Cover -- Title Page -- Copyright -- Contents -- Preface -- Part I Materials -- Chapter 1 Extreme Mechanics of Hydrogels Toward In Situ Hydrogel Bioelectronics -- 1.1 Introduction -- 1.2 Extreme Properties of Hydrogels by Polymer Network Design -- 1.2.1 Elastic Modulus -- 1.2.2 Fracture Toughness -- 1.2.3 Fatigue Threshold -- 1.2.4 Mass Transport -- 1.3 Stretchable Hydrogel Conductors -- 1.3.1 Multiscale Orthogonal Design -- 1.3.2 Implementations of the Orthogonal Design -- 1.4 Electrochemical Hydrogel Biosensors -- 1.4.1 Selective Transport Design of Hydrogels -- 1.4.2 Electrochemical Design of Hydrogel-2D Material Interfaces -- 1.5 Flexible Hydrogel Biobattery -- 1.5.1 Mechanical Energy Harvester -- 1.5.2 Chemical Energy Harvesters -- 1.5.3 Thermal Energy Harvesters -- 1.6 Concluding Remarks -- Acknowledgments -- References -- Chapter 2 Multiscale Mechanics of Metal Nanowire-Based Stretchable Electronics -- 2.1 Introduction -- 2.2 Metal NW-Based Flexible and Stretchable Electronics -- 2.3 Mechanics of Individual NWs -- 2.3.1 Overview of Mechanics of Metal NWs -- 2.3.2 Mechanics of Single-Crystalline Metal NWs -- 2.3.3 Mechanics of Bi-Twinned Metal NWs -- 2.3.4 Mechanics of Penta-Twinned Metal NWs -- 2.4 Interfacial Mechanics of the NW-Polymer Interface -- 2.4.1 Classic Theory of Shear-Lag Analysis -- 2.4.2 Shear-Lag Analysis Considering Bonding Mechanisms -- 2.4.3 Fracture of NWs Due to Shear Stress Transfer -- 2.4.4 Elastoplastic Analysis of Metal NWs -- 2.5 Mechanical Design of Stretchable Structures -- 2.5.1 Buckle-Delamination Enabled Stretchable Silver Nanowire Conductors -- 2.5.2 A Highly Sensitive, Stretchable, and Robust Strain Sensor Based on Crack Advancing and Opening -- 2.6 Concluding Remarks -- Acknowledgments -- References -- Chapter 3 Liquid Metal-Based Electronics -- 3.1 Introduction -- 3.1.1 Ga-Based Liquid Metals.

3.1.2 Relevant Literature -- 3.2 LM Architectures -- 3.2.1 Microfluidic LM Channels -- 3.2.1.1 Printing-Based Deposition Methods -- 3.2.1.2 Direct LM Casting -- 3.2.2 LM-Coated Thin-Film Metal Traces -- 3.2.3 LM-Polymer Composites -- 3.2.4 Printable LM-Based Inks -- 3.3 Mechanics and Modeling -- 3.3.1 Microfluidic LM Strain Gauge -- 3.3.2 Microfluidic LM Pressure Sensor -- 3.3.3 LM-Polymer Composites -- 3.3.3.1 Electrical Permittivity and Thermal Conductivity -- 3.3.3.2 Electromechanical Coupling -- 3.3.3.3 Effective Young's Modulus -- 3.4 Open Challenges and Future Directions -- References -- Chapter 4 Mechanics of Two-Dimensional Materials -- 4.1 Introduction -- 4.2 Nanoindentation Method -- 4.3 AFM-Enabled Nanoindentation -- 4.3.1 Setup of AFM-Enabled Nanoindentation -- 4.3.2 Mechanical Testing of 2D Materials -- 4.3.2.1 Mechanical Testing of Graphene -- 4.3.2.2 Mechanical Testing of Graphene Oxide (GO) -- 4.3.2.3 Mechanical Testing of MoS2 -- 4.3.2.4 Mechanical Testing of WSe2 -- 4.3.2.5 Mechanical Testing of h-BN -- 4.3.2.6 Mechanical Testing of Black Phosphor (BP) -- 4.4 In Situ Indentation in SEM -- 4.4.1 Raman Spectroscopy -- 4.5 Micro-/Nano-mechanical Devices -- 4.5.1 Category of Micromechanical Devices -- 4.5.1.1 Thermal Actuated Micromechanical Devices -- 4.5.1.2 Micromechanical Devices with Push-Pull Mechanism -- 4.5.2 Development of the "Dry-Transfer" Technique -- 4.5.3 Mechanical Testing of 2D Materials -- 4.5.3.1 Mechanical Testing of Graphene -- 4.5.3.2 Mechanical Testing of Rebar Graphene -- 4.5.3.3 Mechanical Testing of MoSe2 -- 4.5.3.4 Mechanical Testing of h-BN -- 4.6 Piezoelectric Tube-Driven Testing in TEM -- 4.7 Bulge Testing -- 4.7.1 Depressurize Inside and Form a Concave Deflection in Film -- 4.7.2 Depressurize Outside and Form a Convex Deflection in Film -- 4.8 Electrostatic Force Triggered Drum Structure.

4.9 Phonon Dispersion Measurement -- 4.10 Summary -- 4.10.1 Mechanical Testing Techniques -- 4.10.2 Mechanical Properties of 2D Materials -- Disclosure Statement -- References -- Chapter 5 Mechanics of Flexible and Stretchable Organic Electronics -- 5.1 Introduction -- 5.2 Mechanical Characterization Methods -- 5.2.1 Tensile Tests -- 5.2.2 Fracture Toughness -- 5.2.3 Thermomechanical Behavior -- 5.3 Material Design -- 5.3.1 Molecular Weight -- 5.3.2 Backbone and Side-Chain Design -- 5.3.3 Regioregularity and Crystallinity -- 5.3.4 Block Copolymers with Flexible and Stretchable Linkers -- 5.3.5 Crosslinking and Hydrogen Bonding -- 5.3.6 Additives and Blends -- 5.3.7 Organic Photovoltaic Considerations -- 5.4 Device Design -- 5.4.1 Neutral Axis and Ultrathin Devices -- 5.4.2 Film Thickness -- 5.4.3 Electrodes and Interlayers -- 5.4.4 Interfaces -- 5.4.5 Stretchable Device Architecture -- 5.5 Applications -- 5.6 Conclusion -- Acknowledgments -- References -- Part II Design and Manufacturing -- Chapter 6 Structural Design of Flexible and Stretchable Electronics -- 6.1 Introduction -- 6.2 Design of Planar Stretchable and Flexible Structures -- 6.2.1 Wave/Wrinkle Structure Design -- 6.2.2 Island-Bridge Structure Design -- 6.2.2.1 Straight Interconnecting Island-Bridge Structure -- 6.2.2.2 Serpentine Interconnecting Island-Bridge Structure -- 6.2.2.3 Fractal-Inspired Interconnecting Island-Bridge Structure -- 6.3 Design of Three-Dimensional Flexible Electronic Structures -- 6.3.1 Helical Design -- 6.3.2 Origami-Inspired Design -- 6.3.3 Kirigami-Inspired Design -- 6.4 Design of Protective Structures for Flexible Electronic Devices -- 6.4.1 Strain Limited Structure Design -- 6.4.2 Strain Isolation Structure Design -- References -- Chapter 7 Laser-Based Fabrication Process Development for Flexible and Stretchable Electronics -- 7.1 Introduction.

7.2 Representative Laser-Based Fabrication Process -- 7.3 Applications Based on Laser Fabrication -- 7.4 Perspectives and Conclusion -- Author Contributions -- References -- Chapter 8 Electrospinning Manufacturing of Stretchable Electronics -- 8.1 Background -- 8.2 High-Precision Manufacturing -- 8.2.1 Inkjet Printing -- 8.2.2 EHD Printing -- 8.3 Electrospinning Stretchable Structure -- 8.3.1 Stretchable Nanofiber Mats -- 8.3.2 Stretchable Yarns and Fabrics -- 8.4 Application in Stretchable Electronics -- 8.4.1 Strain and Pressure Sensor -- 8.4.2 Organic Field-Effect Transistors -- 8.4.3 Optoelectronic Devices -- 8.5 Conclusions -- References -- Chapter 9 Mechanics-Guided 3D Assembly of Flexible Electronics -- 9.1 Introduction -- 9.2 Design Strategies of Mechanics-Guided Assembly -- 9.2.1 2D Precursor Designs -- 9.2.1.1 Origami/Kirigami Design Strategy -- 9.2.1.2 Multilayer and Multilevel Design Strategy -- 9.2.1.3 Design Strategy Based on Spatial Stiffness Control -- 9.2.2 Elastomer Substrate Designs -- 9.2.2.1 Engineered Planar Substrate Design Strategy -- 9.2.2.2 Curvilinear Substrate Design Strategy -- 9.2.3 Strategy of Loading Conditions -- 9.2.3.1 Mechanical Loading Strategy -- 9.2.3.2 Electric/Magnetic-Field-Assisted Loading Strategy -- 9.3 Mechanics Modeling and Analyses of the 3D Assembly -- 9.3.1 Buckling Analysis of 2D Precursors -- 9.3.1.1 Straight Ribbons -- 9.3.1.2 Helical Structures -- 9.3.1.3 Frame Structures -- 9.3.1.4 2D Curved Ribbons -- 9.3.2 Interfacial Adhesion in the Mechanics-Guided Assembly -- 9.3.2.1 Design Diagrams of Delamination States -- 9.3.2.2 Controlled Interface Delamination -- 9.3.3 Loading-Path Controlled Assembly -- 9.3.3.1 Reconfigurable Cross-Shaped Structures -- 9.3.3.2 Reconfigurable Structures Harnessing Interface Mechanics -- 9.4 Applications of 3D Flexible Electronics -- 9.4.1 Flexible Sensors.

9.4.2 Tunable Electromagnetic Devices -- 9.4.3 Biomedical Devices -- 9.4.4 Flexible Robotics -- 9.5 Concluding Remarks -- References -- Chapter 10 Harnessing Wrinkling and Buckling Instabilities for Stretchable Devices and Healthcare -- 10.1 Introduction -- 10.2 Structural Designs and Mechanics -- 10.2.1 Structural Designs for Buckling-Enabled Stretchability -- 10.2.2 Mechanics of Wrinkling and Buckling -- 10.2.2.1 Compression-Induced Wrinkling -- 10.2.2.2 Compression-Induced Constrained Buckle-Delamination -- 10.2.2.3 Compression-Induced Spontaneous Buckle-Delamination -- 10.2.2.4 Tension-Induced Buckling in Serpentine Structures -- 10.2.2.5 Tension-Induced Buckling in Kirigami Structures -- 10.3 Applications in Stretchable Devices -- 10.3.1 Stretchable Sensors -- 10.3.2 Stretchable Batteries -- 10.3.3 Other Stretchable Electronics -- 10.4 Applications in Healthcare -- 10.4.1 Biosensors -- 10.4.2 Biological Interfaces -- 10.5 Conclusion and Outlook -- Acknowledgments -- References -- Part III Applications -- Chapter 11 Spherical Indentation Behavior of Soft Electronics -- 11.1 Spherical Indentation of the Semi-infinite Solid -- 11.1.1 General Solution for Elastic Solid with Displacement Function -- 11.1.2 Indentation Behavior of Revolution Indenter -- 11.1.3 Indentation Behavior of Spherical Indenter -- 11.2 Applications in a Force-Softness Bimodal Sensor Array for Human Body Feature Identification -- 11.2.1 Design of the Spherical Indenter-Based Force-Softness Sensor -- 11.2.1.1 The First Stage -- 11.2.1.2 The Second Stage -- 11.2.2 Integration of the Force-Softness Sensor Array: Tactile Glove -- 11.2.3 Applications in Body Feature Identification -- 11.3 Applications in a Self-Locked Young's Modulus Sensor for Quantifying the Softness of Swollen Tissues in the Clinic -- 11.3.1 Design of the Fingertip Modulus Sensor.