Towards Dynamic but Supertough Healable Polymers through Biomimetic Hierarchical Hydrogen‐Bonding Interactions

Abstract

Ab iomimetic (titin protein molecular structure) strategy is reported for preparing transparent and healable elastomers featuring supertoughness (345 MJ m À3 )a nd high tensile strength (44 MPa) after self-healing enabled by hierarchical (single,d ouble,a nd quadruple) hydrogen-bonding moieties in the polymer backbone.T he rigid domain containing hierarchicalH -bonds formed with urethane,u rea, and 2ureido-4[1H]-pyrimidinone groups leads to adurable network structure that has enhanced mechanical properties and is also dynamic for rapid self-healing.H ealable polymers with hierarchical hydrogen-bonding interactions show excellent recoverability and high energy dissipation owing to the durable interaction between polymer chains.T his biomimetic strategy of using hierarchicalh ydrogen bonds as building blocks is an alternative approach for obtaining dynamic,s trong, yet smart self-healing polymers for heavy-duty protection materials and wearable electronics.

Room-temperature autonomous self-healing glassy polymers with hyperbranched structure

“…As the temperature increases, the proton peak of -NHin the amide groups shows an upfield shift and meanwhile the proton peak of methylene beside -NH 2 and -NH-shows a downfield shift. Such shifts are observed to begin at 25°C, indicating that a part of the hydrogen bonds is already very dynamic at room temperature (46), which will facilitate the self-healing under this condition.…”

Toughening a Self‐Healable Supramolecular Polymer by Ionic Cluster‐Enhanced Iron‐Carboxylate Complexes

“…[1] To realize selfhealing properties, some strategies have been developed, especially using dynamic reversible noncovalent transformations to induce the reformation of damaged interfaces. [2][3][4][5][6][7] Taking advantage of the supramolecular toolbox that is, Hbonds, [2] host-guest combinations, [3] metal-ligand interactions, [4] ionic bonds, [5] dynamic covalent bonds, [6] dipoledipole interactions, [7] and even van der Waals force, [1e] have shown to be versatile features in the design of self-healing gels and polymers. However, there remain some very challenging issues facing the design of a self-healing supramolecular network: i) The introduction of weak but reversible noncovalent bonds into the network usually decreases significantly the stiffness of the network, leading to a self-healing but soft network; ii) The introduction of noncovalent bonds, especially based on hierarchical multi-component systems often requires complex synthetic procedures increasing material costs; iii) Many self-healing polymers contain or involve external solvents to support the supramolecular recognition processes, while developing self-healable dry polymers is more preferable for industrial application.…”

“…However, there remain some very challenging issues facing the design of a self-healing supramolecular network: i) The introduction of weak but reversible noncovalent bonds into the network usually decreases significantly the stiffness of the network, leading to a self-healing but soft network; ii) The introduction of noncovalent bonds, especially based on hierarchical multi-component systems often requires complex synthetic procedures increasing material costs; iii) Many self-healing polymers contain or involve external solvents to support the supramolecular recognition processes, while developing self-healable dry polymers is more preferable for industrial application. [1,2,8] Very recently, our lab developed an unprecedented supramolecular polymer using the natural small molecule, [8] thioctic acid (TA), as the main feedstock. A crosslinked solid polymer was obtained by a facile co-mixing method of molten TA liquid, 1,3-diisopropenylbenzene (DIB) and minimal FeCl 3 , involving no external solvent.…”

Mechano-responsive hydrogen-bonding array of thermoplastic polyurethane elastomer captures both strength and self-healing

“…According to the Ashby plot of UTS versus self-healing temperature for recently reported elastomers, previous tensile strengths did not exceed 20 MPa without the aid of light or a temperature above 40 °C ( Supplementary Fig. 7 and Supplementary Table 3) 9, [21][22][23][24][34][35][36][37][38][39][40]42,43,47 .…”

“…However, the trade-off between mechanical and healing performance is the biggest hurdle that these materials face and need to overcome. The high chain rigidity, entanglement, and crystallinity required for mechanical strength con ict with the high diffusibility and exchange of dynamic bonds required for repairing damage [21][22][23][24] . Consequently, materials that autonomously heal at ambient temperature exhibit mechanical performance that is unsatisfactory for industrial commercialization.…”