Polymer and biopolymer brushes: for materials science and biotechnology

Volume 1 Preface xxi List of Contributors xxiii 1 Functionalization of Surfaces Using Polymer Brushes: An Overview of Techniques, Strategies, and Approaches 1Juan M. Giussi,M. Lorena Cortez,Waldemar A. Marmisolle, and Omar Azzaroni 1.1 Introduction: Fundamental Notions and Concepts 1 1.2 Preparation of Polymer Brushes on Solid Substrates 4 1.3 Preparation of Polymer Brushes by the "Grafting-To" Method 5 1.4 Polymer Brushes by the "Grafting-From" Method 9 1.4.1 Surface-Initiated Atom Transfer Radical Polymerization 9 1.4.2 Surface-Initiated Reversible-Addition Fragmentation Chain Transfer Polymerization 10 1.4.3 Surface-Initiated Nitroxide-Mediated Polymerization 13 1.4.4 Surface-Initiated Photoiniferter-Mediated Polymerization 13 1.4.5 Surface-Initiated Living Ring-Opening Polymerization 15 1.4.6 Surface-Initiated Ring-Opening Metathesis Polymerization 17 1.4.7 Surface-Initiated Anionic Polymerization 18 1.5 Conclusions 20 Acknowledgments 21 References 21 2 Polymer Brushes by AtomTransfer Radical Polymerization 29Guojun Xie, Amir Khabibullin, Joanna Pietrasik, Jiajun Yan, and KrzysztofMatyjaszewski 2.1 Structure of Brushes 29 2.2 Synthesis of Polymer Brushes 31 2.2.1 Grafting through 31 2.2.2 Grafting to 32 2.2.3 Grafting from 32 2.3 ATRP Fundamentals 33 2.4 Molecular Bottlebrushes by ATRP 38 2.4.1 Introduction 38 2.4.2 Star-Like Brushes 40 2.4.3 Blockwise Brushes 42 2.4.4 Brushes with Tunable Grafting Density 45 2.4.5 Brushes with Block Copolymer Side Chains 46 2.4.6 Functionalities and Properties of Brushes 50 2.5 ATRP and Flat Surfaces 55 2.5.1 Chemistry at Surface 55 2.5.2 Grafting Density 55 2.5.3 Architecture 56 2.5.4 Applications 57 2.6 ATRP and Nanoparticles 58 2.6.1 Chemistry 58 2.6.2 Architecture 59 2.6.3 Applications 61 2.7 ATRP and Concave Surfaces 63 2.8 ATRP and Templates 63 2.8.1 Templates from Networks 63 2.8.2 Templates from Brushes 64 2.9 Templates from Stars 65 2.10 Bio-Related Polymer Brushes 66 2.11 Stimuli-Responsive Polymer Brushes 74 2.11.1 Stimuli-Responsive Solutions 76 2.11.2 Stimuli-Responsive Surfaces 78 2.12 Conclusion 79 Acknowledgments 80 References 80 3 Polymer Brushes by Surface-Mediated RAFT Polymerization for Biological Functions 97Tuncer Caykara 3.1 Introduction 97 3.2 Polymer Brushes via the Surface-Initiated RAFT Polymerization Process 99 3.3 Polymer Brushes via the Interface-Mediated RAFT Polymerization Process 101 3.3.1 pH-Responsive Brushes 102 3.3.2 Temperature-Responsive Brushes 106 3.3.3 Polymer Brushes on Gold Surface 110 3.3.4 Polymer Brushes on Nanoparticles 114 3.3.5 Micropatterned Polymer Brushes 115 3.4 Summary 117 References 119 4 Electro-Induced Copper-Catalyzed Surface Modification with Monolayer and Polymer Brush 123Bin Li and Feng Zhou 4.1 Introduction 123 4.2 "Electro-Click" Chemistry 124 4.3 Electrochemically Induced Surface-Initiated Atom Transfer Radical Polymerization 129 4.4 Possible Combination of eATRP and "e-Click" Chemistry on Surface 136 4.5 Surface Functionality 136 4.6 Summary 137 Acknowledgments 138 References 138 5 Polymer Brushes on Flat and Curved Substrates:What Can be Learned fromMolecular Dynamics Simulations 141K. Binder, S.A. Egorov, and A.Milchev 5.1 Introduction 141 5.2 Molecular Dynamics Methods: A Short "Primer" 144 5.3 The Standard Bead Spring Model for Polymer Chains 148 5.4 Cylindrical and Spherical Polymer Brushes 150 5.5 Interaction of Brushes with Free Chains 152 5.6 Summary 153 Acknowledgments 156 References 157 6 Modeling of Chemical Equilibria in Polymer and Polyelectrolyte Brushes 161Rikkert J. Nap,Mario Tagliazucchi, Estefania Gonzalez Solveyra, Chun-lai Ren, Mark J. Uline, and Igal Szleifer 6.1 Introduction 161 6.2 Theoretical Approach 163 6.3 Applications of the Molecular Theory 177 6.3.1 Acid-Base Equilibrium in Polyelectrolyte Brushes 178 6.3.1.1 Effect of Salt Concentration and pH 178 6.3.1.2 Effect of Polymer Density and Geometry 184 6.3.2 Competition between Chemical Equilibria and Physical Interactions 186 6.3.2.1 Brushes of Strong Polyelectrolytes 186 6.3.2.2 Brushes ofWeak Polyelectrolytes: Self-Assembly in Charge-Regulating Systems 189 6.3.2.3 Redox-Active Polyelectrolyte Brushes 193 6.3.3 End-Tethered Single Stranded DNA in Aqueous Solutions 195 6.3.4 Ligand-Receptor Binding and Protein Adsorption to Polymer Brushes 201 6.3.5 Adsorption Equilibrium of Polymer Chains through Terminal Segments: Grafting-to Formation of Polymer Brushes 207 6.4 Summary and Conclusion 212 Acknowledgments 216 References 216 7 Brushes of Linear and Dendritically Branched Polyelectrolytes 223E. B. Zhulina, F. A. M. Leermakers, and O. V. Borisov 7.1 Introduction 223 7.2 Analytical SCF Theory of Brushes Formed by Linear and Branched Polyions 224 7.2.1 Dendron Architecture and System Parameters 225 7.2.2 Analytical SCF Formalism 226 7.3 Planar Brush of PE Dendrons with an Arbitrary Architecture 229 7.3.1 Asymptotic Dependences for Brush Thickness H 231 7.4 Planar Brush of Star-Like Polyelectrolytes 232 7.5 Threshold of Dendron Gaussian Elasticity 234 7.6 Scaling-Type Diagrams of States for Brushes of Linear and Branched Polyions 235 7.7 Numerical SF-SCF Model of Dendron Brush 236 7.8 Conclusions 238 References 239 8 Vapor Swelling of Hydrophilic Polymer Brushes 243Casey J. Galvin and Jan Genzer 8.1 Introduction 243 8.2 Experimental 245 8.2.1 General Methods 245 8.2.2 Synthesis of Poly((2-dimethylamino)ethyl methacrylate) Brushes with a Gradient in Grafting Density 245 8.2.3 Synthesis of Poly(2-(diethylamino)ethyl methacrylate) Brushes 245 8.2.4 Chemical Modification of Poly((2-dimethylamino)ethyl methacrylate) Brushes 246 8.2.5 Bulk Synthesis of PDMAEMA 246 8.2.6 Preparation of Spuncast PDMAEMA Films 246 8.2.7 Chemical Modification of Spuncast PDMAEMA Film 247 8.2.8 Spectroscopic EllipsometryMeasurements under Controlled Humidity Conditions 247 8.2.9 Spectroscopic EllipsometryMeasurements of Alcohol Exposure 247 8.2.10 Fitting Spectroscopic Ellipsometry Data 248 8.2.11 Infrared Variable Angle Spectroscopic Ellipsometry 248 8.3 Results and Discussion 248 8.3.1 Comparing Polymer Brush and Spuncast Polymer Film Swelling 250 8.3.2 Influence of Side Chain Chemistry on Polymer Brush Vapor Swelling 252 8.3.3 Influence of Solvent Vapor Chemistry on Polymer Brush Vapor Swelling 256 8.3.4 Influence of Grafting Density on Polymer Brush Vapor Swelling 259 8.4 Conclusion 262 8.A.1 Appendix 263 8.A.1.1 Mole Fraction Calculation 263 8.A.1.2 Water Cluster Number Calculation 264 Acknowledgments 265 References 265 9 Temperature Dependence of the Swelling and Surface Wettability of Dense Polymer Brushes 267Pengyu Zhuang, Ali Dirani, Karine Glinel, and AlainM. Jonas 9.1 Introduction 267 9.2 The Swelling Coefficient of a Polymer Brush Mirrors Its Volume Hydrophilicity 269 9.3 The Cosine of the Contact Angle ofWater on aWater-Equilibrated Polymer Brush Defines Its Surface Hydrophilicity 270 9.4 Case Study: Temperature-Dependent Surface hydrophilicity of Dense PNIPAM Brushes 272 9.5 Case Study: Temperature-Dependent Swelling and Volume Hydrophilicity of Dense PNIPAMBrushes 274 9.6 Thermoresponsive Poly(oligo(ethylene oxide)methacrylate) Copolymer Brushes: Versatile Functional Alternatives to PNIPAM 277 9.7 Surface and Volume Hydrophilicity of Nonthermoresponsive Poly(oligo(ethylene oxide)methacrylate) Copolymer Brushes 279 9.8 Conclusions 282 Acknowledgments 283 References 283 10 Functional Biointerfaces Tailored by "Grafting-To"Brushes 287Eva Bittrich, Manfred Stamm, and Petra Uhlmann 10.1 Introduction 287 10.2 Part I: Polymer Brush Architectures 288 10.2.1 Design of Physicochemical Interfaces by Polymer Brushes 288 10.2.1.1 Stimuli-Responsive Homopolymer Brushes 288 10.2.1.2 Combination of Responses Using Mixed Polymer Brushes 290 10.2.1.3 Stimuli-Responsive Gradient Brushes 293 10.2.2 Modification of Polymer Brushes by Click Chemistry 293 10.2.2.1 Definition of Click Chemistry 293 10.2.2.2 Modification of End Groups of Grafted PNIPAAm Chains 295 10.2.3 Hybrid Brush Nanostructures 297 10.2.3.1 Nanoparticles Immobilized at Polymer Brushes 298 10.2.3.2 Sculptured Thin Films Grafted with Polymer Brushes 300 10.3 Part II: Actuating Biomolecule Interactions with Surfaces 303 10.3.1 Adsorption of Proteins to Polymer Brush Surfaces 303 10.3.1.1 Calculation of the Adsorbed Amount of Protein from Ellipsometric Experiments 305 10.3.1.2 Preventing Protein Adsorption 306 10.3.1.3 Adsorption at Polyelectrolyte Brushes 310 10.3.2 Polymer Brushes as Interfaces for Cell Adhesion and Interaction 313 10.3.2.1 Cell Adhesion on Stimuli-Responsive Polymer Surfaces Based on PNIPAAm Brushes 315 10.3.2.2 Growth Factors on Polymer Brushes 318 10.4 Conclusion and Outlook 320 Acknowledgments 321 References 321 11 Glycopolymer Brushes Presenting Sugars in Their Natural Form: Synthesis and Applications 333Kai Yu and Jayachandran N. Kizhakkedathu 11.1 Introduction and Background 333 11.2 Results and Discussion 334 11.2.1 Synthesis of Glycopolymer Brushes 334 11.2.1.1 Synthesis of N-Substituted Acrylamide Derivatives of Glycomonomers 334 11.2.1.2 Synthesis and Characterization of Glycopolymer Brushes on Gold Chip and SiliconWafer 334 11.2.1.3 Synthesis and Characterization of Glycopolymer Brushes on Polystyrene Particles 335 11.2.1.4 Synthesis and Characterization of Glycopolymer Brushes with Variation in the Composition of Carbohydrate Residues on SPR Chip 338 11.2.1.5 Preparation of Glycopolymer Brushes-Modified Particles with Different Grafting Density (Conformation) 338 11.2.2 Applications of Glycopolymer Brushes 341 11.2.2.1 Antithrombotic Surfaces Based on Glycopolymer Brushes 341 11.2.2.2 Glycopolymer Brushes Based Carbohydrate Arrays to Modulate Multivalent Protein Binding on Surfaces 345 11.2.2.3 Modulation of Innate Immune Response by the Conformation and Chemistry of Glycopolymer Brushes 351 11.3 Conclusions 356 Acknowledgments 357 References 357 12 Thermoresponsive Polymer Brushes for Thermally Modulated Cell Adhesion and Detachment 361Kenichi Nagase and Teruo Okano 12.1 Introduction 361 12.2 Thermoresponsive Polymer Hydrogel-Modified Surfaces for Cell Adhesion and Detachment 362 12.3 Thermoresponsive Polymer Brushes Prepared Using ATRP 363 12.4 Thermoresponsive Polymer Brushes Prepared by RAFT Polymerization 368 12.5 Conclusions 372 Acknowledgments 372 References 372 Volume 2 Preface xxi List of Contributors xxiii 13 Biomimetic Anchors for Antifouling Polymer Brush Coatings 377Dicky Pranantyo, Li Qun Xu, En-Tang Kang, Koon-Gee Neoh, and Serena Lay-Ming Teo 13.1 Introduction to Biofouling Management 377 13.2 Polymer Brushes for Surface Functionalization 378 13.3 Biomimetic Anchors for Antifouling Polymer Brushes 379 13.3.1 Mussel Adhesive-Inspired Dopamine Anchors 379 13.3.1.1 Antifouling Polymer Brushes Prepared via the "Grafting-To" Approach on (poly)Dopamine Anchor 383 13.3.1.2 Antifouling Polymer Brushes Prepared via the "Grafting-From" Approach on (poly)Dopamine Anchor 386 13.3.1.3 Direct Grafting of Antifouling Polymer Brushes Containing Anchorable Dopamine-Derived Functionalities 389 13.3.2 (Poly)phenolic Anchors for Antifouling Polymer Brushes 391 13.3.3 Biomolecular Anchors for Antifouling Polymer Brushes 393 13.4 Barnacle Cement as Anchor for Antifouling Polymer Brushes 397 13.5 Conclusion and Outlooks 399 References 400 14 Protein Adsorption Process Based on Molecular Interactions at Well-Defined Polymer Brush Surfaces 405Sho Sakata, Yuuki Inoue, and Kazuhiko Ishihara 14.1 Introduction 405 14.2 Utility of Polymer Brush Layers as Highly Controllable Polymer Surfaces 406 14.3 Performance of Polymer Brush Surfaces as Antifouling Biointerfaces 408 14.4 Elucidation of Protein Adsorption Based on Molecular Interaction Forces 412 14.5 Concluding Remarks 416 References 417 15 Are Lubricious Polymer Brushes Antifouling? Are Antifouling Polymer Brushes Lubricious? 421Edmondo M. Benetti and Nicholas D. Spencer 15.1 Introduction 421 15.2 Poly(ethylene glycol) Brushes 422 15.3 Beyond Simple PEG Brushes 424 15.4 Conclusion 429 References 429 16 Biofunctionalized Brush Surfaces for Biomolecular Sensing 433Shuaidi Zhang and Vladimir V. Tsukruk 16.1 Introduction 433 16.2 Biorecognition Units 435 16.2.1 Antibodies 435 16.2.2 Antibody Fragments 435 16.2.3 Aptamers 437 16.2.4 Peptide Aptamers 438 16.2.5 Enzymes 438 16.2.6 Peptide Nucleic Acid, Lectin, and Molecular Imprinted Polymers 439 16.3 Immobilization Strategy 439 16.3.1 Through Direct Covalent Linkage 440 16.3.1.1 Thiolated Aptamers on Noble Metal 440 16.3.1.2 General Activated Surface Chemistry 442 16.3.1.3 Diels-Alder Cycloaddition 444 16.3.1.4 Staudinger Ligation 444 16.3.1.5 1,3-Dipolar Cycloaddition 446 16.3.2 Through Affinity Tags 447 16.3.2.1 Biotin-Avidin/Streptavidin Pairing 447 16.3.2.2 NTA-Ni2+-Histidine Pairing 448 16.3.2.3 Protein A/Protein G - Fc Pairing 449 16.3.2.4 Oligonucleotide Hybridization 450 16.4 Microstructure and Morphology of Biobrush Layers 451 16.4.1 Grafting Density Control 451 16.4.2 Conformation and Orientation of Recognition Units 453 16.5 Transduction Schemes Based upon Grafted Biomolecules 462 16.5.1 Electrochemical-Based Sensors 462 16.5.2 Field Effect Transistor Based Sensors 463 16.5.3 SPR-Based Sensors 465 16.5.4 Photoluminescence-Based Sensors 466 16.5.5 SERS Sensors 468 16.5.6 Microcantilever Sensors 469 16.6 Conclusions 471 Acknowledgments 472 References 472 17 Phenylboronic Acid and Polymer Brushes: An Attractive Combination with Many Possibilities 479Solmaz Hajizadeh and Bo Mattiasson 17.1 Introduction: Polymer Brushes and Synthesis 479 17.2 Boronic Acid Brushes 481 17.3 Affinity Separation 483 17.4 Sensors 487 17.5 Biomedical Applications 492 17.6 Conclusions 494 References 494 18 Smart Surfaces Modified with Phenylboronic Acid Containing Polymer Brushes 497Hongliang Liu, ShutaoWang, and Lei Jiang 18.1 Introduction 497 18.2 Molecular Mechanism of PBA-Based Smart Surfaces 498 18.3 pH-Responsive Surfaces Modified with PBA Polymer Brush and Their Applications 501 18.4 Sugar-Responsive SurfacesModified with PBA Polymer Brush and Their Applications 503 18.5 PBA Polymer Brush-Based pH/Sugar Dual-Responsive OR Logic Gates and Their Applications 504 18.6 PBA Polymer Brush-Based pH/Sugar Dual-Responsive AND Logic Gates and Their Applications 506 18.7 PBA-Based Smart Systems beyond Polymer Brush and Their Applications 509 18.8 Conclusion and Perspective 511 References 512 19 Polymer Brushes andMicroorganisms 515Madeleine Ramstedt 19.1 Introduction 515 19.1.1 Societal Relevance for Surfaces Interacting with Microbes 515 19.1.2 Microorganisms 516 19.2 Brushes and Microbes 519 19.2.1 Adhesive Surfaces 529 19.2.2 Antifouling Surfaces 530 19.2.2.1 PEG-Based Brushes 531 19.2.2.2 Zwitterionic Brushes 533 19.2.2.3 Brush Density 533 19.2.2.4 Interactive Forces 535 19.2.2.5 Mechanical Interactions 537 19.2.3 Killing Surfaces 537 19.2.3.1 Antimicrobial Peptides 540 19.2.4 Brushes and Fungi 543 19.2.5 Brushes and Algae 546 19.3 Conclusions and Future Perspectives 549 Acknowledgments 551 References 552 20 Design of Polymer Brushes for Cell Culture and Cellular Delivery 557Danyang Li and Julien E. Gautrot Abbreviations 557 20.1 Introduction 559 20.2 Protein-Resistant Polymer Brushes for Tissue Engineering and In Vitro Assays 561 20.2.1 Design of Protein-Resistant Polymer Brushes 561 20.2.2 Cell-Resistant Polymer Brushes 565 20.2.3 Patterned Antifouling Brushes for the Development of Cell-Based Assays 567 20.3 Designing Brush Chemistry to Control Cell Adhesion and Proliferation 570 20.3.1 Polyelectrolyte Brushes for Cell Adhesion and Culture 570 20.3.2 Control of Surface Hydrophilicity 573 20.3.3 Surfaces with Controlled Stereochemistry 574 20.3.4 Switchable Brushes Displaying Responsive Behavior for Cell Harvesting and Detachment 576 20.4 Biofunctionalized Polymer Brushes to Regulate Cell Phenotype 581 20.4.1 Protein Coupling to Polymer Brushes to Control Cell Adhesion 581 20.4.2 Peptide-Functionalized Polymer Brushes to Regulate Cell Adhesion, Proliferation, Differentiation, and Migration 583 20.5 Polymer Brushes for Drug and Gene Delivery Applications 586 20.5.1 Polymer Brushes in Drug Delivery 586 20.5.2 Polymer Brushes in Gene Delivery 590 20.6 Summary 593 Acknowledgments 593 References 593 21 DNA Brushes: Self-Assembly, Physicochemical Properties, and Applications 605Ursula Koniges, Sade Ruffin, and Rastislav Levicky 21.1 Introduction 605 21.2 Applications 605 21.3 Preparation 607 21.4 Physicochemical Properties of DNA Brushes 610 21.5 Hybridization in DNA Brushes 613 21.6 Other Bioprocesses in DNA Brushes 618 21.7 Perspective 619 Acknowledgments 620 References 621 22 DNA Brushes: Advances in Synthesis and Applications 627Renpeng Gu, Lei Tang, Isao Aritome, and Stefan Zauscher 22.1 Introduction 627 22.2 Synthesis of DNA Brushes 628 22.2.1 Grafting-to Approaches 628 22.2.1.1 Immobilization on Gold Thin Films 628 22.2.1.2 Immobilization on Silicon-Based Substrates 632 22.2.2 Grafting-from Approaches 634 22.2.2.1 Surface-Initiated Enzymatic Polymerization 634 22.2.2.2 Surface-Initiated Rolling Circle Amplification 634 22.2.2.3 Surface-Initiated Hybridization Chain Reaction 634 22.2.3 Synthesis of DNA Brushes on Curved Surfaces 637 22.3 Properties and Applications of DNA Brushes 637 22.3.1 The Effect of DNA-Modifying Enzymes on the DNA Brush Structure 637 22.3.2 Stimulus-Responsive Conformational Changes of DNA Brushes 639 22.3.3 DNA Brush for Cell-Free Surface Protein Expression 643 22.3.4 DNA Brush-Modified Nanoparticles for Biomedical Applications 645 22.4 Conclusion and Outlook 649 References 649 23 Membrane Materials Form Polymer Brush Nanoparticles 655Erica Green, Emily Fullwood, Julieann Selden, and Ilya Zharov 23.1 Introduction 655 23.2 Colloidal Membranes Pore-Filled with Polymer Brushes 657 23.2.1 Preparation of Silica Colloidal Membranes 657 23.2.2 PAAM Brush-Filled Silica Colloidal Membranes 658 23.2.3 PDMAEMA Brush-Filled Silica Colloidal Membranes 659 23.2.4 PNIPAAM brush-filled silica colloidal membranes 664 23.2.5 Polyalanine Brush-Filled Silica Colloidal Membranes 666 23.2.6 PMMA Brush-Filled SiO2@Au Colloidal Membranes 670 23.2.7 Colloidal Membranes Filled with Polymers Brushes Carrying Chiral Groups 672 23.2.8 pSPM and pSSA Brush-Filled Colloidal Nanopores 673 23.3 Self-Assembled PBNPs Membranes 676 23.3.1 PDMAEMA/PSPM Membranes 676 23.3.2 PHEMA Membranes 678 23.3.3 pSPM and pSSA Membranes 680 23.4 Summary 683 References 683 24 Responsive Polymer Networks and Brushes for Active Plasmonics 687Nestor Gisbert Quilis, Nityanand Sharma, Stefan Fossati,Wolfgang Knoll, and Jakub Dostalek 24.1 Introduction 687 24.2 Tuning Spectrum of Surface Plasmon Modes 688 24.3 Polymers Used for Actuating of Plasmonic Structures 692 24.3.1 Temperature-Responsive Polymers 692 24.3.2 Optical Stimulus 694 24.3.3 Electrochemical Stimulus 695 24.3.4 Chemical Stimulus 696 24.4 Imprinted Thermoresponsive Hydrogel Nanopillars 697 24.5 Thermoresponsive Hydrogel Nanogratings Fabricated by UV Laser Interference Lithography 699 24.6 Electrochemically Responsive Hydrogel Microgratings Prepared by UV Photolithography 702 24.7 Conclusions 705 Acknowledgments 706 References 706 25 Polymer Brushes as Interfacial Materials for Soft Metal Conductors and Electronics 709Casey Yan and Zijian Zheng 25.1 Introduction 709 25.2 Mechanisms of Polymer-Assisted Metal Deposition 712 25.3 Role of Polymer Brushes 716 25.4 Selection Criterion of Polymer Brushes Enabling PAMD 716 25.5 Strategies to Fabricate Patterned Metal Conductors 717 25.6 PAMD on Different Substrates and Their Applications in Soft Electronics 720 25.6.1 On Textiles 720 25.6.2 On Plastic Thin films 721 25.6.3 On Elastomers 724 25.6.4 On Sponges 728 25.7 Conclusion, Prospects, and Challenges 731 References 732 26 Nanoarchitectonic Design of Complex Materials Using Polymer Brushes as Structural and Functional Units 735M. Lorena Cortez, Gisela Dyaz,Waldemar A. Marmisolle, Juan M. Giussi, and Omar Azzaroni 26.1 Introduction 735 26.2 Nanoparticles at Spherical Polymer Brushes: Hierarchical Nanoarchitectonic Construction of Complex Functional Materials 736 26.3 Nanotube and Nanowire Forests Bearing Polymer Brushes 737 26.3.1 Polymer Brushes on Surfaces DisplayingMicrotopographical Hierarchical Arrays 738 26.3.2 Environmentally Responsive Electrospun Nanofibers 740 26.4 Fabrication of Free-Standing "Soft" Micro- and Nanoobjects Using Polymer Brushes 741 26.5 Solid-State Polymer Electrolytes Based on Polymer Brush-Modified Colloidal Crystals 743 26.6 Proton-Conducting Membranes with Enhanced Properties Using Polymer Brushes 745 26.7 Hybrid Architectures Combining Mesoporous Materials and Responsive Polymer Brushes: Gated Molecular Transport Systems and Controlled Delivery Vehicles 747 26.8 Ensembles of Metal NanoparticlesModified with Polymer Brushes 750 26.9 Conclusions 754 Acknowledgments 755 References 755 Index 759