Table 2 Summary of recent self-healing systems based on supramolecular hydrogen bonds and metal-coordination crosslinking: mechanical characteristics, self-healing-conditions and efficiencies
From: Advances in self-healing supramolecular soft materials and nanocomposites
| Material composition | Tg (°C) | Healing motif, condition, and efficiency | Remarks | Ref. |
|---|---|---|---|---|
| MG-SHPU | − 4.45 | H-bonding, NIR radiation, and modulus of toughness, 40% | 0.75 wt% MG (MG075) gave maximum healing efficiency up to 40%. Intermolecular diffusion of SHPU which was accelerated by thermal energy generated by NIR absorptions | [106] |
| RGO-HPUs | NA | H-bonding, MW energy and app. 100% | Composite is also incorporated with iron oxide/TiO2. This combined composites exhibited an excellent shape memory, self-healing and self-cleaning properties | [107] |
| H-bonding, direct sunlight and NA | ||||
| G-PAM-PAA | NA | H-bonding, thermal healing and app. 100% | Above 10 wt% of graphene yields the self-healing behavior | [84] |
| GO-HBN | − 5 to 9 | H-bonding, RT, ~ 60% | Protecting barrier for electronic wires and devices, sealing layer for gas systems | [102] |
| FG-TPU | ~20–30 | H-bonding, IR and MW radiation, and ~ 98% | FG-TPU composites exhibit improved mechanical properties and could be healed effectively and rapidly by IR, electricity, and electromagnetic wave | [84] |
| µNi-M-NH2 | − 20 to 10 | H-bonding, RT, 15 min, ~ 90%, | Addition of nanostructured µNi particles with nano-structured surfaces significantly enhances the mechanical properties | [108] |
| BNNSs-supramolecules | − 7 to 43 | H-bonding, ~ 100%, 85 °C, 30 min | Polymer nanocomposite with 8 vol% BNNSs exhibits two orders of magnitude improvement in electrical resistivity over that of the pristine polymer network | [109] |
| UPy-K-UPy/CNC-UPy | − 50 | H-bonding, UV-light, 20–80 s, ~ 100% | H-bonded UPy supramolecular polymer and CNCs decorated with the same supramolecular motif show an attractive combination of high stiffness, high strength, and rapid and efficient optical healing | [75] |
| Si-GO-HPU | − 50 to − 51 | H-bonding, UV-MW, 4–6 min ~ 100% | The surfaces of the HPU/Si-GO nanocomposites also displayed inherent hydrophobicity without any additional surface modification | [110] |
| CNT-PU | NA | Coordination bond, NIR-light, 90 °C, 1 h, ~ 93% | Zn2+ coordinated metallo-supramolecular CNT-PU nanocomposite that showed a strong, tough, and elastic mechanical properties and was able to self-heal multiple times | [89] |
| V2O5-PDMS-g-PUR | − 12.5 to − 53.1 | H-bonding, 50 °C, 120 min, 85.4% | V2O5 nanofibers enhances the mechanical properties and healing efficiency of the PDMS-g-PUR through a reversible hydrogen bonding mechanism | [111] |
| GO-PDMAA | NA | H-bonding, NIR radiation, 3 min, 96% | Self-healable GO-clay-PDMAA hybrid hydrogels with high extensibility and mechanical strength contributed by both hectorite clay and GO as cross-linking agents | [112] |
| GO-PAA | NA | H-bonding, NIR radiation, 30 °C, 24 h, ~ 100% | The strong interactions between the PAA chains and the GO sheets are essential to the mechanical strengths of the healed gels | [113] |
| GO-PAACA | Coordination bond and H-bonding, Ph7, 10 min, ~ 100% | The polar groups of the PAACA side chains and oxygen-containing groups of GO nanosheets via coordination interactions | [114] | |
| HPU-SRGO | NA | H-bonding, 50-60 s in MW, 1–3 min in sunlight, ~ 96.8% | Shape memory of HPU and energy absorbing capability of SRGO-assisted melting, diffusion, and rearrangement of the soft segment of HPU to crack place | [115] |
