Figure 6.

(a) The synthesis of supramolecular polyureas and chemical structures of the designed noncovalently bonded diamine monomers, covalent diamine/triamine monomers and diisocyanate monomers. Schematic diagram of the recycling process of the resultant polyureas based on the covalent-noncovalent crosslinking strategy [162]. Copyright 2020, Wiley-VCH. (b) The monomers, prepolymers and crosslinking agents used in the synthesis of copolyester, and a schematic network fragment of the copolyester. Schematics of the network structure before and after crystallization-melting transition. Reproduced with permission [163]. Copyright 2019, Wiley-VCH. (c) Schematic healing mechanism of the resultant hydrogel physical and chemical crosslinking networks. Digital pictures during cut, healing for 180 s and stretching after healing. Reproduced with permission [167]. Copyright 2017, Wiley-VCH. (d) Schematic synthesis procedures of self-healing hydrogels with dynamic host-guest noncovalent crosslinking network and covalently linked network design. Right pictures are corresponding self-healing process photos. Reprinted with permission from ref. [168]. Copyright 2019, Royal Society of Chemistry.