The Mechanics of Hydrogels: Mechanical Properties, Testing, and Applications (Elsevier Series in Mechanics of Advanced Materials)

The Mechanics of Hydrogels: Mechanical Properties, Testing, and Applications
Copyright
Elsevier Series in Mechanics of Advanced Materials
List of contributors
Preface
1. Mechanical characterization of hydrogels
	1.1 Introduction
	1.2 Classification of hydrogels
		1.2.1 Source
		1.2.2 Polymer composition
		1.2.3 Polymer network configuration
		1.2.4 Type of cross-linking
	1.3 Mechanical testing of hydrogels
		1.3.1 Macroscale testing
			1.3.1.1 Tension test
			1.3.1.2 Compression test
			1.3.1.3 Fracture test
		1.3.2 Indentation testing
		1.3.3 Microscopy-based testing
	1.4 Key mechanical properties
		1.4.1 Elastic properties
		1.4.2 Failure stress and fracture toughness
		1.4.3 Time-dependent properties
	1.5 Concluding remarks
	References
2. Deformation and fracture behaviors of long-fiber hydrogels
	2.1 Introduction
		2.1.1 Background
		2.1.2 Hydrogel structure
	2.2 Experimental approaches
		2.2.1 Universal tests
		2.2.2 Microstructural observations
	2.3 Deformation behaviors
		2.3.1 Inelastic behavior of fibrous network
			2.3.1.1 Tensile behavior
			2.3.1.2 Compressive behavior
		2.3.2 Effect of liquid phase
	2.4 Fracture behavior
	2.5 Summary and conclusions
	References
3. Linear and nonlinear deformation behavior of hydrogels
	3.1 Introduction
	3.2 The linear theory of chemomechanical coupling
	3.3 Analytical solutions of linear chemomechanical coupling problems
		3.3.1 The uniaxial stress problem for hydrogel rod
		3.3.2 The centrosymmetric problem in spheric hydrogel
		3.3.3 Hollow cylindrical hydrogel considering the end bending effect
		3.3.4 The plain-strain problem in hydrogel cylinder
	3.4 Nonlinear swelling modeling of hydrogel
		3.4.1 Nonlinear constitutive model
		3.4.2 The material constitutive model
		3.4.3 The variation formulation
		3.4.4 Transient swelling of a square hydrogel with a hole
	3.5 Conclusions
	Acknowledgments
	References
4. Mechanical testing of hydrogels
	4.1 Introduction
	4.2 Standard mechanical tests
		4.2.1 Tensile
		4.2.2 Compression
	4.3 Indentation
		4.3.1 Micro- and nanoindentation
		4.3.2 Spherical indentation
		4.3.3 Freestanding spherical indentation
	4.4 Nondestructive elastography
		4.4.1 Ultrasound elastography
		4.4.2 Optical coherence elastography
		4.4.3 Brillouin microscopy
	4.5 Conclusions
	References
5. Multi-scale instrumented indentation of hydrogels
	5.1 Introduction
	5.2 Theoretical fundamentals
		5.2.1 Classical elastic contact models
			5.2.1.1 Nonadhesion normal contact of elastic solids
			5.2.1.2 Johnson–Kendall–Roberts adhesion contact theory of elastic solids
		5.2.2 Constitutive models of hydrogels
			5.2.2.1 Hyperelastic model
			5.2.2.2 Viscoelastic model
			5.2.2.3 Poroelastic model
	5.3 Multi-scale indentation experimental technique
		5.3.1 Measurement instruments
		5.3.2 Indenter's tip selection
		5.3.3 Determination of the initial contact surface
		5.3.4 Test methods
		5.3.5 Material parameter identification methods
			5.3.5.1 Elastic modulus and hardness
			5.3.5.2 Nonlinear elastic properties
			5.3.5.3 Viscoelastic properties
			5.3.5.4 Poroelastic properties
	5.4 Typical applications
		5.4.1 Indentation of polyvinyl alcohol hydrogels
		5.4.2 Indentation of articular cartilage
	5.5 Conclusions and future perspectives
	Acknowledgments
	References
6. Fatigue of hydrogels
	6.1 Characterization of fatigue
	6.2 Fatigue of hydrogels with long chains as elastic dissipators
		6.2.1 Experimental data of fatigue of hydrogels
			6.2.1.1 PAAm hydrogels
			6.2.1.2 PNIPAM hydrogels
			6.2.1.3 PVA hydrogels
			6.2.1.4 PAAm-G8 hydrogels
			6.2.1.5 PAAm-PAMPS double-network hydrogels
			6.2.1.6 PAAm-Ca-alginate double-network hydrogels
			6.2.1.7 PAAm-PVA double-network hydrogels
			6.2.1.8 PVA-PAA double-network hydrogels
	6.3 Lake–Thomas model
		6.3.1 Lake–Thomas model for elastomers
		6.3.2 Lake–Thomas model adapted for single-network hydrogels
		6.3.3 Lake–Thomas model adapted for double-network hydrogels
	6.4 Fatigue of hydrogels with heterogeneous structures
		6.4.1 Chain crystallization
		6.4.2 Fiber composite
		6.4.3 Crystallized fibers
	6.5 Fatigue of hydrogel adhesion
		6.5.1 Long chain as elastic dissipater
		6.5.2 Crystallization
	6.6 Prospects
	References
7. Dynamic behaviors of the hydrogel
	7.1 Introduction
	7.2 Experiment
		7.2.1 Hydrogel preparation
		7.2.2 Static compressive experiment
		7.2.3 SHPB experiment
	7.3 Results and discussion for static compressive experiments
	7.4 Results and discussion for impact experiments
	7.5 Concluding remarks
	7.6 Expectation
	References
8. Numerical modeling of hydrogels: from microscopic network to macroscopic material
	8.1 Introduction
		8.1.1 Background
		8.1.2 Aim
		8.1.3 Method
		8.1.4 Finite-element analysis
	8.2 Fundamental concepts
		8.2.1 Fiber orientation and distributions
		8.2.2 Affine and nonaffine networks
		8.2.3 Fiber curvature
	8.3 Numerical modelling
		8.3.1 Continuous models of fibrous networks
		8.3.2 Discontinuous models of fibrous networks
		8.3.3 Periodic and nonperiodic boundary conditions
		8.3.4 Size effects of mechanical properties
		8.3.5 Microstructural effects on mechanics of fibrous networks
		8.3.6 Fiber-to-fiber connections
	8.4 Conclusion
	References
9. Multiscale modeling of hydrogels
	9.1 Introduction
	9.2 Nanoscale modeling of hydrogels
		9.2.1 Microscale modeling methods—molecular dynamics and dissipative particle dynamics
		9.2.2 Thermal conduction in hydrogels (MD simulation)
		9.2.3 The effect of solvent water in hydrogel
		9.2.4 Hydrogel models and dissipative particle dynamics
	9.3 Mesoscale modeling of hydrogels (new insights)
		9.3.1 What does mesoscale modeling of hydrogels refer to?
		9.3.2 Available theoretical tools for mesoscale for hydrogel modeling
		9.3.3 The foundation of the complex network science
		9.3.4 Establish a complex network model for hydrogels
		9.3.5 Applications of mesoscale approach modeling for hydrogel
			9.3.5.1 Elastic modulus from the perspective of complex network science
			9.3.5.2 Fracture criterion of hydrogels from the perspective of complex network science
	9.4 Macroscale modeling of hydrogels
		9.4.1 The model of salt concentration–sensitive hydrogels
		9.4.2 The model of pH-sensitive hydrogels
		9.4.3 The model of temperature-sensitive hydrogels
		9.4.4 The model of photo-thermal–sensitive hydrogel
		9.4.5 The model of magnetic-sensitive hydrogel
		9.4.6 The implementation of various models into ABAQUS
	9.5 Discussion on methods for modeling hydrogels
	9.6 Conclusions
	Acknowledgments
	References
10. Modeling of stimuli-responsive hydrogels: a transient analysis
	10.1 Introduction
	10.2 Formulation
		10.2.1 Chemical field based on the law of mass conservation
		10.2.2 Electric field
		10.2.3 Mechanical field based on the law of momentum conservation
		10.2.4 Fixed charge density based on the material law
		10.2.5 Nondimensionalization
		10.2.6 Boundary conditions
		10.2.7 Initial conditions
		10.2.8 Transient algorithm
		10.2.9 Kinetic swelling ratio
		10.2.10 Diffusion coefficient
	10.3 Model examination for ionic-strength–sensitive hydrogel
		10.3.1 Kinetic reversible swelling/shrinking of HMDT
		10.3.2 Kinetic reversible swelling/shrinking of CPMA
		10.3.3 Kinetic shrinking of SMA
	10.4 Parameter studies for ionic-strength–sensitive hydrogel
		10.4.1 Analysis of reversible kinetics
		10.4.2 Influence of initial fixed charge density
		10.4.3 Influence of Young's modulus
	10.5 Parameter studies for electric-sensitive hydrogel
		10.5.1 Kinetics of diffusive ion concentrations
		10.5.2 Variation of distributive electric potential with time
		10.5.3 Variation of distributive displacement of the hydrogel with time
	10.6 Summary and conclusions
	References
11. Mechanically driven phase transition of physical hydrogels
	11.1 Introduction
	11.2 Formulation
		11.2.1 Free energy density
		11.2.2 Governing equations
			11.2.2.1 Mechanical field
			11.2.2.2 Chemical field
			11.2.2.3 Thermal field
		11.2.3 Constitutive equations
	11.3 Results and discussion
		11.3.1 Equilibrium analysis for steady-state subject to hydrostatic loading
		11.3.2 Transient analysis of spherically symmetrical phase transition
	11.4 Conclusions
	Acknowledgments
	References
12. Large deformation behavior of magnetic hydrogels
	12.1 Introduction
	12.2 Magneto-chemo-mechanical model
	12.3 Magneto-chemo-electro-mechanical model
	12.4 Large deformation of magnetic hydrogels
		12.4.1 Deformation of magnetic-sensitive hydrogel
		12.4.2 Deformation of dual magnetic-pH–sensitive hydrogel
		12.4.3 Design of the magnetic-sensitive hydrogel–based device
	12.5 Conclusion
	Acknowledgments
	References
13. Enzyme functionalized hydrogels: relationship between stimuli and mechanical response
	13.1 Introduction
	13.2 Methodology
	13.3 Results and discussion
		13.3.1 Effect of enzyme concentration
		13.3.2 Effect of pH and temperature
		13.3.3 Mechanical response versus (urea) stimuli
		13.3.4 Mechanical response versus (salt) stimuli
	13.4 Conclusion
	Acknowledgment
	References
Index
A
B
C
D
E
F
G
H
I
J
K
L
M
N
O
P
Q
R
S
T
U
V
Y
Z