Dynamics and Transport in Macromolecular Networks: Theory, Modelling, and Experiments

Dynamics and Transport in Macromolecular Networks Comprehensive knowledge on concepts and experimental advancement, as well as state-of-the-art computational tools and techniques for simulation and theory Dynamics and Transport in Macromolecular Networks: Theory, Modeling, and Experiments provides a unique introduction to the currently emerging, highly interdisciplinary field of those transport processes that exhibit various dynamic patterns and even anomalous behaviors of dynamics, investigating concepts and experimental advancement, as well as state-of-the-art computational tools and techniques for the simulation of macromolecular networks and the transport behavior in them. The detailed text begins with discussions on the structural organization of various macromolecular networks, then moves on to review and consolidate the latest research advances and state-of-the-art tools and techniques for the experimental and theoretical studies of the transport in macromolecular networks. In so doing, the text extracts and emphasizes common principles and research advancement from many different disciplines while providing up-to-date coverage of this new field of research. Written by highly experienced and internationally renowned specialists in various disciplines, such as polymer, soft matter, chemistry, biophysics, and more, Dynamics and Transport in Macromolecular Networks covers sample topics such as: Modeling (visco)elasticity macromolecular and biomacromolecular networks, covering statistical and elastic models and permanent biomacromolecular networks Focus on controlled degradation in modeling reactive hydrogels, covering mesoscale modeling of reactive polymer networks and modeling crosslinking due to hydrosilylation reaction Dynamic bonds in associating polymer networks, covering segmental and chain dynamics and phase-separated aggregate dynamics Direct observation of polymer reptation in entangled solutions and junction fluctuations in crosslinked networks, covering tube width fluctuations and dynamic fluctuations of crosslinks A much-needed overview of developments and scientific findings in the transport behaviors in macromolecular networks, Dynamics and Transport in Macromolecular Networks is a highly valuable resource for chemists, physicists, and other scientists and engineers working in fields related to macromolecular network systems, both theoretically and experimentally.

Table of Contents:
Preface xi 1 Modeling (Visco)elasticity of Macromolecular and Biomacromolecular Networks 1 Fanlong Meng 1.1 Permanent Macromolecular Networks 2 1.1.1 Mechanic Properties of a Single Polymer Chain 2 1.1.2 Statistical Models 3 1.1.3 Phenomenological Models 6 1.2 Permanent Biomacromolecular Networks 7 1.2.1 Elastic Models 8 1.2.2 Nonlinear Elasticity, Stability, and Normal Stress 9 1.3 Transient Macromolecular/Biomacromolecular Networks 12 1.3.1 Theoretical Framework 13 1.3.2 Applications 14 1.4 Outlooks 19 References 19 2 Modeling Reactive Hydrogels: Focus on Controlled Degradation 25 Vaibhav Palkar and Olga Kuksenok 2.1 Introduction 25 2.2 Mesoscale Modeling of Reactive Polymer Networks 26 2.2.1 Introducing Dissipative Particle Dynamics Approach for Reactive Polymer Networks 26 2.2.2 Addressing Unphysical Crossing of Polymer Bonds in DPD Along with Reactions 28 2.2.3 Modeling Cross-linking Due to Hydrosilylation Reaction 29 2.2.4 Mesoscale Modeling of Degradation and Erosion 32 2.3 Continuum Modeling of Reactive Hydrogels 39 2.3.1 Modeling Chemo- and Photo-Responsive Reactive Hydrogels 39 2.3.2 Continuum Modeling of Degradation of Polymer Network 40 2.4 Conclusions 42 Acknowledgments 43 References 43 3 Dynamic Bonds in Associating Polymer Networks 53 Jiayao Chen, Xiao Zhao, and Peng-Fei Cao 3.1 Introduction of Dynamic Bonds 53 3.1.1 Dynamic Covalent Bonds 53 3.1.2 Dynamic Noncovalent Bonds 55 3.2 Physical Insight of Dynamic Bonds 57 3.2.1 Segmental and Chain Dynamics 57 3.2.2 Phase-Separated Aggregate Dynamics 60 3.3 Properties and Applications 65 3.3.1 Gas Separation 66 3.3.2 Adhesives and Additives 70 3.3.3 3D Printing 73 3.3.4 Polymer Electrolytes 74 3.4 Conclusion 78 References 78 4 Direct Observation of Polymer Reptation in Entangled Solutions and Junction Fluctuations in Cross-linked Networks 83 Fengxiang Zhou and Lingxiang Jiang 4.1 Introduction 83 4.2 Reptation in Entangled Solutions 84 4.2.1 Direct Confirmation of the Reptation Model 86 4.2.2 Tube Width Fluctuations 88 4.2.3 Dependence of Tube Width on Chain Position 89 4.2.4 Tube Width under Shear 89 4.2.5 Interactions Between Reptating Polymer Chains 90 4.3 Dynamic Fluctuations of Cross-links 92 4.3.1 Dynamics Probed by Neutron Scattering 93 4.3.2 Dynamics Probed by Direct Imaging 94 4.4 Conclusion 98 Acknowledgments 98 Conflict of Interest 98 References 98 5 Recent Progress of Hydrogels in Fabrication of Meniscus Scaffolds 101 Chuanchuan Fan, Ziyang Xu, and Wenguang Liu 5.1 Introduction 101 5.2 Microstructure and Mechanical Properties of Meniscus 102 5.2.1 Meniscus Anatomy, Biochemical Content, and Cells 102 5.2.2 Biomechanical Properties of the Meniscus 104 5.3 Biomaterial Requirements for Constructing Meniscal Scaffolds 105 5.4 Hydrogel-Based Meniscus Scaffolds 106 5.4.1 Providing Matrix for Cell Growth and Biomacromolecules Delivery 106 5.4.1.1 Injectable Hydrogel-Based Meniscus Tissue-Engineering Scaffolds 107 5.4.1.2 High Strength and Biodegradable Hydrogel-Based Meniscus Scaffolds 109 5.4.1.3 3D-Printed Polymer/Hydrogel Composite Tissue-Engineering Scaffolds 109 5.4.2 Providing Load-Bearing Capability 114 5.4.2.1 Polyvinyl Alcohol (PVA) Hydrogel-Based Meniscus Scaffolds 115 5.4.2.2 Poly(N-acryloyl glycinamide) (PNAGA) Hydrogel-Based Meniscus Scaffolds 117 5.4.2.3 Poly(N-acryloylsemicarbazide) (PNASC) Hydrogel-Based Meniscus Scaffold 119 5.4.2.4 Other Systems 120 5.5 Mimicking Microstructure: The Key to Constructing the Next-Generation Meniscus Scaffolds 122 5.6 Conclusion 123 References 124 6 Strong, Tough, and Fast-Recovery Hydrogels 133 BinXueandYiCao 6.1 Current Progress on Strong and Tough Hydrogels 133 6.2 Polymer-Supramolecular Double-Network Hydrogels 136 6.3 Hybrid Networks with Peptide-Metal Complexes 137 6.4 Hydrogels Cross-Linked with Hierarchically Assembled Peptide Structures 139 6.5 Outlook 140 References 141 7 Diffusio-Mechanical Theory of Polymer Network Swelling 149 Zhaoyu Ding, Peihan Lyu, and Xingkun Man 7.1 Introduction 149 7.2 Swelling Model 153 7.2.1 General Theoretical Framework 156 7.2.1.1 Spherical Gel 156 7.2.1.2 Cylindrical Gel 157 7.2.1.3 Disk-Shaped Gel 157 7.2.2 Diffusio-Mechanical Model for Small Deformation 158 7.2.2.1 Spherical Gel 158 7.2.2.2 Cylindrical Gel 162 7.2.2.3 Disk-Shaped Gel 164 7.3 Results 166 7.4 Perspective 169 7.5 Conclusion 171 Acknowledgments 172 References 172 8 Theoretical and Computational Perspective on Hopping Diffusion of Nanoparticles in Cross-linked Polymer Networks 175 Ting Ge 8.1 Introduction 175 8.2 2010s’ Theories of Nanoparticle Hopping Diffusion 176 8.2.1 Scaling Theory by Cai, Paniukov, and Rubinstein 176 8.2.1.1 Confinement by Network as Attachment to Virtual Chains 177 8.2.1.2 Hopping Diffusion as Successive Individual Hopping Events 178 8.2.1.3 Beyond Homogeneous, Entanglement-Free, and Dry Cross-linked Networks 180 8.2.2 Microscopic Theory by Dell and Schweizer 182 8.3 Recent Computational and Theoretical Work 183 8.3.1 Evaluating Cai–Paniukov–Rubinstein and Dell–Schweizer Theories by Simulations 183 8.3.2 Exploring New Aspects of Cross-linked Networks – Stiffness and Geometry 185 8.4 Open Questions and Future Research Directions 189 8.4.1 Network Strands with Nonlinear Architectures 189 8.4.2 Sticky and Polymer-Tethered Nanoparticles 191 8.4.3 Nanoparticles with Anisotropic Shape 191 8.4.4 Active Nanoparticles – Nonequilibrium Effects 192 8.5 Concluding Remarks 193 Acknowledgments 193 References 194 9 Molecular Dynamics Simulations of the Network Strand Dynamics and Nanoparticle Diffusion in Elastomers 199 Yulong Chen and Jun Liu 9.1 Introduction 199 9.2 Structures and Dynamics of Model Elastomer Networks 200 9.2.1 Randomly Cross-linked Elastomer Networks 200 9.2.1.1 Network Models and Simulation Methodology 201 9.2.1.2 Network Topology 202 9.2.1.3 Effect of Cross-link Density on Network Dynamics 204 9.2.1.4 Effect of Cross-link Distribution on Network Dynamics 206 9.2.1.5 Effect of Temperature on Network Dynamics 208 9.2.2 End-linked Elastomer Networks 210 9.2.2.1 Network Models and Simulation Methodology 210 9.2.2.2 Network Topology 211 9.2.2.3 Network Dynamics 212 9.3 Diffusion Dynamics of Nanoparticles in Elastomers: Melts and Networks 214 9.3.1 Diffusion of Nanoparticles in Elastomer Melts 215 9.3.1.1 Models and Simulation Methodology 215 9.3.1.2 Size Effect on Nanoparticle Diffusion 216 9.3.1.3 Effect of Surface Grating on Nanoparticle Diffusion 218 9.3.1.4 Nanoparticle Diffusion in Bottlebrush Elastomers 223 9.3.2 Diffusion of Nanoparticles in Elastomer Networks 227 9.3.2.1 Models and Simulation Methodology 227 9.3.2.2 Size Effect on Nanoparticle Diffusion 228 9.3.2.3 Nanoparticle Diffusion in Attractive Networks 232 9.4 Conclusions 236 Acknowledgments 238 References 239 10 Experimental and Theoretical Studies of Transport of Nanoparticles in Mucosal Tissues 245 Falin Tian and Xinghua Shi 10.1 Introduction 245 10.2 Enhancing Diffusivity of Deformable Particles to Overcome Mucus Barriers Via Adjusting Their Rigidity 248 10.2.1 The Preparation of the Hybrid NPs with Various Rigidities 249 10.2.2 The Diffusivity of Hybrid NPs with Different Rigidity in Mucus 250 10.2.3 The Interaction Between NPs with Different Rigidity and Mucus Network 252 10.2.4 The Theoretical Model to Describe the Diffusion Behavior of Deformable Nanoparticles in Adhesion Network 255 10.2.4.1 Shape Distribution of NPs 256 10.2.4.2 Diffusion Model 258 10.2.5 Summary 260 10.3 The Effect of the Shape on the Diffusivity of NPs in Mucus 261 10.3.1 The Diffusion Behaviors of NPs with Various Shapes in Mucus 261 10.3.2 The Diffusion Mechanisms of NPs with Different Shape in Biological Hydrogels 263 10.3.3 Theoretical Model of Diffusion of Rod-Like Nanoparticles in Polymer Networks 265 10.3.3.1 Nonadhesive Diffusion Model 265 10.3.3.2 Adhesive Diffusion Model 268 10.3.4 The Effect of the Surface Polyethylene Glycols (PEGs) Distribution on the Diffusivity of Rod-Like NPs 269 10.3.5 Summary 272 10.4 Conclusion and Outlook 272 References 274 11 Physical Attributes of Nanoparticle Transport in Macromolecular Networks: Flexibility, Topology, and Entropy 281 Xiaobin Dai, Xuanyu Zhang, Lijuan Gao, Yuming Wang, and Li-Tang Yan 11.1 Introduction 281 11.2 Effects of the Chain Flexibility of Strands 282 11.2.1 Dynamical Heterogeneity of a Semiflexible Network 283 11.2.2 Nonmonotonic Feature 284 11.2.3 Validation by MC Simulations and Experimental Data 287 11.3 Effects of Network Topology 288 11.3.1 Analytical Model for Free Energy Landscape 289 11.3.2 Network Topology and Free Energy Landscape 289 11.3.3 Topology-Dictated Scaling Regimes of Free Energy Change 291 11.3.4 Topology-Mediated Dynamical Regimes 294 11.4 Summary and Outlook 295 Acknowledgments 296 References 296 Index 299

About the Author :
Li-Tang Yan, PhD, is Professor in the Department of Chemical Engineering at Tsinghua University, China. His research interests focus on computational and theoretical aspects of soft matter systems, including macromolecular networks, nanoparticle cellular interactions and entropy-controlled strategy in equilibrium and nonequilibrium systems.