Vascular smooth muscle-inspired architecture enables soft yet tough self-healing materials for durable capacitive strain-sensor

Abstract

Catastrophically mechanical failure of soft self-healing materials is unavoidable due to their inherently poor resistance to crack propagation. Here, with a model system, i.e., soft self-healing polyurea, we present a biomimetic strategy of surpassing trade-off between soft self-healing and high fracture toughness, enabling the conversion of soft and weak into soft yet tough self-healing material. Such an achievement is inspired by vascular smooth muscles, where core-shell structured Galinstan micro-droplets are introduced through molecularly interfacial metal-coordinated assembly, resulting in an increased crack-resistant strain and fracture toughness of 12.2 and 34.9 times without sacrificing softness. The obtained fracture toughness is up to 111.16 ± 8.76 kJ/m2, even higher than that of Al and Zn alloys. Moreover, the resultant composite delivers fast self-healing kinetics (1 min) upon local near-infrared irradiation, and possesses ultra-high dielectric constants (~14.57), thus being able to be fabricated into sensitive and self-healing capacitive strain-sensors tolerant towards cracks potentially evolved in service.

Extremely strengthening fatigue resistance, elastic restorability and thermodynamic stability of a soft transparent self-healing network based on a dynamic molecular confinement-induced bioinspired nanostructure

“…SHPU-WNS was a typical elastomer with a relatively low Young's modulus of 0.60 ± 0.09 MPa, comparable to that of other soft self-healing materials. 4 However, the tensile stress and tensile strain of SHPU-WNS were relatively poor, which were 0.63 ± 0.02 MPa and 970% ± 50%, respectively, thereby leading to a comparatively low toughness of 3.6 ± 0.5 MJ m −3 (Fig. S9 and Table S1, ESI†).…”

“…, hydrogen bonds, ionic bonds, and metal–ligand interactions). 4–6 However, the inherently weak bonding strengths of these interactions usually result in low fatigue thresholds ( Γ 0 ) of the resulting polymers, making them highly susceptible to crack initiation during repeated loadings. 7,8 So far molecular energy dissipation mechanisms based on sacrificial bonds, either covalent bonds or non-covalent bonds, 9,10 have been proposed to make soft self-healing materials resist crack propagation under monotonic loading ( i.e.…”

Crosslinking of Bacterial Cellulose toward Fabricating Ultrastretchable Hydrogels for Multiple Sensing with High Sensitivity

“…44 The fracture strain level could decrease sharply once the cracks existed in the PAM matrix due to the quick crack propagation. 45 The fracture behavior of notched samples is evaluated here, as shown in Figures 5a,b and S4 of Supporting Information. The tensile traces of the neat PAM hydrogel and ionic hydrogel are shown in Figure 5c.…”

Intrinsic Self-Healing Chemistry for Next-Generation Flexible Energy Storage Devices

“…In nature, many organisms have the ability to repair damage spontaneously, which is an important property for extending the lifespan of an organism. Similarly, some functional materials also have the function of self-healing, which are called self-healing materials, and they can repair the matrix damage caused by mechanical work [ 29 – 33 ]. Therefore, introducing smart self-healing materials into flexible batteries or capacitors is considered to be a very promising means to resist mechanical damage and prolong their life [ 21 , 29 , 34 – 36 ].…”