Tough and Degradable Self-Healing Elastomer from Synergistic Soft–Hard Segments Design for Biomechano-Robust Artificial Skin

Abstract

Increasing biomechanical applications of skin-inspired devices raise higher requirements for the skin-bionic robustness and environmental compatibility of elastomers. Here, a tough and degradable self-healing elastomer (TDSE) is developed by a synergistic soft–hard segments design. The polyester/polyether copolymer is introduced in soft segments to endow TDSE with flexibility and degradability. The two isomeric diamines are regulated in hard segments for elevating the toughness and fracture energy to 82.38 MJ/m3 and 43299 J/m2 and autonomous self-healing ability with 93% efficiency in 7 h for the TDSE. Employing TDSE and ionic liquid, a biomechano-robust artificial skin (BA-skin) is constructed with a stretch-insensitive mechanosensation capability during 50% cyclic stretching. The BA-skin has high biomechano-robustness to bear tear damage and good environmental compatibility with total decomposability in a lipase solution. This work provides a molecular design guideline for high-performance skin-bionic elastomers for applications in skin-inspired devices.

Structures and properties of newly synthesized semi-aromatic polyamide thermoplastic elastomers

“…Compared to TPA, IPA has a lower structural symmetry with more characteristic peaks of hydrogen in the hydrogen nuclear magnetic resonance ( 1 H NMR) spectra, which leads to weaker intermolecular force. 47 Thus, multistrength H-bonds will be obtained, affecting crystallization capacity. TPAE-0 has a slower crystallization rate and forms imperfect crystals during the subsequent heating process.…”

“…For example, Zhang et al constructed multi-strength hydrogen-bond (H-bond) units from two isomeric diamines and employed them to elevate the elastic recovery, toughness, and fracture energy of a self-healing elastomer. 47 Song et al obtained self-healing materials with super toughness and high tensile strength due to the incorporation of hierarchical hydrogen bonds. 48…”

“…For example, Zhang et al constructed multi-strength hydrogen-bond (H-bond) units from two isomeric diamines and employed them to elevate the elastic recovery, toughness, and fracture energy of a selfhealing elastomer. 47 Song et al obtained self-healing materials with super toughness and high tensile strength due to the incorporation of hierarchical hydrogen bonds. 48 Herein, a semi-aromatic polyamide based thermoplastic elastomer with a distinct microphase-separated morphology containing both strong and weak H-bond units was fabricated via melt polycondensation without any organic solvent, as shown in Schemes 1 and 2.…”

Functional Epoxy Elastomer Integrating Self-Healing Capability and Degradability for a Flexible Stretchable Strain Sensor

“…However, the elastomer was only degraded in a specific mixed organic solution of dichloromethane with excess trifluoroacetic acid, O -ethylhydroxylamine, and benzaldehyde. To date, it is still a great challenge to prepare self-healing and degradable elastomers with excellent mechanical performances for high-performance and environmentally friendly flexible strain sensors. , …”

“…To date, it is still a great challenge to prepare self-healing and degradable elastomers with excellent mechanical performances for high-performance and environmentally friendly flexible strain sensors. 37,38 In this work, a series of functional epoxy elastomers with self-healing capability and degradability for flexible strain sensors were synthesized with carboxyl-terminated poly-(ethylene glycol), 2,2′-dithiodibenzoic acid, and 1,4-butanediol diglycidyl ether as monomers and bio-based epoxidized soybean oil as the crosslinker. Thanks to the synergistic healing effect of the hydrogen bonds and disulfide bonds, the elastomer exhibited good self-healing performance with a healing efficiency of 92.5% at 80 °C for 24 h. In addition, the generated β-hydroxyl ester bonds endowed the elastomer with degradability in alkaline solution.…”