A fast-healing and high-performance metallosupramolecular elastomer based on pyridine-Cu coordination

Abstract

Elastomers easily undergo a catastrophic failure as soon as a crack is introduced by mechanical damage. Thus, it is extremely important for elastomers to possess fast healing ability, which enables the quick reparation of cracks. However, developing elastomers with fast self-healing ability and high mechanical strength is highly challenging. Herein, we fabricate a metallosupramolecular elastomer by facilely introducing pyridine-Cu coordination into a copolymer of ethyl acrylate and vinyl pyridine. Interestingly, the pyridine-Cu coordination has a strong photothermal effect, which readily increases the sample temperature to 60°C in 30 s under near-infrared light. At this temperature, the sticky reptation modes are activated and thus serve as the driving force for network reorganization and fast self-healing of the metallosupramolecular elastomer. Albeit with a tensile strength of 10 MPa, the scratched and completely fractured samples can be healed within 2 min and 3 h, respectively. Moreover, during the damage and healing processes, the break and reformation of the coordination bonds can be tracked through laser confocal micro-Raman spectroscopy. This provides a microscopic methodology to monitor the bond-level healing kinetics of metallosupramolecular polymers.

Effect of Counterions on the Physicomechanical Properties of Copper–Nitrogen-Coordinated Metallosupramolecular Elastomers

“…The stable photothermal effect and dynamic supramolecular network of BA-VI-CuX n further support infrared photohealing applications. ,,− To prove this, the BA-VI-CuX n samples are precut to create scratches of 30–50 μm depth by a single-sided blade, and then the scratches are placed under a 650 nm laser to heal for 0.5, 1, and 2 min (shown in Figures e and S12). The tensile strength of the scratched BA-VI-CuX n decreases significantly to 14% of the original value; however, it can be quickly healed to 90% after 2 min of laser irradiation.…”

“…The number average molecular weight ( M n ) of BA-VI measured by gel permeation chromatography (GPC) is 170.0 kg/mol, which is higher than the reported critical entanglement molecular weight (65.0 kg/mol) of polybutylacrylate, indicating the presence of entanglements between the BA-VI molecular chains. BA-VI is dissolved in ethyl acetate, to which a methanol solution containing CuX n is slowly added, wherein the molar ratio of copper ions and imidazole groups is controlled to be 1:12 . The mixture is then cast into films, resulting in the metallosupramolecular elastomers BA-VI-CuX n .…”

“…BA-VI is dissolved in ethyl acetate, to which a methanol solution containing CuX n is slowly added, wherein the molar ratio of copper ions and imidazole groups is controlled to be 1:12. 38 The mixture is then cast into films, resulting in the metallosupramolecular elastomers BA-VI-CuX n . CuX n includes CuCl 2 , CuBr 2 , or Cu(NO 3 ) 2 .…”

Biologically Derived Metal–Cysteine Coordination Complexes Crosslink Carboxylated Nitrile Rubber and Enable Room Temperature Self-Healing, Stretchability, and Recyclability

“…51 Herein, we have developed a novel technique that advantages adaptability in synthesizing a reactive metal−amino complex (Zn/Ni-cysteine complexes), which can use as a coordination crosslinking agent in rubber materials. In comparison to the pure L-cysteine-cured product, the naturally occurring metal− cysteine coordination complexes crosslinking XNBR rubber displayed excellent stretchability, good robustness, recyclability, and outstanding self-healing performance at room temperature for 24 h. This investigation contrasts physical crosslinking (metal−ligand networks) and covalent interaction (disulfide linkage), as well as the impact of room temperature self-healing efficiency, 52,53 stretchability, recyclability, and mechanical characteristics of rubbery materials. Our naturally occurring zinc−cysteine coordination complex crosslinked selfhealing materials have a healing efficiency of up to 89.5% after 24 h of room temperature, a tensile strength of 3.8 MPa, and good stretchability.…”

Current Self-Healing Binders for Energetic Composite Material Applications

“…In addition, the presence of functional metal ions and/or ligands can stimulate various functions, so it is easy to find valuable potential applications in various technical fields. For example, pyridine–copper coordination has a strong photothermal effect, which can rapidly raise the temperature of the sample to 60 °C under near-infrared light irradiation [ 115 ]. At this time, the sticky reptation modes of supramolecular polymer are activated, which drives network reorganization and rapid self-repair.…”