The chemistry and physics of aerogels : synthesis, processing, and properties / Lorenz Ratke, German Aerospace Center, Pavel Gurikov, Hamburg University of Technology.

Format:

Book

Author/Creator:

Ratke, Lorenz, 1949- author.

Gurikov, Pavel, 1983- author.

Language:

English

Subjects (All):

Aerogels.

Polymer colloids.

Physical Description:

1 online resource (xiv, 471 pages) : digital, PDF file(s).

Edition:

1st ed.

Place of Publication:

Cambridge : Cambridge University Press, 2021.

Summary:

Discover a rigorous treatment of aerogels processing and techniques for characterization with this easy-to-use reference. Presents the basics of aerogel synthesis and gelation to open porous nanostructures, and the processing of wet gels like ambient and supercritical drying leading to aerogels. Describes their essential properties with their measurement techniques and theoretical models used to analyse relations to their nanostructure. Linking the fundamentals and with practical applications, this is a useful toolkit for advanced undergraduates, and graduate students doing research in material and polymer science, physical chemistry, and chemical and environmental engineering.

Contents:

Cover

Half-title

Title page

Copyright information

Dedication

Contents

Preface

1 Introduction

1.1 What Exactly Is an Aerogel?

1.2 Aerogel Classification

1.3 A Brief History of Aerogels

2 Chemical Synthesis of Aerogels from Monomeric Precursors

2.1 Silica Aerogels

2.1.1 Silica Aerogel Precursors

2.1.2 Monomeric Precurors

2.1.3 Hydrolysis and Polycondensation

2.1.4 Growth and Structure

2.1.5 Gelation

2.1.6 Ageing

2.1.7 Procedures and Results

2.1.8 Silica Aerogels with Lower Functional Silanes

2.2 Resorcinol-Formaldehyde Aerogels

2.2.1 Chemistry of Resorcinol and Formaldehyde

2.2.2 Reaction between Resorcinol and Formaldehyde

2.2.3 From Monomers to Polymers

2.2.4 Parameters of Synthesis

2.2.5 Thermodynamics of RF Solutions

2.3 Variables and Symbols

3 Chemical Synthesis of Aerogels from Polymeric Precursors

3.1 Synthesis of Cellulose Aerogels

3.1.1 Dissolution Agents for Cellulose

3.1.2 Gelation of Cellulose Solutions

3.1.3 Preparation of Bulky Cellulose Aerogels

3.2 Alginate: From Solution to Gel

3.2.1 Structure of Alginate

3.2.2 Degradation and Chemical Modifications

3.2.3 Gelation of Alginate

3.3 Variables and Symbols

4 Gelation

4.1 Viscosity of Gelling Solutions

4.1.1 Simple Models of Viscoelasticity

4.1.2 Evolution of Viscosity during Gelation

4.1.3 Tilting as a Simple Measure of Gelation

4.1.4 Rotating Bob Viscosimeter

4.1.5 Flow Damping

4.1.6 Light Transmission and Scattering

4.2 Theoretical Descriptions of Gelation

4.2.1 Percolation and Fractals

4.2.2 Diffusion-Limited Aggregation - DLA and DLCA

4.2.3 Mean Field Model of Smoluchowski

4.2.4 Scaling Solutions and Gelation

4.2.5 Polymerisation-Induced Phase Separation (PIPS)

4.3 Predictions of Gel Time

4.3.1 Gelation by Aggregation.

4.3.2 Family-Viscek Scaling for Gel Times

4.3.3 Gel Time Prediction by PIPS

4.4 Variables and Symbols

5 Drying of Wet Gels

5.1 Ambient Drying

5.1.1 Some Observations during Drying

5.1.2 Evaporation Rate

5.1.3 Capillary Stress and Vapour Pressure

5.1.4 Flow of Fluid and Gas in the Network during Drying

5.2 Freeze Drying

5.2.1 Freezing of Single-Component Liquid

5.2.2 Freezing of a Multicomponent Liquid

5.2.3 Freezing of a Gel Liquid

5.2.4 Sublimation

5.3 Supercritical Drying

5.3.1 Supercritical Fluids

5.3.2 High-Temperature Supercritical Drying

5.3.3 Rapid Supercritical Extraction

5.3.4 Low-Temperature Supercritical Drying

5.4 Solvent Exchange and Gel Shrinkage

5.4.1 Solvent Selection

5.4.2 Gel Shrinkage: General Considerations

5.4.3 Gel-Solvent Interactions

5.4.4 Minimising Gel Shrinkage

5.5 Variables and Symbols

6 Morphology of Aerogels

6.1 Imaging Techniques

6.1.1 Scanning Electron Microscopy

6.1.2 Transmission Electron Microscopy

6.2 TEM Images of Aerogels

6.3 SEM Images of Particular Aerogels

6.4 SEM Images of Fibrillar Structures

7 Density: Models and Measures

7.1 Measurement of Envelope Density

7.2 Measurement of Skeletal Density

7.2.1 Measurement Principle

7.2.2 Effect of Adsorbates

7.2.3 Pressure Evolution

7.2.4 Effect of Test Gas on Skeletal Density

7.3 Porosity

7.4 Rule of Mixtures for the Envelope Density

7.5 Relation between Monomer Content and Final Density

7.5.1 Estimate of the Envelope Density of Silica Aerogels

7.5.2 Estimate of the Envelope Density of RF Aerogels

7.5.3 Density of Cellulose Aerogels

7.6 Variables and Symbols

8 Specific Surface Area

8.1 Definitions and Relations

8.2 Surface Area of Simple Shapes

8.3 Surface Area of Irregular-Shaped Bodies.

8.4 Surface Area of Fibrillar Aerogels

8.5 Surface Area of Aerogel Composites

8.6 Measurement of Specific Surface Area

8.6.1 Langmuir Isotherm

8.6.2 A Bit of Thermodynamics of Adsorption

8.6.3 BET Isotherm

8.6.4 T-plot

8.6.5 Small Angle X-Ray Scattering (SAXS)

8.7 Variables and Symbols

9 Pores and Pore Sizes

9.1 Simple Geometrical Models

9.2 Stereological Pore Size Description

9.2.1 Pore Size Distribution: The BJH Method

9.2.2 Pore Size Distribution: Thermoporosimetry

9.3 Variables and Symbols

10 Diffusion in Aerogels

10.1 A Phenomenological Approach to Diffusion

10.2 Diffusion Coefficients

10.2.1 Knudsen Diffusion

10.3 Measurement of Gas Diffusion in Aerogels

10.4 Variables and Symbols

11 Permeability for Gases

11.1 An Experimental Approach

11.1.1 A Dynamic Measurement Setup

11.1.2 Stationary Measurement of Permeability

11.2 Full Mathematical Model of Porous Media

11.2.1 Characteristic Time of Permeation

11.2.2 Stationary State

11.2.3 Reynolds Number

11.3 Flow through an Aerogel

11.4 Knudsen Effect

11.5 The Meaning of Permeability

11.5.1 Parallel Cylindrical Pore Arrangement

11.5.2 Karman-Kozeny Permeability

11.6 Permeability of Some Aerogels

11.7 Variables and Symbols

12 Thermal Properties

12.1 Heat Conduction Equation

12.2 Heat Conduction in Porous Materials: Aerogels

12.2.1 Porous Media in General

12.3 Thermal Conductivity of Aerogels

12.3.1 Heat Conduction of the Solid Backbone

12.3.2 Gas Phase Transport of Heat

12.3.3 Radiative Heat Transport

12.4 Thermal Diffusivity

12.4.1 Specific Heat Capacity

12.5 Measurement Techniques of Thermal Properties of Aerogels

12.5.1 Stationary Measurement Methods

12.5.2 In-Stationary Measurement Methods

12.6 Application of Aerogels to Insulation Tasks.

12.6.1 Transfer of Heat from a Plate into the Surrounding Medium

12.6.2 The Solution

12.6.3 Stationary Case

12.6.4 Instationary Case

12.6.5 Heat Transfer from a Tube through an Insulation

12.6.6 Stationary Solution for a Cylindrical Shell

12.7 Variables and Symbols

13 Mechanical Properties of Aerogels

13.1 Mechanical Testing: A Brief Introduction

13.1.1 Bending

13.1.2 Compression Test

13.1.3 Tension and Brazilian Test

13.1.4 Flexibility

13.1.5 Compressibility

13.1.6 Young's Modulus from Sound Velocity Measurement

13.2 Stress-Strain Curves of Aerogels

13.3 Young's Modulus of Aerogels

13.3.1 The Gibson and Ashby (GA) Model for Porous Materials

13.3.2 Simple Extensions of the GA Model for Aerogels

13.3.3 Experimental Results

13.4 Yield and Fracture Strength of Aerogels

13.5 Modelling of the Mechanical Response of Aerogels

13.5.1 A Model for Compressive Stress-Strain Curves

13.6 Variables and Symbols

14 How to Cook Aerogels: Recipes and Procedures

14.1 Silica Aerogels

14.1.1 Classical Silica Aerogel

14.1.2 A Superflexible Silica Aerogel

14.2 Cellulose Aerogels

14.3 Alginate Aerogel Beads

14.4 Resorcinol-Formaldehyde Aerogels/Xerogels

Appendix A Thermodynamics and Phase Separation in Immiscibles

A.1 A Bit of Thermodynamics

A.1.1 Ideal and Regular Solutions

A.2 Phase Separation in a Regular Solution

A.2.1 Phase Separation by Nucleation and Growth

A.2.2 Phase Separation by Spinodal Decomposition

Appendix B Flory-Huggins Theory of Polymer Solutions

Appendix C A Brief Review on Scattering

C.1 Form Factor

C.2 Structure Factor

C.3 Specific Surface Area

C.4 Dynamic Light Scattering

Appendix D Mathematics of Polycondensation

D.1 A Simple Model of a Bimolecular Reaction

D.2 A More Complex Model of Polycondensation.

D.2.1 A Variant of Smoluchowski's Aggregation Equation

D.2.2 Degree of Polymerisation

D.2.3 Flory-Schulz Distribution

D.2.4 Global Volume Fraction Polymers

D.2.5 The Maximum Volume Fraction Polymer

Appendix E Time-Dependent Heat Transfer through an Isolated Tube

References

Index.

Notes:

Title from publisher's bibliographic system (viewed on 03 Dec 2021).

ISBN:

1-108-80540-X

1-108-77833-X

OCLC:

1298388160