Hydrogel Sensors and Actuators (eBook)

Gerald Gerlach: 1983, 1987 Diploma and doctoral degree in EE from Technische Universität Dresden, Germany, respectively R&D engineer in measuring devices industry Since 1993 Professor for Microtechnology, since 1996 Professor for Solid State Electronics in EE department of TU Dresden 2001/02 Visiting professor at UCLA Since 2002 Member of the Executive of VDE (German Association of Engineers in Electrical Engineering, Electronics, Information Technology since 2007 Chairperson of the German Society for Measurement and Automatic Control (GMA) Since 1996 Conference Chairman of the biannually organised International Conference „Infrared Sensors and Systems IRS2" in Nuremberg (in conjunction with the world’s largest sensor exhibition "Sensor+Test") 2008 General Chairman of the Eurosensors XXII Conference, Dresden Author and Co-author of some 280 scientific journal and international conference papers, holds 38 patents (8 more pending) Karl-Friedrich Arndt: 1971 Diploma degree in physics from TU Dresden, 1975 PhD and 1982 Dr.rer.nat.habil from TH Merseburg (Physical Chemistry, Polymer Characterization); post-doc: Institute of Macromolecular Chemistry Prague (1982/1983), Department of Physics University of Gdansk (1983, 1984, 1985), Since 1990 full professor full of Physical Chemistry of Polymers at TU Dresden Visiting professor at Philipps-Universität Marburg (1990) and at UABC Tijuana/Centro Graduados e Ivestigación de Tijuana, Mexico) (1997, 1999, 2001, 2003, 2005, 2006); Author and Co-author of 150 peer-reviewed papers, about 100 conference papers, 3 text books on polymer characterization (Hanser), revision of "Dictionary of Chemistry and Chemical Technology" (Langenscheidt), holds 24 patents

152490_1_En_FM1_OnlinePDF.pdf 2
152490_1_En_1_Chapter_OnlinePDF.pdf 11
Chapter : General Properties of Hydrogels 11
Introduction 12
Swelling and Elasticity of Hydrogels 13
Inhomogeneity of Hydrogels 18
Hydrogels with Improved Properties 20
References 22
152490_1_En_2_Chapter_OnlinePDF.pdf 25
Chapter : Synthesis of Hydrogels 25
Chemical Cross-Linking 29
Temperature Dependent Swelling 29
pH-Dependent Swelling 32
Bi-Responsive Materials 33
Polymerisation and Cross-Linking 35
Effect of Synthesis Temperature 36
Effect of Solvent 37
Effect of Cross-Linker Concentration 37
Effect of Monomer Concentration 37
Morphological Characterization and Photo Patterning 38
Generation of Hydrogel Patterns 38
Cross-Linking and Patterning by Irradiation 41
Sol-Gel Analysis 41
Radiation Source 44
Radiochemical Synthesis of Hydrogels 48
Examples of Gel Synthesis 49
Patterning 56
Gel Point Determination of the Reversible Gelatin Gelling System 61
Gel Point 61
Gel Point Determination Methods 62
Dynamic Light Scattering 62
Oscillatory shear rheology 63
Gelatin as Example for Reversible Gelation 64
Critical Dynamical Exponents for the Gelation Threshold of Gelatin 65
Conclusions 68
References 71
152490_1_En_3_Chapter_OnlinePDF.pdf 78
Chapter : Swelling-Related Processes in Hydrogels 78
Thermodynamics of Swelling 83
Chemical Potential and Equilibrium Degree of Swelling 83
Flory-Rehner Theory, Mixing Part 84
Flory-Rehner Theory, Elastic Part 84
Discussion of Flory-Rehner Equation 92
Mechanical Power Generation on Example of PVA-PAAc gel 96
Kinetics of Swelling 97
Diffusion 97
Cooperative Diffusion Coefficient 99
Time Dependence of the Degree of Swelling 101
Volume Phase Transition 105
Gels with Fast Response 108
Determination of Dcoop of Polyelectrolyte Hydrogels by DLS 109
Characterization of Molecular Processes 111
Fourier Transform Infrared Spectroscopy and Raman Spectroscopy 111
3.1.1Introduction 111
3.1.2Fourier Transform Infrared Spectroscopy 111
3.1.3Raman Spectroscopy 111
3.1.4Sample Preparation 111
Sampling Techniques for FT-IR Spectroscopy 88
Deuterium Oxide Instead Water? 111
Sampling Techniques for Raman Spectroscopy 120
3.1.5Qualitative Spectral Interpretation 111
General Approaches 121
The Region 2,000-3,800cm-1 122
The Region 900-2,000cm-1 122
The Region 500-900cm-1 124
3.1.6FT-IR and Raman Spectra of Hydrogels 111
3.1.7FT-IR and Raman spectroscopic imaging 111
FT-IR and Raman Imaging Spectrometer 132
Enhanced Data Analysis and Imaging Evaluation 133
NMR Imaging 135
3.2.1Application on Network Characterization 111
3.2.2Principle of NMR Imaging 111
3.2.3Examples 111
Monitoring of Transport Processes 138
Transport Processes for Drug Release 138
Volume Phase Transition of a Temperature Sensitive Hydrogel 139
Diffusion of Small Molecules into a Swollen Hydrogel 139
Distribution of Swelling Agent inside a Swollen Gel 140
References 142
152490_1_En_4_Chapter_OnlinePDF.pdf 146
Chapter : Modelling and Simulation of the Chemo-Electro-Mechanical Behaviour 146
Modelling on Different Scales 150
Statistical Theory 151
Porous Media Theory 155
Coupled Chemo-Electro-Mechanical Model 157
Chemical Field 158
Electrical Field 158
Mechanical Field 159
Coupling of the Involved Fields 159
Discrete Element Model 161
Coupled Chemo-Electro-Mechanical Model 162
Discretisation 162
Coupling Schemes 163
Numerical Simulation of the Chemo-Electrical Field 164
Chemical Stimulation 165
Electrical Stimulation 166
Numerical Simulation of the Chemo-Electro-Mechanical Field 167
Chemical Stimulation 167
Electrical Stimulation 168
Mechanical Stimulation 168
Comparison with Experimental Results 169
Conclusions and Outlook 170
References 171
152490_1_En_5_Chapter_OnlinePDF.pdf 173
Chapter : Hydrogels for Chemical Sensors 173
Hydrogel-Based Piezoresistive Chemical Sensors 176
Operational Principle 176
Sensor Design 177
Sensor Calibration 178
Hydrogel Material Preparation and Characterization 179
Thermally Cross-Linked Poly(vinyl Alcohol)/Poly(Acrylic Acid) Blend 180
Chemically Cross-Linked N-Isopropylacrylamide 180
Photo Cross-Linkable Copolymers 181
Materials 181
P2VP-block-P(NIPAAm-co-DMIAAm) block copolymer 181
PNIPAAm-DMAAm-DMIAAm terpolymer 182
PDMAEMA-DMIMA copolymer 182
Polymer characterization 182
UV Cross-Linking 183
Hydrogel Conditioning 183
Temperature Sensitivity of PNIPAAm Gels 184
pH Sensors 185
Sensitivity 186
Response Time 188
Signal Reproducibility 190
Sensors for Concentration Measurements in Aqueous Solutions 192
Sensors for Organic Solvents 193
Sensors for Salt Concentrations 196
Sensors for Metal Ions Concentrations 196
Summary 200
References 201
152490_1_En_6_Chapter_OnlinePDF.pdf 204
Chapter : Hydrogels for Biosensors 204
Introduction 206
Biosensor Devices 207
Enzyme Biosensors 208
Immobilization of Enzymes and Whole Cells Via Hydrogel Encapsulation 209
Whole-Cell-Based Hydrogel Biosensors 210
Amperometric Biosensors 212
Redox Polymers 213
Multi-Analyte Monitoring Devices 215
Characterization of the Stability of Entrapped Enzymes 217
Nanocalorimetry 220
Smart Hydrogels for Biosensors 222
Summary 224
References 224
152490_1_En_7_Chapter_OnlinePDF.pdf 228
Chapter : Hydrogels for Actuators 228
Introduction 230
Automatic Microfluidic Systems 231
Hydrodynamic Transistors 232
Directly Acting Hydrogel Component 232
Hydrogel as Servo Drive 233
Normally Closed and Normally Open Valves 234
Mechanical Adjustability of the Regulation Point 235
Fluidic Propulsion 236
Chemostat Pumps 236
Autonomous Pumps 237
Tunable Micro-Lenses 238
Microelectromechanical Microfluidic Systems 239
Electrothermic and Optoelectrothermic Interface 240
Microvalves 241
Micropumps 242
Diffusion Pumps 242
Displacement Micropumps 243
Hydrodynamic Microtransistors 244
High Resolution Tactile Displays 245
Influence of Material and Phase Transition Phenomena on the Operational Characteristics of Hydrogel Elements 246
Effects at the Initialisation of Gel Elements 246
Conditioning Effect 247
Softening Effect 247
Volume Change After Polymerisation 247
Phenomena at the Volume Phase Transition of Gels 247
Intrinsic Shrinkage Barrier Effect 247
Extrinsic Shrinkage Barrier Effect 248
Two-Step Mechanism of the Volume Phase Transition 248
Screening Effect 249
Material Enrichment Inside the Hydrogel 249
Design and Performance 250
Response Time 250
Effective Diffusion Length 250
Swelling Agent Supply 250
Counterforces 251
Recirculation of Process Media 251
Pressure Resistance and Particle Tolerance 251
References 252
152490_1_En_8_Chapter_OnlinePDF.pdf 256
Chapter : Polymer Hydrogels to Enable New Medical Therapies 256
Hydrogels in Biomedical Applications 257
Thermo-Responsive Cell Culture Carriers 259
Biohybrid Cell Scaffolds for In Vivo Tissue Engineering 263
Summary and Perspective 269
References 270
152490_1_En_BM2_OnlinePDF.pdf 274
: Index 274