Tough and Healable Elastomers via Dynamic Integrated Moiety Comprising Covalent and Noncovalent Interactions

Abstract

Elastomers that combined excellent mechanical performance and healability are essential to the advancement of stretchable electronics. However, the strength and toughness of healable elastomers tend to be mutually exclusive. Herein, a new strategy of the dynamic integrated moiety is developed to construct covalent and noncovalent cross-linked polyurethane (CNPU) elastomers. The covalent and noncovalent interactions synergistically enhance the overall mechanical properties of polyurethane elastomers such as tensile strength (48.8 MPa), toughness (282.9 MJ·m–3), stretchability (1740%), and healing efficiency (116%). Finally, elastic conductive wires are fabricated with high load capacity, stable electrical conductivity under static/dynamic stretching, and robust healability to demonstrate the potential use of CNPU elastomers in stretchable electronics.

Infrared Spectroscopic and Mechanical Analysis of Supramolecular Self-Healing in 3D Printable Urea Photoresins

“…Compared to extrusion 3D printing, VP-3DP is preferred to produce prints with high resolution and small feature size . Photoreactive resins for VP-3DP usually contain acrylated and methacrylated monomers and oligomers that undergo free radical polymerization and yield cross-linked thermosets. , During this process, the mobility and diffusion of the propagating chains change, and the composition and the distance in between cross-links vary throughout the network, and as a result, the 3D printed thermosets exhibit low toughness. , …”

“…3,4 During this process, the mobility and diffusion of the propagating chains change, and the composition and the distance in between cross-links vary throughout the network, and as a result, the 3D printed thermosets exhibit low toughness. 5,6 One of the main strategies to increase toughness in polymer networks is to include monomers and oligomers with sacrificial bonds to dissipate energy. 7−9 Because of their reversibility, noncovalent interactions can dissipate excess energy; increasing the mechanical strength of thermosets without sacrificing their elongation before failure.…”

A Photohealable Polyurethane with Superior Robustness and Healing Ratio

“…Many current healable polymers are based on supramolecular reversible interaction, − such as host–guest interaction, , metal–ligand coordination, ionic interaction, , and hydrogen bonding. , It has been revealed that supramolecular reversible interactions can effectively shorten the distance of the dynamic molecular segment, which favors a high healing ratio and efficient healing . For example, Kang and coworkers reported an efficient self-healing elastomer that can heal itself in 1.5 h through multistrength hydrogen bonding interactions.…”

“…In contrast, others, originating from the destruction and recombination of dynamic interactions, enable the repeated healing of polymer materials after being damaged. 16 Many current healable polymers are based on supramolecular reversible interaction, 17−21 such as host−guest interaction, 22,23 metal−ligand coordination, 24 ionic interaction, 25,26 and hydrogen bonding. 27,28 It has been revealed that supramolecular reversible interactions can effectively shorten the distance of the dynamic molecular segment, which favors a high healing ratio and efficient healing.…”

Self-Healing Strategies in Rubber Composites

“…Una de ellas ha sido el desarrollo de materiales compuestos elastoméricos, donde la carga cumpla una doble función: reforzante y como agente reparador [6][7][8]. Otra estrategia que despierta gran interés es la combinación de diferentes mecanismos de reparación, creando redes duales entrecruzadas donde se combinan interacciones no-covalentes, enlaces covalentes, o ambos [3,[9][10][11][12][13]. Los sistemas no-covalentes se caracterizan por tener una baja energía de enlace en comparación con los sistemas covalentes puros, por lo que suelen tener mayores eficiencias de reparación ya que esto facilita la restauración de los enlaces rotos incluso a temperatura ambiente.…”