Room‐Temperature Self‐Healing Soft Composite Network with Unprecedented Crack Propagation Resistance Enabled by a Supramolecular Assembled Lamellar Structure

Abstract

Soft self-healing materials are compelling candidates for stretchable devices because of their excellent compliance, extensibility, and self-restorability. However, most existing soft self-healing polymers suffer from crack propagation and irreversible fatigue failure due to easy breakage of their dynamic amorphous, low-energy polymer networks. Herein, inspired by distinct structure-property relationship of biological tissues, a supramolecular interfacial assembly strategy of preparing soft self-healing composites with unprecedented crack propagation resistance is proposed by structurally engineering preferentially aligned lamellar structures within a dynamic and superstretchable poly(urea-ureathane) matrix (which is elongated to 24 750× its original length). Such a design affords a world-record fracture energy (501.6 kJ m −2 ), ultrahigh fatigue threshold (4064.1 J m −2 ), and outstanding elastic restorability (dimensional recovery from 13 times elongation), and preserving low modulus (1.2 MPa), high stretchability (3200%), and high room-temperature self-healing efficiency (97%). Thereby, the resultant composite represents the best of its kind and even surpasses most biological tissues. The lamellar 2D transition-metal carbide/carbonitride (MXene) structure also leads to a relatively high in-plane thermal conductivity, enabling composites as stretchable thermoconductive skins applied in joints of robotics to thermal dissipation. The present work illustrates a viable approach how autonomous self-healing, crack tolerance, and fatigue resistance can be merged in future material design.

A self-assembled CuS–MXene bridge for hole-boosting 10.51%-efficiency all-inorganic tri-brominated perovskite solar cells

“…5c) and the high thermal conductivity of MXene. 45 Furthermore, the S⋯Pb interaction between CuS and CsPbBr 3 restrains the migration of lead ions and therefore also improves the environmental tolerance.…”

Oxygen-co-Thermal Driver for Constructing Integrated Anisotropic Hydrogels with Programmable Shape Deformation, Superior Self-Healing, and Mechanical Performance

“…As shown in Figure b, the fracture strain and stress at break of the original Pdmda 4 hydrogel were 406.54% and 1.02 MPa, while those of the damaged hydrogel after 30 min of repair were 286.41% and 0.78 MPa, with a healing efficiency of 76%. This superior self-healing property is mainly attributed to the presence of reversible multiple forces (two different electrostatic interactions and hydrogen bonding) between AMPS, AA, and DMAEMA units of the PDMDA polymer chain. , Specifically, once the hydrogels were disrupted, the chain segments migrated and gradually diffused to the fracture interface, , at which time the hydrogen bonds between a large number of sulfonic acid groups, protonated amines and carboxylic acid groups were rapidly reconstructed, followed by the electrostatic interactions among those three units that were also gradually reconstructed within a few minutes at room temperature, and this process allowed the hydrogels to heal autonomously and rapidly (Figures c and S5). Moreover, the remarkable self-healing ability of this hydrogel was also verified by the electrical conductivity and mechanical capacity of the hydrogels before and after healing.…”

Self-healing polymers through hydrogen-bond cross-linking: synthesis and electronic applications

“…The feasibility of the bionic structure design can be observed in the research by Fu's group. 101,103,104 For example, some biological tissues, such as the reticular layer of the human skin dermis, provide promising ideas for researchers to the address conflict between the selfhealability and fatigue resistance of SHPs. Employing UPy supramolecular motifs as phase regulators, they proposed a molecular engineering strategy that transforms inherently fragile materials with an island-like structure into soft selfhealable elastic materials with a bicontinuous nanophase separation structure.…”

“…3.3.4 Others. Based on their exceptional mechanical performance and self-healable features, H-bonding-based SHPs have also been employed as a multifunctional electronic device platform, 193 matrix of thermal interface materials, 104,194 and substrate for stretchable electrodes. 50,79,86 For example, Bao and co-workers 50 reported the fabrication of a stretchable and autonomous self-healing electrode using tough and waterinsensitive SHPs as the encapsulation and supporting layer, which exhibited high stretchability (B500%) with stable (100 cycles) and reversible low resistance.…”