What do bird flocks, bacterial swarms, cell tissues, and cytoskeletal fluids have in common? They are all examples of active matter. This book explores how scientists in various disciplines, from physics to biology, have collated a solid corpus of experimental designs and theories during the last two decades to decipher active systems.
The book addresses, from a multidisciplinary viewpoint, the field of active matter at a colloidal scale. Concepts, experiments, and theoretical models are put side by side to fully illuminate the subtilities of active systems. A large variety of subjects, from microswimmers or driven colloids to self-organized active fluids, are analysed within a unified perspective. Generic collective effects of self-propelled or driven colloids, such as motility-induced flocking, and new paradigms, such as the celebrated concept of active nematics in reconstituted protein-based fluids, are discussed using well-known experimental scenarios and recognized theories. Topics are covered with rigor and in a self-consistent way, reaching both practitioners and newcomers to the field.
The diversity of topics and conceptual challenges in active matter have long hampered the chance to explore the field with a general perspective. This monograph, the first single-authored title on active matter, is intended to fill this gap by bridging disparate experimental and theoretical interests from colloidal soft matter to cell biophysics.
Author(s): Francesc Sagués Mestre
Series: Advances in Biochemistry and Biophysics
Publisher: CRC Press
Year: 2022
Language: English
Pages: 307
City: Boca Raton
Cover
Half Title
Series Page
Title Page
Copyright Page
Dedication
Contents
Preface
List of Figures
Symbols
1. Introduction
2. Fundamental Concepts: Isotropic and Anisotropic Colloidal Suspensions
2.1. Isotropic Dilute Suspensions
2.1.1. Microscopic Colloidal Behavior: Diffusion, Sedimentation and Random Walk Models
2.1.2. The Boundary Layer Concept: Electrically Charged Interfaces
2.1.3. Effects of Polymers on Colloidal Stability
2.2. Anisotropic Dense Suspensions: Colloidal Liquid Crystals
2.2.1. The Role of Colloid Shape and Concentration
2.2.2. Basic Concepts of Liquid Crystals: Phases and Order Parameter
2.2.3. Long- and Short-Range Order: Orientational Distortions and Defects
2.3. A Composite System: Nematic Colloids
3. Particle-based Active Systems
3.1. Self-propelled Swimmers
3.1.1. Self-phoretic Swimmers and their Active Brownian Particle (ABP) Models
3.1.1.1. General Concepts
3.1.1.2. Experimental Realizations of Phoretic Swimmers
3.1.1.3. Basic Statistical Properties of Self-phoretic Swimmers: Diffusion and Sedimentation
3.1.1.4. The Active Brownian Model
3.1.2. Swimmers Based on Marangoni Flows
3.1.3. Biological Microswimmers
3.1.3.1. Flagellated Bacteria
3.1.3.2. Other Biological Microswimmers
3.2. Colloids Driven to Swim
3.2.1. Magnetic Forcing
3.2.1.1. A Doublet Roller
3.2.1.2. A Magnetically Driven Magnetic Snake
3.2.1.3. Magnetic Spinners
3.2.2. Electric Forcing: Quincke Rollers under DC Driving
3.2.3. Electric Forcing: Classical Fixed-Charge Electroosmotic Flows
3.2.4. Induced-Charge Electrophoresis under AC Driving
3.2.4.1. Induced-Charge Electrophoresis
3.2.4.2. Liquid Crystal-Enabled Electrophoresis
3.2.4.3. Anomalous Statistical Characteristics of Driven Nematic Colloids
3.3. Brief Commented List of Selected Review Papers
4. Protein-based Active Fluids
4.1. Active Gels Based on Filamentary Proteins
4.1.1. Active Gels Based on Actin Filaments
4.1.2. Active Gels Based on Microtubules
4.1.2.1. Historic Antecedents
4.1.2.2. The Brandeis Approach
4.2. Two-dimensional Active Nematics
4.2.1. Active Nematics Based on Microtubules
4.2.2. Active Nematics Based on Actin Filaments
4.3. The Effect of the Interface on Two-Dimensional Active Nematics
4.3.1. Aqueous Active Nematics Interfaced with Isotropic Oils
4.3.2. Aqueous Active Nematics Interfaced with Anisotropic Oils
4.4. Effects of Spatial Confinement
4.4.1. Encapsulated Active Nematics
4.4.2. Geometric Confinement of Active Nematics
4.4.3. A New Concept: Active Boundary Layers
4.4.4. Geometric Confinement of Active Gels
4.5. Recent Advances in the Preparation of Active Gels and Active Nematics
5. Emerging Concepts in Active Matter
5.1. Dynamic Clustering and Swarming Behavior
5.1.1. Experimental Observations of Dynamic Clustering
5.1.2. Modeling Approaches to Clustering of Microswimmers
5.2. Motility-Induced Phase Separation
5.3. Active Turbulence
5.4. Thermodynamic Concepts in Active Matter
5.4.1. Active Temperature
5.4.2. Active Pressure
6. Modeling Active Fluids
6.1. Linearized Leslie-Ericksen Theories for Active Polar Fluids
6.1.1. General Scheme of Equations
6.1.2. Analysis of +1 Defects: Asters, Vortices, and Spirals
6.1.3. Activity-Induced Flows from Aligned States
6.1.4. Minimal Version for a Two-Dimensional Active Nematic in Absence of Flow-Alignment
6.2. A Beris-Edwards Approach to Model Active Nematics
6.2.1. General Scheme of Equations
6.2.2. A Simplified Analysis of Defect Dynamics
6.2.3. Theoretical Description of Active Nematic Turbulence
6.3. Modeling Interfaced Active Fluids
6.4. Modeling Confined Active Fluids
6.4.1. Modeling Active Flows in Thin Films and Droplets
6.4.1.1. Thin Active Films
6.4.1.2. Active Droplets
6.4.2. Modeling Active Flows under Geometric Confinement
6.5. Brief Commented List of Selected Review Papers
7. Concepts and Models for Dry Active Matter
7.1. Hydrodynamic-like Theories
7.1.1. Flocking of Active Polar Particles
7.1.1.1. Giant Number Fluctuations
7.1.2. Particles Interacting Nematically on a Substrate
7.1.3. Self-Propelled Rods with Nematic Alignment
7.2. Microscopic-like Theories
7.2.1. Particle-Based Models for Dry Systems
7.2.2. Common Rationale: Phase-Separated Regimes
7.2.3. Specific Class-Dependent Features
7.2.3.1. Traveling Bands in Polar Class
7.2.3.2. Unstable Nematic Bands
7.2.4. Properties of the Liquid Ordered Phase
8. Appendix 1: Microswimming in Constrained and Disordered Environments
8.1. Microswimming under Constrained Motion
8.2. Microswimming under the Effects of Noise and Disorder
9. Appendix 2: Microswimming in Complex Fluids
9.1. Motion of Microorganisms in Complex Fluids
9.2. Artificial Microswimmers Performing in Complex Fluids
9.3. Theoretical Approaches to Microswimming in Complex Fluids
10. Appendix 3: Motility Assays
10.1. Motility Assays Based on the Actin System
10.2. Motility Assays Based on the Tubulin System
11. Appendix 4: Active Nematic Concepts in the Context of Cell Tissues
11.1. Textures, Flows, and Defects in Cell Tissues
Bibliography
Index
