Surface Characterization of Advanced Polymers Edited by Luigia Sabbatini and Pier Giorgio Zambonin VCH Weinheim New York Basel Cambridge Tokyo
1 Spectroscopies for Surface Characterization 1 E. Desimoni and P. G. Zambonin 1.1 Introduction 1 1.2 Surface Specificity and Vacuum Requirements 5 1.3 X-Ray Photoelectron Spectroscopy 6 1.3.1 Principles 6 1.3.2 Escape Depth 9 1.3.3 Instrumentation 10 1.3.4 Sputtering and Depth-Profiles 12 1.3.5 Spectral Features 13 1.3.6 Data Acquisition and Analysis 16 1.3.7 Quantification 19 1.4 High Resolution Electron Energy Loss Spectroscopy 20 1.4.1 Electron Energy Loss Spectroscopy 20 1.4.2 Electron Scattering Mechanisms 21 1.4.3 Instrumentation 22 1.4.4 Data Analysis and Interpretation, Some Practical Examples.... 23 1.5 Ion Scattering Spectroscopy 28 1.5.1 Physical Principles and Quantification 28 1.5.2 Instrumentation 30 1.5.3 Applicative Examples 31 1.6 Static Secondary Ion Mass Spectrometry 33 1.6.1 Secondary Ion Mass Spectrometry 33 1.6.2 Physical Principles and Quantification 35 1.6.3 Instrumentation 37 1.6.4 Applicative Examples 39 1.7 References 43
VIII 2 Electron Induced Vibrational Spectroscopy (HREELS) 47 /./. Pireaux 2.1 Introduction 47 2.2 The Experimental Set-Up 48 2.3 Polymerie Materials and High-Resolution Electron Energy Loss Spectroscopy (HREELS) 51 2.4 Theoretical Issues 58 2.4.1 Three Interaction Mechanisms 58 2.4.2 Very Low Electron Mean Free Path in Polymers 61 2.5 Applications 62 2.5.1 A New Spectroscopy Versus X-Ray Photoelectron Spectroscopy and (Time-of-Flight) Secondary Ion Mass Spectrometry [(TOF)SIMS]. 62 2.5.2 Resonance/Impact Effects 63 2.5.3 Surface Sensitivity 65 2.5.4 Polymer Chain Structure 68 2.5.5 Surface Diffusion 72 2.5.6 Conducting Polymers 73 2.5.7 Metallized Polymers 75 2.6 Developments 77 2.6.1 Instrumental Aspects 77 2.6.2 Theoretical Aspects; Computational Help 78 2.7 Conclusions 79 t 2.8 Acknowledgements 80 2.9 References 80 3 The Application of Static Secondary Ion Mass Spectrometry (SIMS) to the Surface Analysis of Polymer Materials 83 N. M. Reed and J. C. Vickerman 3.1 Introduction 83 3.2 Acquisition of Static Secondary Ion Mass Spectra (SIMS) from Organic Materials 88 3.2.1 Sample Charging 88 3.2.2 What are Static Conditions for Organic Materials? 90 3.2.2.1 Static Conditions - Ions Versus Atoms 90 3.2.2.2 Static Conditions - Quadrupole Versus ToF SIMS 94 3.3 Mechanism of Secondary Ion Generation 95 3.3.1 Nascent Ion Molecule Model 96 3.3.2 Desorption Ionization 96 3.3.3 Experimental Observations 98 3.3.3.1 Preformed Ions 98
IX 3.3.3.2 Stabilized Ion Pairs 100 3.3.4 Mass Spectrometer/Mass Spectrometer (MS/MS) Studies of the Ion Generation Process 100 3.4 Spectral Interpretation 111 3.4.1 Sub-Monomer Region 112 3.4.2 «-Merlons ' 113 3.4.3 Oligomer Ions 113 3.4.4 Listing of Polymers Investigated to Date by SSIMS 113 3.5 Quantification 115 3.5.1 Surface Composition of Methacrylate Copolymers 116 3.5.2 Polyether - Polyester Copolymers 120 3.5.3 Ion Beam Effects and Quantification 120 3.5.4 Quantification - Polystyrene/Polyhydroxystyrene - Matrix Effect Problems 120 3.5.5 Low Mass Ion Ratios - a Measure of Elemental Compositions... 122 3.5.6 Direct Intensity Measurements - Special Situations 122 3.5.7 Conclusions 122 3.6 Static SIMS Studies of Copolymers of Biological Importance... 123 3.6.1 Methacrylate Copolymers Employed in Drug Delivery 123 3.6.2 Surface Chemical Structure of Poly(orthoesters) 127 3.7 Static SIMS Studies of Polymer Colloid Surfaces 132 t 3.8 Plasma Treated Surfaces 135 3.8.1 Plasma Treated Polypropylene Surfaces 135 3.8.2 Degree of Aromaticity 138 3.8.3 Polymer/Ammonia Plasma Interactions 138 3.8.4 Chain Scission 139 3.9 Surface Interactions Related to Cluster Ion Formation 144 3.9.1 Generation of SSIMS Clusters from Polycarbonates 144 3.9.2 ToF SIMS Applied to Polymer Molecular Weight Determination.. 149 3.9.3 Chemical Surface Modification 151 3.9.4 Characterization of Surface Interactions 153 3.10 Technological Applications of Static SIMS 154 3.10.1 Characterization of the Preparation of Optical Discs 155 3.10.2 Investigation of Contact Lens Properties 155 3.10.3 Biosensors 157 3.10.4 Drug Delivery Systems 158 3.11 References 160
X 4 Low Energy Ion Scattering Spectrometry of Polymer Surface Composition and Structure 163 T.G. Vargo, J.A. Gardella, Jr., R.L. Schmitt, K.J. Hook, T.J. Hook, L. Salvati, Jr. 4.1 Introduction 163 4.1.1 Ion Beam Methods 163 4.1.1.1 Distinctions, Fundamentals 163 4.1.1.2 Ion Beam Interactions for Analysis -SIMS, RBS, LEISS.... 164 4.1.1.3 Fundamentas of LEISS 165 4.1.2 Utility of Low Energy Ion Scattering 165 4.1.2.1 Surface Sensitivity 165 4.1.2.2 Shielding and Shadowing 166' 4.1.2.3 Impact Collision Ion Scattering Spectrometry 167 4.1.3 LEISS of Polymer Surfaces 167 4.1.3.1 Sample Handling 167 4.1.3.2 Damage and Static Conditions 168 4.2 Instrumentation/Experimental 167 4.3 LEISS Studies of Polymerie Systems 170 4.3.1 Overview 170 4.3.2 Studies of Homopolymer Surface Structure 170 4.3.3 Multiple Technique Depth Profiles of Multicomponent Polymers 173 4.4 Background and Inelastic Effects 174 4.4.1 Contributing Physical Processes - Current Literature 174 4.4.2 Experimental Investigations of Background and Sputtering in Crystalline Polymers 174 4.5 Current Trends and Future Expectations 178 4.5.1 ICISS with Alkali Metal Ions 178 4.5.2 TOF-DRS 179 4.6 References 179 5 X-Ray Photoelectron Spectroscopy Analysis of Conducting Polymers 181 C. Malitesta, G. Morea, L. Sabbatini, P. G. Zambonin 5.1 Introduction 181 5.2 Polypyrroles 183 5.2.1 History, Preparation, and Properties 183 5.2.2 X-Ray Photoelectron Spectroscopy Studies 185 5.3 Polythiophenes 193 5.3.1 History, Preparation, and Properties 193 5.3.2 X-Ray Photoelectron Spectroscopy Studies 195 5.4 Polyanilines 201
XI 5.4.1 History, Preparation, and Properties 201 5.4.2 X-Ray Photoelectron Spectroscopy Studies 206 5.5 Miscellanea 214 5.6 Conclusions 215 5.7 References 216 6 Chemical Derivatization Methods for Enhancing the Analytical Capabilities of X-Ray Photoelectron Spectroscopy and Static Secondary Ion Mass Spectrometry 221 A. Chilkoti and B. D. Ratner 6.1 Preface 221 6.2 Chemical Derivatization X-Ray Photoelectron Spectroscopy (XPS). 221 6.2.1 Introduction 221 6.2.2 Derivatization XPS Literature Review 224 6.2.3 Derivatization XPS Case Studies 228 6.2.3.1 Hydroxyl Derivatization Reactions 228 6.2.3.2 Hydrazine Derivatization Reaction 242 6.2.3.3 Trifluorethanol/Di-Tertbutylcarbodiimide Derivatization Reaction.. 245 6.3 Chemical Derivatization Static Secondary Ion Mass Spectrometry (SIMS) 247 6.3.1 Introduction 247 6.3.2 Derivatization Static SIMS Literature Review 248 6.3.3 Derivatization Static SIMS Case Studies 248 6.3.3.1 Analysis of Oxygen-Containing Plasma Deposited Films 248 6.3.3.2 Derivatization of Conventional Polymers 251 6.4 Conclusions 253 6.5 Acknowledgements 254 6.6 References 254 7 Data Analysis in X-Ray Photoelectron Spectroscopy 257 P.M.A. Sherwood 7.1 Introduction 257 7.2 Data-Collection Systems 257 7.3 Software for Data Analysis 258 7.4 Databases 259 7.5 Simple Data Operations 259 7.6 Satellite Removal 260 7.7 Data Considerations 260 7.8 The Fitting of Data 262
XII 7.9 Smoothing 264 7.9.1 Curve Fitting - the Use of Splines 265 7.9.2 Convolutional Algorithms 265 7.9.3 Fourier Transform - Frequency Filtering 268 7.10 The Analysis of Overlapping Spectral Features 269 7.10.1 Derivative Spectra 269 7.10.2 Deconvolution Methods 271 7.10.3 Factor Analysis Method 279 7.10.4 Pattern Recognition Method 281 7.10.5 Spectral Ratioing Method 281 7.10.6 The Use of the Kaiman Filter 281 7.10.7 Difference Spectra 281 7.10.8 Addition Spectra 283 7.10.9 Curve Synthesis and Curve Fitting 283 7.10.9.1 Fitting Functions 283 7.10.9.2 Least-Squares Curve Fitting 285 7.10.10 Fitting Theoretical Calculations to Valence Band Spectra 286 7.11 Background Removal 290 7.11.1 Linear Backgrounds 291 7.11.2 Integral (Nonlinear) Backgrounds 291 7.11.3 Backgrounds Based upon Elastic and Inelastic Loss Processes... 291 7.12 Acknowledgements 293 7.13 References 293 Index 299