φi

Chapter 12 — Solution Thermodynamics: Applications

  • Liquid-Phase Properties from VLE Data
  • Excess Gibbs-Energy Models
  • Properties of Mixing
  • Heat Effects of Mixing

Chapter 13 — Chemical-Reaction Equilibria

  • Reaction Coordinate
  • Equilibrium Criteria
  • Standard Gibbs-Energy Change
  • Equilibrium Constant
  • Temperature Dependence
  • Equilibrium Conversion
  • Multireaction Equilibria
  • Fuel Cells

ΔrG = ΔrG° + RT ln Q

而平衡時:

ΔrG = 0

Chapter 14 — Topics in Phase Equilibria

  • γ/φ Formulation of VLE
  • VLE from Cubic Equations of State
  • Phase Stability
  • Liquid/Liquid Equilibrium
  • Vapor/Liquid/Liquid Equilibrium
  • Solid/Liquid Equilibrium
  • Solid/Vapor Equilibrium
  • Gas Adsorption on Solids
  • Osmotic Equilibrium

Chapter 15 — Thermodynamic Analysis of Processes

將第一、第二定律以及 irreversibility 正式用來分析真實化工程序。

Chapter 16 — Introduction to Molecular Thermodynamics

  • Molecular Theory of Fluids
  • Intermolecular Potential Functions
  • Virial Coefficients
  • Statistical Mechanics
  • Hydrogen Bonding
  • Molecular Basis of Mixture Behavior
  • Molecular Simulation of VLE

這一章又重新接回 Statistical Mechanics:

Intermolecular Potential

Statistical Mechanics

Equation of State

Phase Equilibrium

三、Drew Myers《Surfaces, Interfaces, and Colloids》:從體相走向真正的界面世界

加入 Drew Myers 的 Surfaces, Interfaces, and Colloids: Principles and Applications 之後,Chemical Thermodynamics 這一象限便不再停留於 bulk fluid、solution 與 phase equilibrium, 而正式進入:

Surface → Interface → Colloid → Self-Assembly

Myers 把表面與膠體稱為介於分子尺度與巨觀體相之間的 「被忽略的尺度」, 甚至以 Twilight Zone 形容這個領域。

更重要的是,這本書不是單純列舉各種膠體現象; 她把整個領域建立在 surface free energy、intermolecular forces、electrostatics、 adsorption、thermodynamics 與 kinetics 之上。

Chapter 1 — Surfaces and Colloids: The Twilight Zone

表面與膠體:介於分子與體相之間的世界

膠體與界面位於兩個極端之間:

Molecule / Atom  ↔  Interface / Colloid  ↔  Bulk Matter

這也是非常典型的 mesoscopic science: 某些性質只有在大量分子、粒子與界面共同作用時才會出現。

Chapter 2 — Surfaces and Interfaces: General Concepts

  • The Nature of Interfaces
  • Surface Free Energy
  • Work of Cohesion
  • Work of Adhesion
  • Standard Reference States
  • Molecular Nature of the Interfacial Region

這裡是整本書最核心的熱力學起點。 形成新的界面需要增加系統自由能,可以概念性寫成:

dG = γ dA

其中 γ 表示單位界面面積所對應的自由能代價。 因此,自然系統通常傾向降低總界面面積。

對平衡純液體而言, surface tension 與 specific excess surface free energy 具有密切而直接的關係; 但對固體而言,由於晶體方向性、表面缺陷與非平衡性, surface energy 與 surface stress 的關係更加複雜。

Chapter 3 — Surface Activity and Surfactant Structures

  • Surface Activity
  • Hydrophilic and Hydrophobic Groups
  • Anionic Surfactants
  • Cationic Surfactants
  • Nonionic Surfactants
  • Amphoteric and Zwitterionic Surfactants

界面活性劑的 amphiphilic 結構, 使分子可以透過吸附於界面或形成聚集體降低系統自由能。

Surfactant in Solution → Adsorption / Aggregation → Lower Free Energy

Chapter 4 — Attractive Forces

  • Coulombic Interactions
  • Ion–Dipole Interactions
  • Dipole–Dipole Interactions
  • Dipole-Induced Dipole Interactions
  • London Dispersion Forces
  • Total van der Waals Interactions
  • Hamaker Theory
  • Lifshitz Theory

這一章很漂亮地把 Chemical Thermodynamics 接回 Quantum Chemistry。

其中 London dispersion force 本質上來自量子力學, 而在介面與膠體系統中, 大量分子之間的相互作用又會形成巨觀可測量的表面與膠體性質:

Quantum Mechanics

Intermolecular Forces

Surface Free Energy

Interfacial / Colloidal Properties

Chapter 5 — Electrostatic Forces and the Electrical Double Layer

  • Sources of Interfacial Charge
  • Coulomb's Law
  • Boltzmann Distribution
  • Electrical Double Layer
  • Debye Length
  • Stern Layer
  • Electrophoresis
  • Electrokinetic Phenomena

這一部分其實是三種理論的交叉:

Electromagnetism + Statistical Mechanics + Chemical Thermodynamics

然後產生電雙層、Debye screening、 electrophoresis 等典型界面現象。

Chapter 6 — Capillarity

  • Capillary Forces
  • Contact Angle
  • Capillary Flow
  • Spreading
  • Wetting

這裡可以看到表面自由能如何直接轉化成肉眼可見的巨觀現象。

Chapter 7 — Solid Surfaces

  • Surface Mobility in Solids
  • Sintering
  • Solid Surface Free Energy
  • Crystalline Surfaces
  • Nucleation
  • Amorphous Solid Surfaces

因此 Surface Thermodynamics 又自然與 solid-state chemistry、materials science 以及 condensed matter 相連。

Chapter 8 — Liquid–Fluid Interfaces

  • Surface Tension
  • Temperature Effects
  • Surface Curvature
  • Dynamic Surface Tension
  • Surfactant Adsorption
  • Gibbs Monolayers
  • Surface Pressure
  • Surface Potential
  • Surface Rheology

這一章幾乎就是完整的 Interfacial Thermodynamics

Chapter 9 — Adsorption

  • Gibbs Surface Excess
  • Gibbs Adsorption Equation
  • Physical Adsorption
  • Chemisorption
  • Heterogeneous Catalysis
  • Langmuir Isotherm
  • Freundlich Isotherm
  • BET Isotherm
  • Solid–Liquid Adsorption

Reid 書中較精簡的 Gibbs surface thermodynamics, 到了 Myers 這裡被真正展開成完整的 adsorption science。

Chapter 10 — Colloids and Colloidal Stability

  • Colloid Formation
  • Interparticle Forces
  • Electrical Double Layer
  • Steric Stabilization
  • Coagulation Kinetics
  • DLVO Theory
  • Reversible Flocculation

「膠體穩定性」是一種非常典型的集體性質。 單獨一顆粒子並不存在 colloidal stability 的問題; 當大量粒子與溶劑、離子以及界面共同存在時, 才會湧現出聚集、排斥、穩定與絮凝等行為。

Chapter 11 — Emulsions

  • Emulsion Formation
  • Liquid–Liquid Interfaces
  • Emulsifiers and Stabilizers
  • Surfactants
  • Hydrophile–Lipophile Balance
  • Phase Inversion Temperature
  • Multiple Emulsions

Chapter 12 — Foams

  • Foam Formation
  • Thermodynamic Conditions for Stability
  • Stabilization Mechanisms
  • Surface Rheology
  • Surfactant Effects

Chapter 13 — Aerosols

  • Aerosol Dynamics
  • Mists and Fogs
  • Droplet Formation
  • Atomization
  • Dust and Smoke

此處已開始與 Fluid Mechanics 以及 Transport Phenomena 產生明顯交界。

Chapter 14 — Polymers at Interfaces

  • Polymer Solubility
  • Statistics of Polymer Chain Conformations
  • Polymer Adsorption
  • Polymer–Surfactant Interactions
  • Emulsion Polymerization

這又形成:

Statistical Mechanics + Polymer Physics + Surface Chemistry

Chapter 15 — Association Colloids: Micelles, Vesicles, and Membranes

  • Krafft Temperature
  • Surfactant Liquid Crystals
  • Micelles
  • Thermodynamics of Micelle Formation
  • Free Energy of Micellization
  • Critical Micelle Concentration
  • Vesicles
  • Bilayer Membranes
  • Biological Membranes

這其實就是典型的 self-assembly thermodynamics

Monomers ⇌ Micelle / Vesicle / Bilayer

分子不是靠共價鍵連成一個新分子, 而是透過自由能、熵與分子間作用力, 自行組織成新的巨觀或介觀結構。

Chapter 16 — Solubilization, Micellar Catalysis, and Microemulsions

  • Solubilization
  • Micellar Catalysis
  • Microemulsions
  • Interfacial Tension

Chapter 17 — Wetting and Spreading

  • Contact Angle
  • Contact Angle Hysteresis
  • Surface Roughness
  • Thermodynamics of Wetting
  • Young's Equation
  • Spreading Coefficient
  • Solid Surface Energy
  • Dynamic Wetting

Young equation 可以寫成:

γSV = γSL + γLV cos θ

這幾乎可以算是界面熱力學最具代表性的方程之一。

Chapter 18 — Friction, Lubrication, and Wear

  • Friction
  • Surface Structure
  • Lubrication
  • Adsorption
  • Wear

這裡則開始與 tribology、 materials science 與 fluid mechanics 相交。

Chapter 19 — Adhesion

  • Thermodynamic Adhesion
  • Practical Adhesion
  • Adhesive Failure

整本書最後又回到 Chapter 2 的基本問題: 不同物質形成或分離一個界面,需要多少自由能?

四、三本書共同構成的 Chemical Thermodynamics

層次 代表教材 核心內容
Fundamental Chemical Thermodynamics Charles E. Reid U、H、S、A、G、chemical potential、equilibrium、thermochemistry、 electrochemistry
Fluid, Solution & Phase Thermodynamics Smith、Van Ness、Abbott Real fluids、EOS、fugacity、activity、 VLE、LLE、chemical equilibrium、process thermodynamics
Surface, Interface & Colloid Thermodynamics Drew Myers Surface free energy、adsorption、double layer、wetting、 colloids、micelles、emulsions、foams、membranes、adhesion

五、從 Bulk 到 Interface:這才是完整的化學熱力學

如果只按照一般基礎物理化學教材的篇幅, Chemical Thermodynamics 很容易被看成:

第一定律 + 第二定律 + 自由能 + 平衡

但三本專書合起來以後, 真正的版圖其實是:

Thermodynamic Laws

Thermodynamic Potentials

Chemical Potential

Real Fluids & Equations of State

Mixtures & Solutions

Chemical & Phase Equilibria

Electrochemistry

Surface Free Energy

Adsorption & Wetting

Colloids & Self-Assembly

六、Chemical Thermodynamics 與其他三象限並不是互不往來

這三本書同時還證明了一件很重要的事: 四大象限不是四個互相隔離的抽屜。

與 Statistical Mechanics 的交界

Reid 有 Statistical Thermodynamics; Smith–Van Ness–Abbott 最後進入 Molecular Thermodynamics; Myers 在微胞、高分子與膠體中大量涉及 Boltzmann distribution、entropy 與 molecular organization。

Statistical Mechanics → Macroscopic Thermodynamic Properties

與 Quantum Chemistry 的交界

Myers 討論的 London dispersion force 本質上具有量子力學來源, 而分子間作用力又進一步控制吸附、 凝聚、膠體穩定與自組裝。

Quantum Chemistry → Intermolecular Forces → Interfacial Properties

與 Chemical Kinetics and Dynamics 的交界

膠體絮凝、潤濕、吸附、乳液破壞、 表面反應與異相催化都不只需要知道 「最後哪個狀態最穩定」, 還必須知道:

系統多久才會走到那裡?

也就是:

Thermodynamics tells us where.
Kinetics tells us how fast.

結論:Chemical Thermodynamics 是物質巨觀行為的理論

因此,在這套物理化學四大象限裡, Chemical Thermodynamics 最適合被理解為:

研究大量粒子所形成之巨觀與介觀化學系統, 其能量、熵、組成、相態、平衡以及界面行為的理論。

她從最基本的:

U、H、S、A、G、μ

一路走到:

氣體、液體、溶液、混合物、相平衡、反應平衡、 電化學、表面、界面、吸附、膠體、乳液、微胞與膜

於是這個象限可以完整寫成:

Chemical Thermodynamics

Thermodynamic Laws
+ Thermochemistry
+ Fluid Thermodynamics
+ Solution Thermodynamics
+ Chemical Potential
+ Phase Equilibria
+ Chemical Equilibria
+ Electrochemistry
+ Surface & Interfacial Thermodynamics
+ Colloid Thermodynamics
+ Self-Assembly Thermodynamics
+ Process Thermodynamics

如此一來, Chemical Thermodynamics 就不再只是「熱與功的學問」, 而是從 bulk matter 一直延伸到 interface, 用自由能與統計觀念回答: 大量物質為什麼呈現現在這個狀態,又為什麼會朝另一個狀態改變。

而她與 Molecular Quantum Mechanics、 Statistical Mechanics、 Chemical Kinetics and Dynamics 一起, 才真正構成一套完整的物理化學理論架構。