Transparent, Mechanically Strong, Extremely Tough, Self‐Recoverable, Healable Supramolecular Elastomers Facilely Fabricated via Dynamic Hard Domains Design for Multifunctional Applications

Abstract

The design and synthesis of supramolecular self‐healing polymers with high healing efficiency and excellent integrated mechanical properties is challenging due to conflicting attributes of dynamic self‐healing and mechanical properties. Herein, this study introduces a design concept, that is, “dynamic hard domains,” to balance self‐healing performance, mechanical strength, elastic recovery, and at the same time obtain extreme toughness. The essential features of the dynamic hard domains include: (i) a noncrystallized and loose structure, (ii) low binding energy and high mobility, and (iii) sequential dissociation and rapid rearrangement. Based on this strategy, a simple one‐step polycondensation route is reported to synthesize a transparent polyurethane‐urea supramolecular elastomer (PPGTD‐IDA), which successfully combines decent mechanical strength, extreme toughness, outstanding notch‐sensitiveness, self‐recoverability, and room‐temperature self‐healing. Upon rupture, the PPGTD‐IDA completely restores the mechanical properties within 48 h. Furthermore, the results demonstrate repeatable healing of mechanical properties and prominent antiaging healability. Taking advantages of merits of PPGTD‐IDA, it can be utilized for fabricating impact‐resistant materials for protection of aluminum alloys as well as stretchable and self‐healing conductors, which exhibits unique characteristics such as stable conductivity during stretching (even after healing or with notch), and automatic elimination of the notch during stretching/releasing cycles.

Healable, Recyclable, and Mechanically Tough Polyurethane Elastomers with Exceptional Damage Tolerance

“…Damage-tolerant elastomers cross-linked with dynamic interactions can be healable but usually exhibit low strength and fracture energy. [6,14,27,31] The reported healable damage-tolerant elastomers can achieve the highest fracture energy of 42.6 kJ m −2 , which is much lower than that of damage-tolerant elastomers without healing. [31] Therefore, a sophisticated design is required to simultaneously combine high mechanical strength and toughness, excellent damage tolerance, and healable/recyclable capacities in one synthetic elastomer.…”

“…[6,14,27,31] The reported healable damage-tolerant elastomers can achieve the highest fracture energy of 42.6 kJ m −2 , which is much lower than that of damage-tolerant elastomers without healing. [31] Therefore, a sophisticated design is required to simultaneously combine high mechanical strength and toughness, excellent damage tolerance, and healable/recyclable capacities in one synthetic elastomer. In this study, we fabricated healable and recyclable polyurethane (PU) elastomers with a tensile strength of ≈52.4 MPa, a toughness of ≈363.8 MJ m −3 , and an exceptional fracture energy of ≈192.9 kJ m −2 by designing dynamic hierarchical domains within multiblock polymers of poly(dimethylsiloxane) (PDMS)/ polycaprolactone (PCL).…”

“…[6,21,23,24] The introduction of noncovalent interactions and dynamic covalent bonds within the polymer chains provides a practical way for the fabrication of polymer materials with intrinsic healability and recyclability because these dynamic interactions can be reversibly broken and reformed. [2,[24][25][26][27][28][29][30][31][32] The major concern associated with healable/recyclable elastomers (and other polymer materials) is the mutual exclusion between mechanical strength and healable/recyclable capacity. [24,29,30] Elastomers with high mechanical strength have limited chain mobility, which severely hinders their healing and recycling process.…”

“…[3,34,35] In contrast, elastomers conferred with good damage tolerance can effectively prohibit the propagation of physical damage such as cuts and cracks to retain most of their mechanical properties. [31,36,37] Therefore, elastomers integrated with damage tolerance and healability are more effective than those solely integrated with healability in extending service life and enhancing reliability. The damage tolerance of elastomers or other kinds of polymer materials requires efficiently dissipating energy concentrated in the damaged regions.…”

The Essential Role of 1-Butyl-3-Methylimidazolium-Based Ionic Liquids in the Development of Transparent Silica-Filled Elastomer Systems

“…A variety of transparent and thermochromic materials have been reported in the literature [ 6 , 7 ]. Such materials have found applications in fields including biotechnology, electronic data storage, and temperature-sensitive coatings [ 8 , 9 ].…”