Polymer Microscopy Second edition LINDA C. SAWYER Hoechst Celanese Corporation Summit, NJ USA and DAVID T. GRUBB Cornell University Ithaca, NY USA CHAPMAN & HALL London Glasgow Weinheim New York Tokyo Melbourne Madras
Color plates appear between pages 274 and 275 Preface to the second edition Acknowledgements xi xiii 1 Introduction to polymer morphology 1 1.1 Polymer materials 1 1.1.1 Introduction 1 1.1.2 Definitions 2 1.2 Polymer morphology 3 1.2.1 Amorphous polymers 4 1.2.2 Semicrystalline polymers 4 1.2.3 Liquid crystalline polymers 7 1.3 Polymer processes 7 1.3.1 Extrusion of fibers and films 8 1.3.2 Extrusion and molding 10 1.4 Polymer characterization 12 1.4.1 General techniques 12 1.4.2 Microscopy techniques 12 1.4.3 Specimen preparation methods 13 1.4.4 Applications of microscopy to polymers 14 1.4.5 New microscopy techniques 14 2 Fundamentals of microscopy 17 2.1 Introduction 17 2.1.1 Lens-imaging microscopes 18 2.1.2 Scanning-imaging microscopes 20 2.2 Optical microscopy (OM) 21 2.2.1 Introduction,. 21 2.2.2 Objective lenses :;. *> 21 2.2.3 Imaging modes, 22
vi Contents 2.2.4 Measurement of refractive index 23 2.2.5 Polarized light 24 2.3 Scanning electron microscopy (SEM) 25 2.3.1 Introduction 25 2.3.2 Imaging signals 28 2.3.3 SEM optimization 29 2.3.4 Special SEM types 30 2.4 Transmission electron microscopy (TEM) 30 2.4.1 Imaging in the TEM 30 2.4.2 Diffraction techniques 32 2.4.3 Phase contrast and lattice imaging 33 2.5 Scanning probe microscopy (SPM) 33 2.6 Microscopy of radiation sensitive materials 36 2.6.1 SEM operation 36 2.6.2 Low dose TEM operation 37 2.7 Analytical microscopy 39 2.7.1 X-ray microanalysis 39 2.7.2 X-ray analysis in the SEM vs. AEM 40 2.7.3 Elemental mapping. 41 2.8 Quantitative microscopy 41 2.8.1 Stereology and image analysis 41 2.8.2 Calibration 42 2.8.3 Image processing 42 2.9 Dynamic microscopy 43 2.9.1 Stages for dynamic microscopy 43 3 Imaging theory 48 3.1 Imaging with lenses., 48 3.1.1 Basic optics 48 3.1.2 Resolution 50 3.1.3 Electron diffraction 54 3.1.4 Contrast mechanisms 56 3.1.5 Illumination systems 58 3.2 Imaging by scanning electron beam 60 3.2.1 Scanning optics 60 3.2.2 Beam - specimen interactions 61 3.2.3 Image formation 63 3.3 Imaging by scanning a solid probe 64 3.4 Polarizing microscopy 65 3.4.1 Polarized light 65 3.4.2 Anisotropic materials 65 3.4.3 Polarizing microscopy 68 3.5 Radiation effects 70 3.5.1 Effect of radiation on polymers 70 3.5.2 Radiation doses and specimen heating 73 3.5.3 Effects of radiation damage on the image 74
vii 3.5.4 Noise limited resolution 77 3.5.5 Image processing 78 4 Specimen preparation methods 83 4.1 Simple preparation methods 83 4.1.1 Optical preparations 83 4.1.2 SEM preparations 84 4.1.3 TEM preparations 84 4.1.4 SPM preparations 89 4.2 Polishing 91 4.2.1 Polishing artifacts. 91 4.2.2 Polishing specimen surfaces 91 4.3 Microtomy 94 4.3.1 Peelback of fibers/films for SEM 94 4.3.2 Sections for OM 95 4.3.3 Sections for SEM 98 4.3.4 Ultrathin sectioning 99 4.3.5 Ultrathin cryosectioning 100 4.4 Staining * 102 4.4.1 Introduction 102 4.4.2 Osmium tetroxide 103 4.4.3 Ebonite 108 4.4.4 Chlorosulfonic acid 110 4.4.5 Phosphotungstic acid 111 4.4.6 Ruthenium tetroxide 112 4.4.7 Silver sulfide 119 4.4.8 Mercuric trifluoroacetate 119 4.4.9 Iodine 120 4.4.10 Summary 122 4.5 Etching 122 4.5.1 Introduction 122 4.5.2 Plasma and ion etching 122 4.5.3 Solvent and chemical etching 125 4.5.4 Acid etching. 127 4.5.5 Summary 130 4.6 Replication 130 4.6.1 Simple replicas 131 4.6.2 Replication for TEM 132 4.7 Conductive coatings 136 4.7.1 Coating devices 136 4.7.2 Coatings for TEM 137 4.7.3 Coatings for SEM and STM 138 4.7.4 Artifacts 141 4.7.5 Gold decoration 146 4.8 Yielding and fracture 147 4.8.1 Fractography 147
viii Contents 4.8.2 Fracture: standard physical testing 148 4.8.3 In situ deformation 152 4.8.4 Crazing 154 4.9 Freezing and drying methods 157 4.9.1 Simple freezing methods 158 4.9.2 Freeze drying 158 4.9.3 Critical point drying 161 4.9.4 Freeze fracture-etching 163 5 Polymer applications 174 5.1 Fibers 174 5.1.1 Introduction 174 5.1.2 Textile fibers 175 5.1.3 Problem solving applications 183 5.1.4 Industrial fibers 192 5.2 Films and membranes 197 5.2.1 Introduction. 197 5.2.2 Model studies 198 5.2.3 Industrial films 202 5.2.4 Hat film membranes 208 5.2.5 Hollow fiber membranes 218 5.3 Engineering resins and plastics 219 5.3.1 Introduction 219 5.3.2 Extrudates and molded parts 221 5.3.3 Multiphase polymers 229 5.3.4 Failure analysis 244 5.4 Composites ; 247 5.4.1 Introduction 247 5.4.2 Composite characterization 248 5.4.3 Fiber composites 251 5.4.4 Particle filled composites 257 5.4.5 Carbon black filled rubber 261 5.5 Emulsions and adhesives 264 5.5.1 Introduction 264 5.5.2 Latexes 264 5.5.3 Wettability 271 5.5.4 Adhesives and adhesion 272 5.6 Liquid crystalline polymers 275 5.6.1 Introduction 275 5.6.2 Optical textures 277 5.6.3 Solid state structures 280 5.6.4 High modulus fibers 287 5.6.5 Structure-property relations in LCPs 293
ix 6 New techniques in polymer microscopy 315 6.1 Introduction 315 6.2 Optical microscopy 315 6.2.1 Confocal scanning microscopy 315 6.2.2 Near field optical microscopy 318 6.3 Scanning electron microscopy (SEM) 319 6.3.1 Low voltage SEM 319 6.3.2 High resolution SEM 325 6.3.3 High pressure (environmental) SEM 326 6.4 Transmission electron microscopy (TEM) 327 6.4.1 High resolution TEM 327 6.4.2 Structure determination by electron diffraction 331 6.5 Scanning tunneling microscopy (STM) 332 6.5.1 Principles of STM 332 6.5.2 Instrumentation and operation of the STM 334 6.5.3 STM of insulators 336 6.5.4 Adsorbed organic molecules 337 6.5.5 Other polymer applications 339 6.6 Scanning "force microscopy (SFM) 339 6.6.1 Principles of atomic force microscopy (AFM) 340 6.6.2 Atomic resolution in the AFM 343 6.6.3 Metrology using scanning probe microscopy 346 6.6.4 Frictional force microscopy 350 7 Problem solving summary 357 7.1 Where to start 357 7.1.1 Problem solving protocol 358 7.1.2 Polymer structures \ 358 7.2 Instrumental techniques 359 7.2.1 Comparison of techniques 360 7.2.2 Optical techniques 362 7.2.3 SEM techniques 363 7.2.4 TEM techniques 364 7.2.5 SPM techniques 365 7.2.6 Technique selection 365 7.3 Interpretation 365 7.3.1 Artifacts 366 7.3.2 Summary 368 7.4 Supporting characterizations 369 7.4.1 X-ray diffraction 369 7.4.2 Thermal analysis 371 7.4.3 Spectroscopy 372 7.4.4 Small angle scattering 374 7.4.5 Summary 375
Appendices 379 Appendix I Abbreviations of polymer names 379 Appendix II List of acronyms - techniques 380 Appendix III Manmade polymer fibres 381 Appendix IV Common commercial polymers and tradenames for plastics, films and engineering resins 382 Appendix V General suppliers of microscopy accessories 384 Appendix VI Suppliers of optical and electron microscopes 385 Appendix VII Suppliers of x-ray microanalysis equipment 385 Appendix VIII Suppliers of scanning probe microscopes 386 Index 387