Dynamic Light Scattering: Applications of Photon Correlation Spectroscopy

429 Pages·1985·8.506 MB·English

by  R. Pecora (auth.), Robert Pecora (eds.)

Dynamic Light
Scattering
Applications of
Photon Correlation Spectroscopy
Dynamic Light
Scattering
Applications of
Photon Correlation Spectroscopy
Edited by
Robert Pecora
Stanford University
Stanford, Cafijornia
Plenum Press • New Yo rk and London
Library of Congress Cataloging in Publication Data
Main entry under tide:
Dynamic light scattering.
Includes bibliographies and index.
1. Light beating spectroscopy. 2. Light-Scattering. I. Pecora, Robert, 1938-
QC454.L63D96 1985 535.8'4 84-24831
ISBN-13: 978-1-4612-9459-7 e-ISBN-13: 978-1-4613-2389-1
DO!: 10.1007/978-1-4613-2389-1
© 1985 Plenum Press, New York
A Division of Plenum Publishing Corporation
233 Spring Street, New York, N.Y. 10013
Softcover reprint of the hardcover 1s t edition 1985
All rights reserved
No part of this book may be reproduced, stored in a retrieval system, or transmitted
in any form or by any means, electronic, mechanical, photocopying, microfilming,
recording, or otherwise, without written permission from the Publisher
Contributors
Victor A. Bloomfield
Department of Biochemistry, University of Minnesota, St. Paul, Minnesota
B.Chu
Department of Chemistry, State Un iversity of N ew York, Stony Brook, N ew Y ork
N. C. Ford, Jr.
Langley-Ford Instruments, Amherst, Massachusetts
c. C. Han
National Bureau ofStandards, Washington D.C.
Norman A. Mazer
Department of Physics, Massachusetts Institute of Technology, Cambridge,
Massachusetts; and Department of Medicine, Brigham and Women's Hospital,
Boston, Massachusetts
G. D. Patterson
Department oJ Chemistry, Carnegie-M eI/on University, Pittsburgh, Pennsylvania
R. Pecora
Department oJChemistry, StanJord University, StanJord, California
P. N. Pusey
Royal Signals and Radar Establishment, Malvern, Worcestershire, England
D. W. Schaefer
Sandia National Laboratories, Albuquerque, New Mexico
Toyoichi Tanaka
Department oJ Physics and Center Jor Materials Science and Engineering,
Massachusetts Institute ofTechnology, Cambridge, Massachusetts
R. J. A. Tough
Royal Signals and Radar Establishment, Malvern, Worcestershire, England
Kar! Zero
Department oJ Chemistry, Stariford Un iversity, Stariford, California
v
Preface
In the twenty years since their inception, modern dynamic light-scattering
techniques have become increasingly sophisticated, and their applications
have grown exceedingly diverse. Applications of the techniques to problems
in physics, chemistry, biology, medicine, and fluid mechanics have prolifer
ated. It is probably no longer possible for one or two authors to write a
monograph to cover in depth the advances in scattering techniques and the
main areas in which they have made a major impact. This volume, which
we expect to be the first of aseries, presents reviews of selected specialized
areas by renowned experts. It makes no attempt to be comprehensive; it
emphasizes a body of related applications to polymeric, biological, and
colloidal systems, and to critical phenomena.
The well-known monographs on dynamic light scattering by Berne and
Pecora and by Chu were published almost ten years ago. They provided
comprehensive treatments of the general principles of dynamic light scat
tering and gave introductions to a wide variety of applications, but natu
rally they could not treat the new applications and advances in older ones
that have arisen in the last decade. The new applications include studies of
interacting particles in solution (Chapter 4); scaling approaches to the
dynamics of polymers, including polymers in semidilute solution (Chapter
5); the use of both Fabry-Perot interferometry and photon correlation
spectroscopy to study bulk polymers (Chapter 6); studies of micelIes and
microemulsions (Chapter 8); studies of polymer gels (Chapter 9). In addi
tion, the considerable advances made in the study of critical phenomena are
reviewed (Chapter 7), as weil as progress in the application of the depolar
ized dynamic scattering technique to a wide variety of systems. A survey of
the uses of the light-scattering and laser Doppler veiocimetry to study
systems of biological interest is given in the final chapter (Chapter 10).
The current volume contains much introductory material for the begin
ner in light scattering. Chapter 2, for instance, should be especially useful
for such readers and should be of aid to anyone contemplating setting up a
dynamic light-scattering laboratory. The serious novice is, however, urged
vii
viii Preface
to consult the two monographs mentioned above for background informa
tion about time correlation functions, the electromagnetic theory of scat
tering, the elementary theory of Brownian motion, hydrodynamics,
generalized hydrodynamics, molecular reorientation in liquids, dynamics of
a single polymer chain, and nonequilibrium thermodynamics, as weB as
other topics in their relation to dynamic light scattering.
It is a pleasure to express my thanks to the authors, who have taken so
much time from their busy schedules to contribute to this volume.
Stanford, California Robert Pe co ra
Contents
Chapter I
Introduction .......................................................................... .
R. Pecora
References ............................................................... 6
Chapter 2
Light Scattering Apparatus .......... ... ........ ................................... 7
N. C. Ford, Jr.
2.1. Introduction ...... ........... ........ ..... .............................. 7
2.2. Electromagnetic W a ves . . . . . . . . . . . . . .. . . .. . . . . . . .. . .. . . . . .. . . . .. . . . . . . 8
2.3. Light Scattering ........................................................ 11
2.3.1. Background................................................... 11
2.3.2. Fluctuations................................................... 12
2.3.3. The Coherence Area ......................................... 15
2.3.4. Time Dependence ............................................ 16
2.3.5. Local Oscillator...... ................. ........................ 19
2.4. The Light Scattering Experiment................................... 19
2.4.1. Introduction .................................................. 19
2.4.2. The Light Source............................................. 20
2.4.3. The Spectrometer........... .. ..................... ........... 26
2.4.4. The Detector. . . . . . .. . . . .. . . . . . . .. .. . . . . . . . . . . . . . . . . . . . . .. . . .. . . 29
2.4.5. Signal Analyzers .............................................. 35
2.5. Signal-to-Noise Ratio................................................. 40
2.5.1. Introduction .................................................. 40
2.5.2. Effects due to Finite Intensity ............................. 40
2.5.3. Effects due to Finite Experiment Duration............. 42
2.5.4. Effects due to Unwanted Scattered Light............... 43
2.6. Data Analysis.. ....... ......... ... .... .. ..... .. .......... .. ..... ...... .. 46
2.6.1. Introduction ........................ .................. ........ 46
2.6.2. Selecting the Theoretical Form............................ 46
2.6.3. U se of the X2 Test.... ............ ............................. 48
ix
x Contents
2.6.4. Summary of Possible Forms............................... 49
2.6.5. Polydispersity................................................. 50
2.7. SpeciaIApparatus...................................................... 51
2.7.1. Electrophoretic Light Scattering.. ..... .......... ......... 51
2.7.2. Fabry-Perot Interferometers .. ....... ............. ........ 53
2.7.3. SoftwareCorrelators......................................... 56
2.7.4 Cross-Correlation Experiment ........ ..... ...... ..... ..... 56
2.8. Conc1usions............................................................. 57
References and Notes................................................. 57
Chapter 3
Dynamic Depolarized Ligbt Scattering ................. . . . . . . . . . . . . . . . . . . . . . . . . 59
Karl Zero and R. Pecora
3.1. Introduction ....... ....... ....... ..... .... ... ...... ..... .... ...... ...... 59
3.2. Principles of Depolarized Scattering. ... ... .. ........... . ..... ... .. 60
3.2.1. Scattering Configurations .................................. 60
3.2.2. Physical Principles ........................................... 61
3.3. Rigid Macromolecules in Dilute Solution........ ........ ... ..... 65
3.3.1. Hydrodynamics of Rigid Macromolecules.............. 65
3.3.2. Interferometric Studies ...................................... 68
3.3.3. Photon Correlation Studies .. ...... ... .. ...... ........... .. 69
3.4. Rod-Shaped Macromolecules in Semidilute Solutions ........ 72
3.5. Flexible Macromolecules............. .... ....... ......... ...... ...... 75
3.6. Rotation of Small Moleeules in Viscous Media................. 79
3.7. Resonance-Enhanced Depolarized Dynamic Light
Scattering .................. ..... ... .... .. ......... .. ..... ...... ..... ..... 80
References and Notes.... . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 81
Chapter 4
Particle Interactions ........ ....... ..... ....... ...... ..... . ... .. ..... . .......... .. ... 85
P. N. Pusey and R. J. A. Tough
4.1. Introduction ........... ............ ........................ ..... ........ 85
4.2. Quantities Measured by Light Scattering ..... ....... .. ..... .. ... 90
4.2.1. Introduction ....... ...... ... ........ ...... ....... ............. 90
4.2.2. Monodisperse Systems ........ ... ........ ........... ... ..... 91
4.2.3. Polydisperse Systems.......................... .......... .... 92
4.2.4. Discussion..................................................... 94
4.3. Theory ................................................................... 96
4.3.1. Introduction .................................................. 96
4.3.2. Stokes-Einstein Relations.................................. 97
4.3.3. The Generalized Smoluchowski Equation.............. 101
Contents xi
4.3.4. Hydrodynamic Interactions ................................ 103
4.3.5. Short-Time Motions..... .... ..... ...... ....... ......... ..... 108
4.3.6. Projection Operator Analysis.............................. 114
4.3.7. Dynamics in the Small-q Limit-Cooperative and
Self-Diffusion ................................................ 120
4.4. Charged Particles in Dilute Suspension (Negligible
Hydrodynamic Interactions) ...................................... 126
4.4.1. Introduction .................................................. 126
4.4.2. Single-Particle Motions (q > qm' all r) .................. 130
4.4.3. The First Cumulant (rB ~ r ~ ru all q) .............. ... 136
4.4.4. Low-q Limit and the Effect of Polydispersity.......... 137
4.4.5. Memory Effects ...... ......... .... ............... .......... ... 142
4.5. Effects ofHydrodynamic Interactions............................. 144
4.5.1. Introduction .................................................. 144
4.5.2. Theory of the Collective Diffusion Coefficient in the
Hydrodynamic Regime ............ ..... .................... 145
4.5.3. Experimental Results ........................................ 149
4.5.4. Microemulsions .............................................. 154
4.5.5. Hydrodynamic Effects at Finite q......................... 158
4.6. Small-Ion Effects ...................................................... 159
4.7. Conclusions ..................... ........................................ 162
4.8. Addendum .......... ............ .... .................... ....... ......... 164
References and Notes. ................................................. 171
Chapter 5
Quasielastic Light Scattering from Dilute and Semidilute Polymer
Solution. . . .. . . . . . .. . . .. . . . . . . . . . . . .. . . . .. . . . . . . . . . . . . . . . .. . . . . . . . .. . . . . . . . . . . . . . .. . . . . . . 181
D. W. Schaefer and C. C. Han
5.1. In trod uction . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. . .. . . . . . .. . . .. . . . . . . . . . . . . . . . . . 181
5.2. The Single Chain....................................................... 182
5.2.1. Basic Polymer Statistics..................................... 182
5.2.2. Dynamical Regimes.......................................... 186
5.2.3. Center-of-Mass Diffusion (qR ~ 1)....................... 193
5.2.4. Internal Dynamics and the Dynamic Structure
Factor .......................................................... 200
5.3. Vi rial Regime............................................................ 214
5.4. Semidilute Solutions................................................... 217
5.4.1. Introduction .................................................. 217
5.4.2. Dynamical Regimes. ........ ...... ....... ............... ..... 221
5.4.3. Conclusions ................................................... 240
References ............................................................... 241