The development of new multifunctional membranes and materials which respond to external stimuli, such as pH, temperature, light, biochemicals or magnetic or electrical signals, represents new approaches to separations, reactions, or recognitions. With multiple cooperative functions, responsive membranes and materials have applications which range from biopharmaceutical, to drug delivery systems to water treatment. This book covers recent advances in the generation and application of responsive materials and includes: Development and design of responsive membranes and materials Carbon nanotube membranes Tunable separations, reactions and nanoparticle synthesis Responsive membranes for water treatment Pore-filled membranes for drug release Biologically-inspired responsive materials and hydrogels Biomimetic polymer gels Responsive Membranes and Materials provides a cutting-edge resource for researchers and scientists in membrane science and technology, as well as specialists in separations, biomaterials, bionanotechnology, drug delivery, polymers, and functional materials.

Table of Contents:
Preface xv List of Contributors xxi 1 Oligonucleic Acids (“Aptamers”) for Designing Stimuli-Responsive Membranes 1 Veli Cengiz O¨ zalp, Mar´ýa Bele´n Serrano-Santos and Thomas Scha¨fer 1.1 Introduction 1 1.2 Aptamers – Structure, Function, Incorporation, and Selection 4 1.3 Characterization Techniques for Aptamer-Target Interactions 7 1.3.1 Measuring Overall Structural Changes of Aptamers Using QCM-D 8 1.3.2 Measuring Overall Structural Changes of Aptamers Using DPI 13 1.4 Aptamers – Applications 17 1.4.1 Electromechanical Gates 17 1.4.2 Stimuli-Responsive Nucleic Acid Gates in Nanoparticles 17 1.4.3 Stimuli-Responsive Aptamer Gates in Nanoparticles 20 1.4.4 Stimuli-Responsive Aptamer-Based Gating Membranes 22 1.5 Outlook 25 Acknowledgements 26 References 26 2 Emerging Membrane Nanomaterials – Towards Natural Selection of Functions 31 Mihail Barboiu 2.1 Introduction 31 2.2 Ion-Pair Conduction Pathways in Liquid and Hybrid Membranes 32 2.3 Dynamic Insidepore Resolution Towards Emergent Membrane Functions 36 2.4 Dynameric Membranes and Materials 39 2.4.1 Constitutional Hybrid Materials 39 2.4.2 Dynameric Membranes Displaying Tunable Properties on Constitutional Exchange 41 2.5 Conclusion 46 Acknowledgements 47 References 47 3 Carbon Nanotube Membranes as an Idealized Platform for Protein Channel Mimetic Pumps 51 Bruce Hinds 3.1 Introduction 51 3.2 Experimental Understanding of Mass Transport Through CNTs 56 3.2.1 Ionic Diffusion and Gatekeeper Activity 57 3.2.2 Gas and Fluid Flow 57 3.3 Electrostatic Gatekeeping and Electro-osmotic Pumping 59 3.3.1 Biological Gating 62 3.4 CNT Membrane Applications 63 3.5 Conclusion and Future Prospects 66 Acknowledgements 67 References 67 4 Synthesis Aspects in the Design of Responsive Membranes 73 Scott M. Husson 4.1 Introduction 73 4.2 Responsive Mechanisms 74 4.3 Responsive Polymers 75 4.3.1 Temperature-Responsive Polymers 75 4.3.2 Polymers that Respond to pH, Ionic Strength, Light 76 4.4 Preparation of Responsive Membranes 77 4.5 Polymer Processing into Membranes 78 4.5.1 Solvent Casting 78 4.5.2 Phase Inversion 78 4.6 In Situ Polymerization 78 4.6.1 Radiation-Based Methods 78 4.6.2 Interpenetrating Polymer Networks (IPNs) 79 4.7 Surface Modification Using Stimuli-Responsive Polymers 79 4.8 “Grafting to” Methods 81 4.8.1 Physical Adsorption – Non-covalent 81 4.8.2 Chemical Grafting – Covalent 81 4.8.3 Surface Entrapment – Non-covalent, Physically Entangled 82 4.9 “Grafting from” – a.k.a. Surface-Initiated Polymerization 83 4.9.1 Photo-Initiated Polymerization 83 4.9.2 Atom Transfer Radical Polymerization 85 4.9.3 Reversible Addition-Fragmentation Chain Transfer Polymerization 87 4.9.4 Other Grafting Methods 91 4.9.5 Summary of “Grafting from” Methods 91 4.10 Future Directions 91 References 92 5 Tunable Separations, Reactions, and Nanoparticle Synthesis in Functionalized Membranes 97 Scott R. Lewis, Vasile Smuleac, Li Xiao and D. Bhattacharyya 5.1 Introduction 97 5.2 Membrane Functionalization 98 5.2.1 Chemical Modification 98 5.2.2 Surface Initiated Membrane Modification 101 5.2.3 Cross-Linked Hydrogel (Pore Filled) Membranes 102 5.2.4 Layer by Layer Assemblies 103 5.3 Applications 104 5.3.1 Water Flux Tunability 104 5.3.2 Tunable Separation of Salts 109 5.3.3 Charged-Polymer Multilayer Assemblies for Environmental Applications 113 5.4 Responsive Membranes and Materials for Catalysis and Reactions 115 5.4.1 Iron-Functionalized Responsive Membranes 116 5.4.2 Responsive Membranes for Enzymatic Catalysis 127 Acknowledgements 132 References 132 6 Responsive Membranes for Water Treatment 143 Qian Yang and S. R. Wickramasinghe 6.1 Introduction 143 6.2 Fabrication of Responsive Membranes 144 6.2.1 Functionalization by Incubation in Liquids 145 6.2.2 Functionalization by Incorporation of Responsive Groups in the Base Membrane 145 6.2.3 Surface Modification of Existing Membranes 148 6.3 Outlook 158 References 159 7 Functionalization of Polymeric Membranes and Feed Spacers for Fouling Control in Drinking Water Treatment Applications 163 Colleen Gorey, Richard Hausman and Isabel C. Escobar 7.1 Membrane Filtration 163 7.2 Fouling 165 7.3 Improving Membrane Performance 168 7.3.1 Plasma Treatment 168 7.3.2 Ultraviolet (UV) Irradiation 170 7.3.3 Membrane Modification by Graft Polymerization 171 7.3.4 Ion Beam Irradiation 176 7.4 Design and Surface Modifications of Feed Spacers for Biofouling Control 178 7.5 Conclusion 180 Acknowledgements 181 References 181 8 Pore-Filled Membranes as Responsive Release Devices 187 Kang Hu and James Dickson 8.1 Introduction 187 8.2 Responsive Pore-Filled Membranes 188 8.3 Development and Characterization of PVDF-PAA Pore-Filled pH-Sensitive Membranes 190 8.3.1 Membrane Gel Incorporation (Mass Gain) 191 8.3.2 Membrane pH Reversibility 191 8.3.3 Membrane Water Flux as pH Varied from 2 to 7.5 191 8.3.4 Effects of Gel Incorporation on Membrane Pure Water Permeabilities at pH Neutral and Acidic 195 8.3.5 Estimation and Calculation of Pore Size 198 8.4 pH-Sensitive Poly(Vinylidene Fluoride)-Poly(Acrylic Acid) Pore-Filled Membranes for Controlled Drug Release in Ruminant Animals 201 8.4.1 Determination of Membrane Diffusion Permeability (PS) for Salicylic Acid 202 8.4.2 Applicability of the Fabricated Pore-Filled Membranes on the Salicylic Acid Release and Retention 205 References 207 9 Magnetic Nanocomposites for Remote Controlled Responsive Therapy and in Vivo Tracking 211 Ashley M. Hawkins, David A. Puleo and J. Zach Hilt 9.1 Introduction 211 9.1.1 Nanocomposite Polymers 211 9.1.2 Magnetic Nanoparticles 212 9.2 Applications of Magnetic Nanocomposite Polymers 212 9.2.1 Thermal Actuation 213 9.2.2 Thermal Therapy 218 9.2.3 Mechanical Actuation 220 9.2.4 In Vivo Tracking and Applications 224 9.3 Concluding Remarks 224 References 224 10 The Interactions between Salt Ions and Thermo-Responsive Poly (N-Isopropylacrylamide) from Molecular Dynamics Simulations 229 Hongbo Du and Xianghong Qian 10.1 Introduction 229 10.2 Computational Details 230 10.3 Results and Discussion 232 10.4 Conclusion 238 Acknowledgements 240 References 240 11 Biologically-Inspired Responsive Materials: Integrating Biological Function into Synthetic Materials 243 Kendrick Turner, Santosh Khatwani and Sylvia Daunert 11.1 Introduction 243 11.2 Biomimetics in Biotechnology 245 11.3 Hinge-Motion Binding Proteins 249 11.4 Calmodulin 250 11.5 Biologically-Inspired Responsive Membranes 251 11.6 Stimuli-Responsive Hydrogels 253 11.7 Micro/Nanofabrication of Hydrogels 255 11.8 Mechanical Characterization of Hydrogels 256 11.9 Creep Properties of Hydrogels 257 11.10 Conclusion and Future Perspectives 258 Acknowledgements 258 References 258 12 Responsive Colloids with Controlled Topology 269 Jeffrey C. Gaulding, Emily S. Herman and L. Andrew Lyon 12.1 Introduction 269 12.2 Inert Core/Responsive Shell Particles 270 12.3 Responsive Core/Responsive Shell Particles 275 12.4 Hollow Particles 281 12.5 Janus Particles 286 12.6 Summary 292 References 293 13 Novel Biomimetic Polymer Gels Exhibiting Self-Oscillation 301 Ryo Yoshida 13.1 Introduction 301 13.2 The Design Concept of Self-Oscillating Gel 303 13.3 Aspects of the Autonomous Swelling–Deswelling Oscillation 303 13.4 Design of Biomimetic Actuator Using Self-Oscillating Polymer and Gel 306 13.4.1 Ciliary Motion Actuator (Artificial Cilia) 306 13.4.2 Self-Walking Gel 307 13.4.3 Theoretical Simulation of the Self-Oscillating Gel 307 13.5 Mass Transport Surface Utilizing Peristaltic Motion of Gel 308 13.6 Self-Oscillating Polymer Chains and Microgels as “Nanooscillators” 309 13.6.1 Solubility Oscillation of Polymer Chains 309 13.6.2 Self-Flocculating/Dispersing Oscillation of Microgels 310 13.6.3 Viscosity Oscillation of Polymer Solution and Microgel Dispersion 311 13.6.4 Attempts of Self-Oscillation under Acid- and Oxidant-Free Physiological Conditions 311 13.7 Conclusion 312 References 312 14 Electroactive Polymer Soft Material Based on Dielectric Elastomer 315 Liwu Liu, Zhen Zhang, Yanju Liu and Jinsong Leng 14.1 Introduction to Electroactive Polymers 315 14.1.1 Development History 316 14.1.2 Classification 316 14.1.3 Electronic Electroactive Polymers 316 14.1.4 Ionic Electroactive Polymers 318 14.1.5 Electroactive Polymer Applications 318 14.1.6 Application of Dielectric Elastomers 318 14.1.7 Manufacturing the Main Structure of Actuators Using EAP Materials 327 14.1.8 The Current Problem for EAP Materials and their Prospects 329 14.2 Materials of Dielectric Elastomers 330 14.2.1 The Working Principle of Dielectric Elastomers 330 14.2.2 Material Modification of Dielectric Elastomer 331 14.2.3 Dielectric Elastomer Composite 334 14.3 The Theory of Dielectric Elastomers 336 14.3.1 Free Energy of Dielectric Elastomer Electromechanical Coupling System 336 14.3.2 Special Elastic Energy 339 14.3.3 Special Electric Field Energy 341 14.3.4 Incompressible Dielectric Elastomer 342 14.3.5 Model of Several Dielectric Elastomers 342 14.4 Failure Model of a Dielectric Elastomer 356 14.4.1 Electrical Breakdown 357 14.4.2 Electromechanical Instability and Snap-Through Instability 357 14.4.3 Loss of Tension 358 14.4.4 Rupture by Stretching 359 14.4.5 Zero Electric Field Condition 359 14.4.6 Super-Electrostriction Deformation of a Dielectric Elastomer 359 14.5 Converter Theory of Dielectric Elastomer 361 14.5.1 Principle for Conversion Cycle 361 14.5.2 Plane Actuator 362 14.5.3 Spring-Roll Dielectric Elastomer Actuator 364 14.5.4 Tube-Type Actuator 365 14.5.5 Film-Spring System 369 14.5.6 Energy Harvester 372 14.5.7 The Non-Linear Vibration of a Dielectric Elastomer Ball 376 14.5.8 Folded Actuator 377 References 379 15 Responsive Membranes/Material-Based Separations: Research and Development Needs 385 Rosemarie D. Wesson, Elizabeth S. Dow and Sonya R. Williams 15.1 Introduction 385 15.2 Water Treatment 386 15.3 Biological Applications 387 15.4 Gas Separation and Additional Applications 388 References 389 Index 395