Self-Healing Polymer-Based Systems

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Copyright
Contents
List of Contributors
1 Self-healing polymeric systems—fundamentals, state of art, and challenges
	1.1 Introduction
		1.1.1 Extrinsic self-healing in polymeric systems
		1.1.2 Intrinsic self-healing in polymeric systems
	1.2 Role of nanofillers in self-healing polymeric systems
	1.3 Key developments in the field of self-healing polymeric systems
	1.4 Challenges for fabricating self-healing materials based on polymeric systems
	1.5 Conclusions
	References
2 Types of chemistries involved in self-healing polymeric systems
	2.1 Introduction: chemical aspects in self-healing process
		2.1.1 Extrinsic and intrinsic self-healing
	2.2 Key requirements of self-healing process
	2.3 Dynamic covalent network in self-healing
	2.4 Thermoreversible Diels–Alder and retro Diels–Alder chemistry
	2.5 Photoinduced self-healing: [2+2] cycloaddition
		2.5.1 [4+4] Cycloaddition reactions
	2.6 Chemical transformations involved in self-healing
		2.6.1 Thiol-ene click chemistry
		2.6.2 Dynamic exchange of disulfide bonds
		2.6.3 Dynamic chemistry of selenium
	2.7 Reversible covalent reaction involved in self-healing
		2.7.1 Dynamic reversible boronate ester bond
		2.7.2 Dynamic reversibility of hindered urea bond
		2.7.3 Dynamically reversible alkoxyamines fission/radical recombination
		2.7.4 Reversible dynamic covalent Schiff-base (imine) linkage-based self-healing chemistry
		2.7.5 Reversible covalent acylhydrazone bond in self-healing chemistry
	2.8 Chemical transformations through involved reaction in self-healing
		2.8.1 Exchangeable hydrazide Michael adduct linkages
		2.8.2 Dynamic siloxane bond exchange
		2.8.3 Dynamic covalent exchange network in polyesters
		2.8.4 Self-healing based on exchangeable reactions involving hypervalent iodine
	2.9 Supramolecular noncovalent interaction
		2.9.1 Hydrogen-bonding-based self-healing
		2.9.2 Self-healing involved through electrostatic interactions
			2.9.2.1 Ionomeric or ionic mechanism
			2.9.2.2 Self-healing through ionic salts
			2.9.2.3 Magnesium ions (Mg2+)-based self-healing mechanism
			2.9.2.4 Calcium ions (Ca2+)-based self-healing mechanism
			2.9.2.5 Frustrated Lewis pair polymers as responsive self-healing gels
		2.9.3 Self-healing based on van der Waals force of attraction
		2.9.4 Reversible metallosupramolecular polymer
		2.9.5 Host–guest interactions
		2.9.6 π-Interactions based self-healing polymer
		2.9.7 Hydrophobic interactions
		2.9.8 Interpenetrating polymer network for self-healing
	2.10 Chemistries involved in microcapsule-based self-healing polymeric system
		2.10.1 Microcapsule mediated ring-opening metathesis polymerization
		2.10.2 Azide-alkyne click chemistry
		2.10.3 Controlled radical polymerization in microcapsule system
			2.10.3.1 Other microcapsule-embedded systems
		2.10.4 Vascular-based self-healing system
			2.10.4.1 Macrovascular system
			2.10.4.2 Microvascular-based self-healing
	2.11 Conclusions
	References
3 Self-healing polymers: from general basics to mechanistic aspects
	3.1 Introduction
	3.2 General mechanism of self-healing polymers
	3.3 Concepts for the design of self-healing polymers
	3.4 Extrinsic self-healing polymers
	3.5 Intrinsic self-healing polymers
	3.6 Other mechanistic aspects
	3.7 Conclusions
	References
4 Shape memory-assisted self-healing polymer systems
	4.1 Introduction
	4.2 Shape memory and self-healing mechanisms
		4.2.1 Shape memory mechanism
		4.2.2 Intrinsic self-healing of polymers
			4.2.2.1 Covalent self-healing
			4.2.2.2 Noncovalent self-healing
	4.3 Shape memory-assisted self-healing
		4.3.1 Thermoplastic polymers
		4.3.2 Elastomers
		4.3.3 Thermoset polymers
		4.3.4 Extrinsic shape memory-assisted self-healing
	4.4 Applications
	4.5 Conclusions
	References
5 Characterization of self-healing polymeric materials
	5.1 Introduction
	5.2 Methods for evaluating self-healing behavior of the polymeric composites
		5.2.1 Qualitative methods
			5.2.1.1 Visualization techniques
			5.2.1.2 Acoustical microscopy
			5.2.1.3 X-ray microtomography
			5.2.1.4 Evaluation of self-healing reaction heat
		5.2.2 Quantitative methods
			5.2.2.1 Tensile testing
			5.2.2.2 Bending testing
			5.2.2.3 Tapered double cantilever beam
			5.2.2.4 Ballistic impact
			5.2.2.5 Dynamic mechanical thermal analyses
	5.3 Methods for evaluating self-healing behavior of the polymeric coatings
		5.3.1 Qualitative methods
			5.3.1.1 Visual inspection and optical microscopy
			5.3.1.2 Scanning electron microscopy
			5.3.1.3 Confocal microscopy
			5.3.1.4 Scanning electrochemical microscopy
			5.3.1.5 Scanning vibrating electrode technique
		5.3.2 Quantitative methods
			5.3.2.1 Healing of hydrophobicity
			5.3.2.2 Atomic force microscopy
			5.3.2.3 Tribological properties
			5.3.2.4 Corrosion assessment tests
				5.3.2.4.1 Potentiostatic and potentiodynamic techniques
				5.3.2.4.2 Electrochemical impedance spectroscopy
	5.4 Summary and outlook
	References
6 Role of nanoparticles in self-healing of polymeric systems
	6.1 Introduction
	6.2 Self-healing polymer using metal nanoparticles
	6.3 Self-healing polymer using inorganic nanoparticles
	6.4 Self-healing polymer using organic nanoparticles
		6.4.1 Self-healing by shape-memory organic nanoparticles
		6.4.2 Self-healing by organic micro- or nanocapsules
		6.4.3 Evaluation of self-healing capability
			6.4.3.1 Crack growth method
			6.4.3.2 Beam on elastic foundation method
			6.4.3.3 Direct tensile tests
		6.4.4 Introduction of a real application of self-healing nanocapsules
	6.5 Further advice
	References
7 Self-healing biomaterials based on polymeric systems
	7.1 Introduction
	7.2 Self-healing biomaterials in tissue engineering
		7.2.1 Self-healing hydrogels
			7.2.1.1 Mechanism
				7.2.1.1.1 Noncovalent bonding
					7.2.1.1.1.1 Electrostatic interaction
					7.2.1.1.1.2 Hydrogen bonding
					7.2.1.1.1.3 Host–guest interaction
					7.2.1.1.1.4 Metal–ligand coordination
					7.2.1.1.1.5 Hydrophobic interactions
					7.2.1.1.1.6 Crystallization
				7.2.1.1.2 Dynamic covalent bonding
					7.2.1.1.2.1 Diels–Alder reaction
					7.2.1.1.2.2 Thiol–disulfide exchange
					7.2.1.1.2.3 Imine bonds
					7.2.1.1.2.4 Acylhydrazone bonds
					7.2.1.1.2.5 Oxime bonds
			7.2.1.2 The evaluation of self-healing efficiency
			7.2.1.3 Applications in tissue engineering
				7.2.1.3.1 Tissue adhesives
				7.2.1.3.2 Cell scaffolds
		7.2.2 Self-healing films
			7.2.2.1 Mechanism
			7.2.2.2 Applications in tissue engineering
				7.2.2.2.1 Cell coculture
				7.2.2.2.2 Biosensor
	7.3 Self-healing biomaterials in drug/gene delivery systems
		7.3.1 Injectable hydrogels
		7.3.2 Particles and capsules
	7.4 Self-healing functional surfaces
		7.4.1 Antibacterial and antifouling surfaces
		7.4.2 Surface-mediated drug delivery
		7.4.3 Challenges
	7.5 The characterization of self-healing
	7.6 New opportunities and challenges
		7.6.1 3D printing
		7.6.2 Wound dressing
		7.6.3 Electronic skin
	References
8 Self-healing Diels–Alder engineered thermosets
	8.1 Fundamentals of self-healing
	8.2 Types of self-healing systems
	8.3 Diels–Alder reaction
		8.3.1 Kinetics and thermodynamics of Diels–Alder reaction
		8.3.2 Diels–Alder reaction of furan/maleimide
	8.4 Diels–Alder-based healable thermosets
		8.4.1 Applications of Diels–Alder-based self-healing networks
			8.4.1.1 Healable Diels–Alder-based hydrogels
			8.4.1.2 Diels–Alder-based healable rubbers
			8.4.1.3 Diels–Alder-based healable polymer composites
				8.4.1.3.1 Healing of Diels–Alder-based polymer composites by nonthermal methods
				8.4.1.3.2 Self-healing Diels–Alder-based nanocomposites
					8.4.1.3.2.1 Graphene-based Diels–Alder nanocomposites
					8.4.1.3.4.2 Carbon nanotube-based Diels–Alder nanocomposites
					8.4.1.3.4.3 Silver nanowires-based Diels–Alder nanocomposites
			8.4.1.4 Healable Diels–Alder-based polymer coatings
			8.4.1.5 Diels–Alder-based healable polymer adhesives
			8.4.1.6 Diels–Alder-based self-healing actuators and robots
	8.5 Summary and outlook
	References
9 Self-healing polymeric coatings containing microcapsules filled with active materials
	9.1 Introduction
	9.2 Requirements for designing a self-healing coating
	9.3 Microcapsule-based self-healing systems
	9.4 Microcapsule preparation methods
	9.5 Materials selection for core and shell components of microcapsules
	9.6 Limitations and shortcomings of microcapsule-embedded coatings
	9.7 Summary
	References
10 Capsule-based self-healing polymers and composites
	10.1 Introduction
	10.2 Capsule synthesis and characterization
	10.3 Self-healing polymers and composites
	10.4 Self-healing coatings
	10.5 Conclusions and future trends
	References
11 Ionomers as self-healing materials
	11.1 Introduction
	11.2 Materials, chemistry, and fundamentals
	11.3 The self-healing mechanisms
	11.4 Activation methods
	11.5 Applications
	11.6 Summary
	References
12 Self-healing materials utilizing supramolecular interactions
	12.1 Intrinsic self-healing systems
		12.1.1 Supramolecular bonds
		12.1.2 Hydrogen bonding
		12.1.3 Metal coordination
		12.1.4 Host–guest interactions
		12.1.5 Dynamic covalent chemistry
	12.2 Main-chain supramolecular polymers
		12.2.1 Supramolecular polymerizations
		12.2.2 Isodesmic supramolecular polymerization
		12.2.3 Ring-chain supramolecular polymerization
		12.2.4 Cooperative supramolecular polymerization
		12.2.5 Directional noncovalent interactions
	12.3 Self-healing materials driven by metal coordination
		12.3.1 Early development
		12.3.2 Network formation and self-healing
		12.3.3 Ligand systems
		12.3.4 Naturally occuring and bioinspired self-healing systems
		12.3.5 Photoresponsive systems
		12.3.6 Self-assembly: directional bonding approaches
			12.3.6.1 Metal-organic framework
	12.4 Self-healing mediated by electrostatic interactions
		12.4.1 Electrostatic self-assembly
		12.4.2 Bulk ionomer self-healing materials
		12.4.3 Self-healing poly(ionic liquids)
	12.5 Host–guest interactions in self-healing materials
		12.5.1 Introduction to host–guest interactions
		12.5.2 Mechanism of self-healing based on host–guest interactions
		12.5.3 Design of self-healing, host–guest materials
		12.5.4 Self-healing materials utilizing cyclodextrin
		12.5.5 Self-healing materials utilizing crown ethers
		12.5.6 Self-healing materials utilizing cucurbiturils
		12.5.7 Enhancing mechanical properties in host–guest self-healing materials
	12.6 Dynamic covalent self-healing materials
		12.6.1 Introduction to dynamic covalent bonds
		12.6.2 Self-healing from dynamic condensation reactions
			12.6.2.1 Acylhydrazone bonds
			12.6.2.2 Boronate ester bonds
			12.6.2.3 Imine and enamine bonds
		12.6.3 Reversible cycloaddition reactions
			12.6.3.1 Reversible Diels–Alder
		12.6.4 DCB exchange through chemical or catalytic stimuli
		12.6.5 Photo-induced dynamic covalent self-healing
	12.7 Hydrogen bonding in self-healing systems
		12.7.1 Hydrogen bonding
		12.7.2 Self-complementary hydrogen bonding in self-healing materials
		12.7.3 Self-healing polymers utilizing weak hydrogen bonding
		12.7.4 Combination of hydrogen bonding and dynamic covalent bonds
	12.8 Conclusions and future outlook
	References
13 Self-healing hydrogels
	13.1 Introduction
		13.1.1 Gel and hydrogel
		13.1.2 Hydrosol and hydrogel
	13.2 Self-healing
	13.3 Self-healing and its characterization
		13.3.1 Extrinsic self-healing
		13.3.2 Intrinsic self-healing
	13.4 Chemistry involved in intrinsic self-healing
		13.4.1 Reversible covalent bonds
			13.4.1.1 Reversible cycloaddition reactions
			13.4.1.2 Exchange reactions
			13.4.1.3 Stable free radical-mediated reshuffle reactions
			13.4.1.4 Heterocyclic compounds and carbohydrates in self-healing polyurethanes
		13.4.2 Supramolecular chemistry
			13.4.2.1 Hydrogen bonds
			13.4.2.2 π–π Stacking interactions
			13.4.2.3 Metal–ligand interaction
			13.4.2.4 Ionic interaction
			13.4.2.5 Host–guest interaction
	13.5 Self-healing process
		13.5.1 Autonomic self-healing hydrogels
		13.5.2 Nonautonomic self-healing hydrogels
	13.6 Classification of self-healing hydrogels
		13.6.1 Inorganic-based self-healing hydrogels
		13.6.2 Polymer-based self-healing hydrogels
		13.6.3 Nanocomposite-based self-healing hydrogels
	13.7 Mechanism of self-healing of hydrogels
		13.7.1 Physically (diffusion) self-healing mechanism
		13.7.2 Chemically self-healing mechanism
	13.8 Factors impact on self-healing mechanism
		13.8.1 Separation time
		13.8.2 Self-healing time
		13.8.3 Temperature
		13.8.4 Chain length
		13.8.5 The content of nanomaterials
	13.9 Sacrificial bonds
	13.10 Nature and mechanisms of sacrificial bonds
		13.10.1 Sacrificial bonds in biological materials
		13.10.2 Constitutive theories of sacrificial bonding systems
	13.11 Inspired sacrificial bonds in artificial polymeric materials
		13.11.1 Sacrificial covalent bonds
		13.11.2 Sacrificial noncovalent bonds
	13.12 Sacrificial bonds in hydrogels
		13.12.1 Sacrificial ionic bonds
		13.12.2 Sacrificial hydrogen bonds
		13.12.3 Sacrificial metal–ligand coordination bonds
		13.12.4 Sacrificial hydrophobic interactions
		13.12.5 Sacrificial host–guest complexes
	13.13 Metal–ligand polymer hydrogels
		13.13.1 Cross-linked hydrogels via metal coordination
		13.13.2 Covalently cross-linked hydrogels
		13.13.3 Hybrid cross-linked hydrogels
	13.14 Self-healing gels mechanism based on constitutional dynamic chemistry
	13.15 Natural polymer-based hydrogels
		13.15.1 Alginate
		13.15.2 Agarose-based self-healing hydrogels
		13.15.3 Chitosan
		13.15.4 Cellulose
		13.15.5 Hydroxyethyl cellulose
		13.15.6 Dextrin-based self-healing hydrogels
		13.15.7 Guar gum-based self-healing hydrogels
		13.15.8 Gelatin-based self-healing hydrogels
		13.15.9 Glycogen-based self-healing hydrogels
		13.15.10 Hyaluronic acid-based hydrogels
		13.15.11 Xanthan-gum-based self-healing hydrogels
	13.16 Recent development in miscellaneous application fields
		13.16.1 Superabsorbent hybrid hydrogels
		13.16.2 Conductive polymer hydrogels
		13.16.3 Polysaccharide-based natural hydrogels
		13.16.4 Protein-based hydrogels
		13.16.5 Hydrogels for energy applications
	References
14 A continuum mechanics approach to the healing efficiency of extrinsic self-healing polymers
	14.1 Introduction
	14.2 Finite deformation kinematics: elastic, plastic, damage, and healing in polymers
	14.3 Plastic deformation in polymers
	14.4 Continuum damage and healing mechanics
		14.4.1 Scalar damage-healing variables for isotropic problems
		14.4.2 Anisotropic damage-healing problems
	14.5 Physically consistent evolution laws for the damage and healing processes
		14.5.1 Thermodynamic consistent damage and healing model
		14.5.2 Mechanisms-based phenomenological healing models
	14.6 Concluding remarks
	References
15 Self-healing fiber-reinforced polymer composites for their potential structural applications
	15.1 Introduction
	15.2 Scope of self-healing in fiber-reinforced polymer composites
	15.3 Extrinsic self-healing approaches for fiber-reinforced polymer composites
		15.3.1 Microcapsule-based self-healing
		15.3.2 Hollow fiber-based self-healing
		15.3.3 Microvascular-based self-healing
	15.4 Intrinsic self-healing approach for fiber-reinforced polymer composites
	15.5 Thermoreversible healing of FRP
	15.6 Assessment of self-healing efficiency for fiber-reinforced polymer composites
	15.7 Conclusions
	References
16 Self-healing polymeric coating for corrosion inhibition and fatigue repair
	16.1 Background of self-healing and corrosion inhibition
	16.2 Self-healing and corrosion inhibitor materials
		16.2.1 Self-healing materials
			16.2.1.1 Single catalyst with microcapsules
			16.2.1.2 Dual capsule-based system
		16.2.2 Corrosion inhibitors
			16.2.2.1 Types of corrosion inhibitors
			16.2.2.2 Anodic corrosion inhibitors
			16.2.2.3 Nitrites
			16.2.2.4 Molybdates
			16.2.2.5 Cathodic corrosion inhibitor
			16.2.2.6 Organic inhibitors
	16.3 Case study for self-healing material and corrosion inhibitors
		16.3.1 Green synthesis of self-healing corrosion-inhibiting coating using neem oil as self-healing and corrosion inhibitor
		16.3.2 Synthesis of nanocapsules using ultrasound and conventional method
	16.4 Polymer capsules-based self-healing coating for corrosion inhibition
		16.4.1 Self-healing capsules based on polymeric materials
	16.5 Nanocontainer-based self-healing approach for corrosion inhibition
	16.6 Clay-based self-healing materials for corrosion inhibition
		16.6.1 Commercial applications and future prospectus
	Conclusions
	References
17 Applications of self-healing polymeric systems
	17.1 Introduction
	17.2 Application in wound healing
	17.3 Application in tissue engineering
	17.4 Application in three-dimensional printing
	17.5 Application in drug delivery
	17.6 Application in anticorrosion coating
	17.7 Application in electronic application
	17.8 Application in aerospace applications
	17.9 Conclusions
	References
Index
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