Nanostructured Soft Matter (eBook)

Preface 6
Contents 8
List of Contributors 11
Part I Experimental Advances 13
Microemulsion Templating 15
1 Introduction 15
2 The Microemulsion Template 18
3 Precipitation of (Inorganic) Nanoparticles in Droplet Phases 39
4 (Micro)Emulsion Polymerisation 46
5 Templating of Crystalline Phases 51
References 54
Nanofabrication of Block Copolymer Bulk and Thin Films 57
Microdomain Structures as Templates 57
1 Introduction and Background 57
2 Bulk Block Copolymers 61
3 Thin Film Block Copolymer 82
References 106
Characterization of Surfactant Water Systems by X-Ray Scattering and NMR 111
1 Introduction to Surfactant Water Systems 111
2 Small Angle X-Ray Scattering (SAXS) 113
3 Scattering from Surfactant Water Systems 116
4 2H NMR 128
5 2H NMR from Surfactant Water Systems 130
6 Outlook 138
References 139
Polyelectrolyte Diblock Copolymer Micelles 141
1 Introduction 141
2 Small Angle Neutron and X-Ray Scattering 143
3 Corona Chain Statistics 146
4 Polyelectrolyte Block Ionization 150
5 Association Morphology 151
6 Core Structure 152
7 Counterion Structure 154
8 Corona Structure 156
9 Inter-Micelle Structure 162
10 Visco-Elastic Behavior 167
11 Conclusions and Outlook 168
References 169
Structure and Shear-Induced Order in Blends of a Diblock Copolymer with the Corresponding Homopolymers 171
1 Introduction 171
2 Experimental 172
3 Results 174
4 Summary 181
References 182
Electric Field Alignment of Diblock Copolymer Thin Films 183
1 Introduction 183
2 Interfacial Interactions: Asymmetric Diblock Copolymers 184
3 Interfacial Interactions: Symmetric Diblock Copolymers 188
4 Interfacial Interactions: Asymmetric Diblock Copolymers 191
5 Electric Field Alignment: Symmetric Diblock Copolymers 192
6 Electric Field Alignment: Asymmetric Diblock Copolymers 194
7 Electric Field Induced Sphere-to-Cylinder Transition 199
8 Influence of Free Ions 201
9 Sequential, Orthogonal Fields 205
10 Summary 208
References 208
Structure and Dynamics of Cylinder Forming Block Copolymers in Thin Films 243
1 Introduction 243
2 Surface Structures in Thin Films of Cylinder Forming Block Copolymers 249
3 Characteristic Dimensions of the Microdomain Structures 261
4 Dynamics 265
5 Control of Nanostructure in Block Copolymer Thin Films: Long-Term Prospects 270
References 271
Part II Mathematical and Theoretical Approaches 279
Scaling Theory of Polyelectrolyte and Polyampholyte Micelles 312
1 Introduction 312
2 Scaling Description of Polyelectrolyte Chains 315
3 Polyelectrolyte Stars 316
4 Polyelectrolyte Micelles 320
5 Polyampholyte Micelles 325
6 Summary and Potential Applications 332
7 Perspectives 334
References 335
The Latest Development of the Weak Segregation Theory of Microphase Separation in Block Copolymers 339
1 Introduction 339
2 The WST and the Non-Conventional Phases’ Stability 352
3 WST Applications to Multi-Component Block Copolymer Systems 361
4 The WST Predicted Peculiarities in the Multi-Component Block Copolymer Systems 365
Appendix A. The Basic Weakly Segregated Morphologies 375
References 379
Coarse-Grained Modeling of Mesophase Dynamics in Block Copolymers 383
1 Introduction 383
2 Mesoscopic Modeling 384
3 Defected Structure and Dynamics 387
4 Control: Shear Alignment 393
5 Perspectives 403
References 404
Effective Interactions in Soft Materials 407
1 Introduction 407
2 Systems of Interest 408
3 E.ective Interaction Methods 410
4 Applications 425
5 Summary and Outlook 442
References 443
Part III Computer Simulations 447
Ab-initio Coarse-Graining of Entangled Polymer Systems 449
1 Introduction 449
2 Theory 452
3 Coarse-Graining in Practice 458
4 Twentanglement 461
5 Application 1: Polyethylene Melts 464
6 Application 2: Wormlike Micelles 467
7 Conclusion 470
References 472
Computer Simulations of Nano-Scale Phenomena Based on the Dynamic Density Functional Theories Applications of SUSHI in the OCTA System 473
1 Introduction 473
2 Gaussian Chain Model 475
3 An Overview of the SCF Theory and GRPA 478
4 SCF Theory 479
5 A DFT for General Polymer Structures Using RPA 496
6 Perspectives 500
Appendices 501
A. Subchain Scattering Function by the RPA 501
B. Scattering Functions from an Ideal Gaussian Chain 503
References 504
Monte Carlo Simulations of Nano-Confined Block Copolymers 507
1 Introduction 507
2 Lattice Models 508
3 Diblock Copolymer Thin Films 510
4 Triblock Copolymer Thin Films 527
5 Nano-Con.nement in Two and Three Dimensions 531
6 Perspectives 534
References 536
Understanding Vesicles and Bio-Inspired Systems with Dissipative Particle Dynamics 541
1 Introduction 541
2 Computational Membrane Models 546
3 Simulations of Soft Biomaterials 554
4 Perspectives 562
References 563
Theoretical Study of Nanostructured Biopolymers Using Molecular Dynamics Simulations 567
1 Introduction 567
2 Force Fields 569
3 Cutting the Energy Off 573
4 Atomic Starting Positions 574
5 Chiare, Fresche et Dolci Acque . . . [28] 575
6 Fiat Vis! 575
7 Keeping Molecules Warm and Under Pressure 576
8 Starting the Simulation 577
9 Advanced MD Methods 577
10 Molecular Modeling Programs 580
11 Analysis of the Simulation Trajectory 581
12 Perspectives 593
References 595
Understanding Liquid/Colloids Composites with Mesoscopic Simulations 598
1 Introduction 598
2 Kinetic Approaches: Lattice Boltzmann 601
3 Non-Ideal Fluids: A Binary Mixture 604
4 Colloidal Suspensions 607
5 Mesoscopic Particle-Based Methods: E.ective Interactions 618
6 Conclusions 623
References 623
Index 627

Scaling Theory of Polyelectrolyte and Polyampholyte Micelles (S. 300-301)

Nadezhda P. Shusharina and Michael Rubinstein

Department of Chemistry, University of North Carolina, Chapel Hill, North Carolina 27599-3290, USA

1 Introduction

Polymer solutions have been extensively studied for the past three decades [1–3]. Owing to the successful application of scaling theory [1] the solution properties of uncharged polymers are now reasonably well understood. However, many practically important polymers, both synthetic and natural, are charged in polar solvents, most commonly in water. The added complexity of charged systems stems from their long-range electrostatic interactions. The additional emerging length scales make the scaling approach to charged systems much more challenging than for neutral ones. At the same time, research into the functional materials, drug delivery formulations and stabilization of colloidal systems has led to the development of new types of polyelectrolytes, including charged polymeric surfactants. Study of these new polymers is of great industrial importance and provides an excellent opportunity for the introduction and validation of theoretical approaches. Therefore the theory of solutions of charged polymers remains a quickly developing area of polymer physics and material science [4–6].

In contrast to low-molecular weight compounds, polymers have a very important structural degree of freedom called molecular architecture. Speci.- cally, linear polymer chains can be linked together in di.erent fashions forming a single macromolecule. The control of molecular architecture is a widely used approach in the development of polymers with desired properties [7]. The simplest examples of the chain arrangement are block copolymers, where chemically di.erent chains are linked together end to end, and polymer stars, where several chains are linked at one point. The conformations of polymer subchains in a branched molecule depend on its architecture. For example, the interaction of monomers in a star is stronger than in a linear chain because of the additional interactions between the monomers belonging to di.erent chains (arms). If, for example, the monomers along the chain repel each other, the arms in a star will be more extended than the equivalent linear chains [8]. The structure of polyelectrolyte stars is even more complex [9]. An accumulation of a large charge in a small volume of the star leads to a non-uniform distribution of counterions in solution. The non-uniformity is due to an interplay of the electrostatic energy of the star and the entropy of the counterions.

To lower the electrostatic energy, counterions tend to be con.ned within the volume of the star. However, complete con.nement (condensation) of counterions would lead to a signi.cant loss of their entropy, so the minimum of the free energy is achieved when a fraction of counterions resides within the star, while the remaining counterions are spread throughout the surrounding solution [10,11]. The uncompensated charge of the star leads to a larger extension of the star arms as compared to neutral stars. Moreover, this extension is not uniform because of the existence of two characteristic regions in the star. In the center the concentration of monomers is so high that the short-range monomer-monomer interactions are stronger than the electrostatic long-range interactions. Hence, in the center the extension is the same as in a neutral star. In the outer region the electrostatics dominate, making the extension much larger than that in the corresponding part of a neutral star.