Colloid Science Vol. 1

274 Pages·1973·16.88 MB·English

A Specialist Periodical Report
Colloid Science
Volume 1
A Review of the Literature Published during
1970 and 1971
Senior Reporter
D. H. Everett, M.B.E., Department of Physical Chemistry,
Universify of Bristol
Re porters
S. G. Ash, Thornfon Research Cenfre, Chesfer
J. M. Haynes, Universify of Brisfol
R. H. Ottewill, Universify of Brisfol
K. S.W . Sing, Brunel Universify
B. Vincent, Universify of Bristol
0 Copyright 1973
The Chemical Society
Burlington House, London WIV OBN
ISBN : 0 85186 508 9
Library of Congress Catalog Card No. 72-95096
Printed in Great Britain by
Adlard & Son Ltd.
Bartholomew Press, Dorking
Preface
The initiation of any new series of progress reports in science involves a
number of policy decisions. The first concerns the choice of a convenient date
from which to commence a detailed literature survey, and the second, the
extent to which earlier work should be incorporated. Most of the chapters
in this first volume cover the literature from late 1969 to the end of 1971.
However, it is not feasible to give a useful account of recent progress without
assessing the state of development of the subject at the start of the period
under review. This has been achieved in some cases by reference to earlier
review articles, but in several instances it has been considered desirable to
give a much fuller introductory exposition. In part, at least, the need to
prepare a number of basic reviews before describing recent work has made
the interval between the end of the period covered and publication longer
than desirable; it is hoped to rectify this in subsequent volumes.
Additional problems arise in a field as diverse as that of Colloid Science,
where it is difficult, and in some ways undesirable, to defme the boundaries
of the subject too sharply. The number and range of journals in which relevant
work is published then makes it difficult to ensure complete coverage. The
primary bibliography for the present volume has been drawn from Chemical
Abstracts, despite certain shortcomings in the coverage of fringe areas, and
the inevitable delay which reliance on an abstract journal involves.
The scientific principles underlying Colloid Science are in some cases not
firmly established and an important function of reports such as this is to attempt
a critical assessment of new ideas so that readers can make a considered
judgment of their relevance and importance. At the same time an essentially
complete bibliography of related but less fundamental papers is often of
considerable value. Some balance of treatment has been aimed at: the reader
may judge the adequacy of the resultant text for his particular needs.
It is clearly impossible to review the whole of Colloid Science in one
volume. The first volume, therefore, deals with a selected group of topics
which will be supplemented in the second and subsequent volumes to cover
most of the important areas of Colloid Science. Certain of the major fields
of endeavour will be reviewed in each volume, while others will be dealt with
at longer intervals.
iv Preface
To assist the reporters in ensuring the widest possible coverage, and to
avoid delays arising from the need to search abstracts, authors are invited
to forward reprints of their relevant papers to the Senior Reporter, Specialist
Periodical Report on Colloid Science, School of Chemistry, Bristol BS8 lTS,
England.
Bristol, June 1973 D. H. Everett
Cont ents
Chapter 1 Adsorption at the Gas/Solid Interface
By K. S. W. Sing
1 Introduction 1
2 The Adsorption Potential 3
Adsorbate-Adsorbent Interactions on Non-porous Solids 3
3 Adsorbate-Adsorbent Interactions on Microporous Solids 10
4 Adsorbate-Adsorbate Interactions 17
5 The Adsorption Isotherm 21
Experimental Methods 21
The Isotherm at Low Surface Coverage 22
Henry’s Law 22
The Virial Equation 26
The Dubinin-Radushkevich-Kaganer Equation 29
The Isotherm at High Surface Coverage 30
The Hill-de Boer Equation and Two-dimensional
Condensation 30
Localized Adsorption and the Langmuir Equation 34
6 The Brunauer-Emmett-Teller Equation and the
Determination of Surface Area 38
7 Empirical Methods for Isotherm Analysis 42
Chapter 2 Adsorption at the Solid/Liquid Interface: Mon-aqueous
Systems
By D. H. Everetf
1 Introduction 49
2 Thermodynamic and Statistical Mechanical Studies :
Monolayer Model 61
3 The Validity of the Monolayer Model 66
4 Statistical Mechanical Studies: Multilayer Model 70
vi Contents
5 Determination of Surface Areas from Adsorption from
Solution 76
6 Some Alternative Theoretical Treatments 81
Polanyi Potential Theory 81
Significant Structures Theory 86
7 Studies of Specific Systems 88
8 Adsorption from Multicomponent Systems 101
Chapter 3 Polymer Adsorption at the Solid/Liquid Interface
By S. G. Ash
1 Introduction 103
2 Theory 104
3 Experimental Techniques 108
I.R. Spectroscopy 109
N.M.R. and E.S.R. Spectroscopy 109
Ellipsometry 109
Hydrodynamic Barrier Thickness 109
4 Experimental Results 110
Adsorption Isotherm 110
Influence of Molecular Weight 111
Non-porous Adsorbents 111
Porous Adsorbents 113
Influence of Polymer Structure 113
Influence of Tacticity 114
Influence of Solvent 114
Influence of Adsorbent 118
Competition between Polymers 119
Adsorption Kinetics 12 0
Chapter 4 Capillarity and Porous Materials: Equilibrium
Properties
By D. H. Everett and J. M. Haynes
1 Introduction 123
2 Adsorption Energies in Pores 125
3 Fundamental Theory of Capillary Condensation 125
Contents vii
4 Range of Stability of Capillary-condensed Liquid 131
5 Model Capillary Systems 136
6 Calculation of Pore-size Distributions from Experimental
Data 140
7 Mercury Porosimetry 149
8 Phase Changes in Adsorbed Materials 155
9 Preparation and Properties of Specific Porous Media 159
AIumina 159
Silica 16 0
Other Oxides 162
Mixed Oxides 164
Clays and Zeolites 167
Carbon 168
Other Materials 171
Chapter 5 Particulate Dispersions
By R. H. Oftewifl
1 Introduction 173
2 van der Waals Interactions 176
Direct Measurement of Attractive Forces 183
3 Forces of Electrostatic Origin 185
Direct Measurement of Normal Surface Forces Due to
Double-layer Repulsion 185
Theoretical Studies 188
Structure of Liquids near Surfaces 19 0
4 Studies on Disperse Systems 191
Monodisperse Systems 191
Silver Iodide 198
Clays 199
Secondary Minimum Phenomena 201
Kinetics of Coagulation 202
Review Articles 206
5 Steric Stabilization 207
6 Electrokinetic Studies 21 1
...
Vlll Contents
Chapter 6 Emulsions
By 8. Vincent
1 Introduction 220
2 Emulsification with Surfactants; Microemulsions 221
3 Emulsification with Polymers 225
4 Kinetic Studies of Emulsion Stability 226
5 Droplet Coalescence 229
6 Ultracentrifuge Studies 232
7 Interfacial Structure and Stability 23 3
8 Rheological Properties 235
9 Electrical Properties 237
Chapter 7 Non-aqueous Systems
By 5. Vhcenf
1 Introduction 238
2 Dispersion Stability: Theoretical Aspects 239
3 Dispersion Stability :E xperimental 242
4 ChargeEffects 252
5 Association Colloids 253
Author I ndex 257