Table Of ContentSurface and Interfacial
Aspects of Biomedical Polymers
Volume 1
Surface Chemistry and Physics
Surface and Interfacial
Aspects of Biomedical Polymers
Volume 1
Surface Chemistry and Physics
Edited by
Joseph D. Andrade
University of Utah
Salt Lake City, Utah
PLENUM PRESS • NEW YORK AND LONDON
Library of Congress Cataloging in Publication Data
Main entry under title:
Surface and interfacial aspects of biomedical polymers.
Bibliography: v. 1. p.
Includes index.
Contents: v. 1. Surface chemistry and physics-1. Biomolecules. 2. Polymers and poly
merization. 3. Surface chemistry. I. Andrade, Joseph D., 1941-
OD419.S94 1985 574.19/24 84-26601
(v. 1)
ISBN 978-1-4684-8612-4 ISBN 978-1-4684-8610-0 (eBook)
DOl 10.1007/978-1-4684-8610-0
© 1985 Plenum Press, New York
Softcover reprint of the hardcover 1s t edition 1985
A Division of Plenum Publishing Corporation
233 Spring Street, New York, N.Y. 10013
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
J. D. Andrade • College of Engineering, University of Utah, Salt Lake
City, Utah 84112
F. M. Fowkes • Department of Chemistry, Lehigh University,
Bethlehem, Pennsylvania 18015
D. E. Gregonis • D~partment of Materials Science and Engineering,
College of Engineering, University of Utah, Salt Lake City, Utah 84112
B. Hupfer • Institut fur Organische Chemie, Johannes Gutenberg
Universitat, Johann-Joachim-Bercher-Weg 18-20, D-6500 Mainz, FRG
M. S. Jhon • Korean Advanced Institute of Science, P.O. Box 150,
Chongyangni, Seoul, Korea
K. Knutson • Department of Pharmaceutics, College of Pharmacy, Uni
versity of Utah, Salt Lake City, Utah 84112
J. Lyklema • Laboratory for Physical and Colloid Chemistry, Agricul
tural University, De Dreijen 6/6703 BC Wageningen, The Netherlands
D. J. Lyman • Department of Materials Science and Engineeering, Uni
versity of Utah, Salt Lake City, Utah. 84112
Y. G. Oh • Korean Advanced Institute of Science, P.O. Box 150,
Chongyangni, Seoul, Korea
B. D. Ratner • Department of Chemical Engineering, University of
Washington, Seattle, Washington 98195
M. Reichert • Department of Bioengineering, College of Engineering,
University of Utah, Salt Lake City, Utah 84112
H. Ringsdorf • Institut fur Organische Chemie, Johannes Gutenberg
Universitat, Johann-Joachim-Bercher-Weg 18-20, D-6500 Mainz, FRG
L. M. Smith • Department of Bioengineering, College of Engineering,
University of Utah, Salt Lake City, Utah 84112
v
Preface
This book is intended to provide a fundamental basis for the study of the
interaction of polymers with living systems, biochemicals, and with aqueous
solutions.
The surface chemistry and physics of polymeric materials is a subject
not normally covered to any significant extent in classical surface chemistry
textbooks. Many of the assumptions of classical surface chemistry are invalid
when applied to polymer surfaces. Surface properties of polymers are
important in the development of medical devices and diagnostic products.
Surface properties are also of vital importance in fields such as adhesion,
paints and coatings, polymer-filler interactions, heterogeneous catalysis,
composites, and polymers for energy generation.
The book begins with a chapter considering the current sources of
information on polymer surface chemistry and physics. It moves on to
consider the question of the dynamics of polymer surfaces and the implica
tions of polymer surface dynamics on all subsequent characterization and
interfacial studies. Two chapters are directed toward the question of model
polymers for preparing model surfaces and interfaces. Complete treatments
of X-ray photoelectron spectroscopy and attenuated total reflection infrared
spectroscopy are given. There is a detailed treatment of the contact angle
with particular emphasis on contact angle hysteresis in aqueous systems,
followed by chapters on interfacial electrochemistry and interface acid-base
charge-transfer properties. The very difficult problem of block and graft
copolymer surfaces is also discussed. The problem of theoretical calculations
of surface and interfacial tensions is presented. Raman spectroscopy is
considered as an analytical technique for polymer surface characterization.
The final chapter treats a number of techniques which have not been treated
in previous chapters as well as some conclusions and expectations.
It is hoped that the book will serve as a useful text in the general area
of polymer surface analysis and characterization and make its way into
advanced undergraduate and graduate courses in surface chemistry and
physics as well as serve as a reference source for researchers and engineers
in the general area of polymer surfaces and interfaces. The treatment is by
no means complete. Understanding of the properties of polymer surfaces
vii
viii PREFACE
is minimal at the present time, and considerable advances in theory and
experimental techniques are required before we can expect to have a
thorough understanding of the surface properties of organic systems. Let
us hope that this book will help those who decide to enter this stimulating
field.
When I began the study of polymer surfaces as biomaterials some fifteen
years ago, I lacked any formal training in the general area of surface
chemistry. Thus, I am particularly indebted to a number of classic textbooks
which are highly suitable for self-study, many of which are listed in Chapter
One. The texts by Bikerman; Davies and Rideal; Aveyard and Haydon;
Kipling; Kaelble; DeBoer; Adam; and Adamson have been particularly
helpful. lowe an enormous debt to my students and coworkers over the
years as we attempted to learn and understand the basic principles of
polymer surfaces. Although it was often the blind leading the blind, with
many hesitations and frustrations, the exercise was always challenging,
stimulating and generally productive. I am also in debt to a number of
stimulating and even controversial colleagues in the area of surfa<;e
chemistry of polymers who have provided hypotheses, conclusions, and
discussions: R. E. Baier, A. W. Neumann, F. M. Fowkes, B. D. Ratner,
A. S. Hoffman, F. Holly, L. Vroman, O. Wichterle, D. Lim, P. M. Sawyer,
D. J. Lyman, S. W. Kim, and others.
I wish to thank and to dedicate this volume to W. J. Kolff, pioneer in
artificial organs and supporter, promoter, and encourager of often inex
perienced people with new and interesting ideas.
J. D. Andrade, Salt Lake City, December 1983
"All we can create and cry is interface.
It forms and folds to mate and die and
by its grace
Life's clutch can hold a cloudy sky
, till water laps the coast.
That is perhaps why what we touch
is uppermost"
Leo Vroman
Contents
1. Introduction to Surface Chemistry and Physics of Polymers
J. D. Andrade
I. Sources 1
2. Objectives 5
3. Overview 9
4. Limitations 12
5. References 13
2. Polymer Surface Dynamics
J. D. Andrade, D. E. Gregonis, and L. M. Smith 15
1. Introduction . . . . . . . . . . . . . 15
2. Polymer Transitions and Relaxations 18
3. Probing Polymer Motions and Transitions 21
3.1. Bulk Methods ........ . 21
3.2. Inverse Gas Chromatography (JGC) 27
4. Polymer Surface Motions 31
4.1. Inverse GC . . . . . . 31
4.2. Filled Systems .... 34
4.3. Contact Angle Methods 34
4.4. Other Methods 37
5. Conclusions 38
6. Summary 39
Acknowledgments 39
References 39
3. Model Polymers for Probing Surface and Interfacial
Phenomena
D. E. Gregonis and J. D. Andrade
l. Introduction . . . . . . . . . 43
2. Stereoregular Polymers .... 44
2.1. Purpose ( Stereochemistry) 44
ix
x CONTENTS
2.2. Chemistry ...... 45
2.3. Bulk Properties . . . . 46
2.4. Surface Characterization 47
3. Hydroxyethyl Methacrylate Copolymers 47
3.1. Purpose (Systemic Hydration) 47
3.2. Chemistry ..... 48
3.3. Bulk Properties 49
3.4. Surface Characteristics 49
4. Block Copolymers .... 51
4.1. Purpose (Morphology) 51
4.2. Styrene-Hydroxylated Butadiene-Styrene Triblocks 52
4.3. HEMA-Styrene-HEMA Triblocks . 55
5. Alkyl Methacrylates ......... 56
5.1. Purpose (Systematic Change in T,,) 56
5.2. Chemistry ..... 56
5.3. Bulk Characteristics 57
5.4. Surface Characteristics 57
6. Derivatized Agarose 58
6.1. Purpose (Modification for Systemic Hydrophobicity) 58
6.2. Chemistry ..... 60
6.3. Bulk Characteristics 61
6.4. Surface Characteristics 63
7. Polyurethanes ...... 66
7.1. Purpose (Practical Biomedical Elastomers) 66
7.2. Chemistry ..... 66
7.3. Bulk Properties 68
7.4. Surface Characteristics 69
8. Poly(a-Amino Acids) . . . 69
8.1. Purpose (Naturally Occurring Repeat Units) 69
8.2. Chemistry 69
8.3. Surface Analysis 71
9. Summary/Conclusions 71
Acknowledgments 72
References ...... 72
4. Polymeric Oriented Monolayers and Multilayers as Model
Surfaces
B. Hupfer and H. Ringsdorf
I. Introduction . . . . . . 77
1.1. Biological Membranes 77
1.2. Models for Biomembranes 79
CONTENTS xi
1.3. Characterization of Mono- and Multilayers . . . . 81
1.4. Stability of Conventional Model Membrane Systems 82
2. Polymerized Model Membranes 82
2.1. Polymerizable Lipids ....... . 82
2.2. Polymerized Monolayers . . . . . . . 86
2.2.1. Monolayers with One Component 86
2.2.2. Mixed Monolayers 91
2.3. Polymeric Multilayers ..... 95
2.4. Polymeric Black Lipid Membranes 95
2.5. Polymeric Vesicles (Liposomes) 97
3. Conclusions 99
References 99
5. X-ray Photoelectron Spectroscopy (XPS)
J. D. Andrade
1. Introduction . . . . . . . . 105
2. Basic Principles of XPS . . . 107
2.1. The Photoelectric Effect 107
2.2. Basic Experiment 109
2.3. Instrument . . . . 111
2.3.1. X-ray Source 114
2.3.2. Sample 117
2.3.3. Analyzer/Detector 117
2.3.4. Instrument Sources 118
2.4. Charging and Energy Referencing 119
2.5. Spectra and Spectral Features . . 122
3. Elemental Analysis . . . . . . . . . 125
3.1. Qualitative and Semiquantitative Analysis 125
3.2. Quantitative Elemental Analyses 138
3.2.1. Basics . . . . . . . . . . . . 138
3.2.2. X-ray Flux, 10 ........ 139
3.2.3. Differential Photoionization Cross Section, Ui,k 140
3.2.4. Instrument Transmission or Throughput Function,
T;.k .......... 140
3.2.5. Mean Free Path, Ai,k .•.. 141
3.2.6. Measured Intensities, Ni,k 141
3,2.7. Quantitative Analysis Summary 143
4. Chemical Bonding 143
4.1. Chemical Shifts . . . 143
4.2. Energy Referencing 150
4,3. Initial and Final States 151
xii CONTENTS
4.4. Auger Processes 152
4.5. Shake-up Satellites 156
4.6. Multiplet Splitting 159
4.7. Molecular Orbitals 159
4.8. Summary 161
5. Functional Group Labelling 163
6. Data Processing 169
6.1. Curve Resolution 169
6.2. Smoothing 171
6.3. Derivatives 172
6.4. Deconvolution 173
6.5. Summary 174
7. Variable Angle Methods 175
7.1. Introduction 175
7.2. Mean Free Paths 176
7.3. Uniform Overlayers 184
7.4. Patchy Overlayers 186
7.5. Surface Concentration Gradients 186
7.6. Limitations 190
Acknowledgments 190
References 191
6. Surface Infrared Spectroscopy
K. Knutson and D. J. Lyman
I. Introduction . . . . . . . 197
2. Infrared Spectroscopy 198
3. Principles of Internal Reflection 203
3.1. Electromagnetic Radiation Described as Waves 204
3.1.1. Vectorial Properties of Electromagnetic Waves 204
3.1.2. Energy Flux of Electromagnetic Radiation 206
3.2. Reflection and Refraction of Electromagnetic Waves at an
Interface . . . . . . . . . . . . . . . . . . . .. 207
3.3. Total Internal Reflection . . . . . . . . . . . . .. 209
3.3.1. Presence of an Electromagnetic Field in the Second
Medium . . . . . . . . . . . . . . . . .. 210
3.3.2. Sampling the Electromagnetic Field in the Second
Medium . . . . . . . . . . . . . .. 213
3.3.3. Sampling Depth of Electromagnetic Field in the
Second Medium .............. 214
3.3.4. Sampling Depth as a Function of Experimental
Variables ................. 218
