Table 1.

Dynamic covalent bonds used in dual dynamic networks (DDNs): Dynamic bonds, stimuli triggering the exchange, polymeric systems developed (with a representative example from the literature), and imparted functions (PUR = polyurethane, SMP = shape-memory polymer, IPN = interpenetrated network).

Dynamic Bonds	Triggers	Polymeric Systems	Imparted Functions
Diels-Alder cycloadduct	T	PURs [36], SMPs [37], hydrogels [38], IPNs [39], combined networks [40]	reshapeability, enhanced mechanical properties, self-healing ability, facilitated synthesis, structural stability, shape memory
Disulfide	redox, light, T, pH	PURs [41], SMPs [42], vitrimers [43], hydrogels [44], IPNs [45]	reshapeability, self-healing ability, enhanced mechanical properties, responsiveness, facilitated synthesis, shape memory
Acylhydrazone	pH	supramolecular polymers [46], hydrogels [44], IPNs [47]	reshapeability, self-healing ability, responsiveness, facilitated synthesis, injectability
Oxime	T, pH, addition of molecules	hydrogels [48]	structural stability, self-healing ability, enhanced mechanical properties
Imine	T, pH, addition of molecules	SMPs [49], vitrimers [50], combined networks [51]	reshapeability, self-healing ability, enhanced mechanical properties, facilitated synthesis
Urethane/Urea	T, catalysts	SMPs [52], vitrimers [53]	reshapeability, enhanced mechanical properties, facilitated synthesis
Ester	T, catalysts	SMPs [54], vitrimers [54]	reshapeability, facilitated synthesis, shape memory
Boronic ester	T, pH, addition of molecules	SMPs [55], vitrimers [56], hydrogels [48], IPNs [47], combined networks [51]	reshapeability, self-healing ability, enhanced mechanical properties, responsiveness, facilitated synthesis
C–C (scission)	mechanical force, T	PURs [57]	self-healing ability, responsiveness, enhanced mechanical properties
Cycloadduct of cinnamic acid derivatives	light	SMPs [58]	shape memory
Allyl sulfide and trithiocarbonate	T, radicals, catalysts	SMPs [59], vitrimers [29]	reshapeability, self-healing ability, facilitated synthesis