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.

For the first time, mesoporous Fe3O4@ZnO sphere decorated graphene (GN-pFe3O4@ZnO) composites with uniform size, considerable porosity, high magnetization and extraordinary electromagnetic (EM) wave absorption properties were synthesized by a simple and efficient three-step method. Structure and morphology details were characterized by X-ray diffraction, transmission electron microscopy, high-resolution electron microscopy and field-emission scanning electron microscopy. Electron microscopy images reveal that pFe3O4@ZnO spheres with obvious porous and core-shell structures are uniformly coated on both sides of the GN sheets without significant numbers of vacancies or apparent aggregation. EM wave absorption properties of epoxy containing 30 wt% GN-pFe3O4@ZnO were investigated at room temperature in the frequency region of 0.2-18 GHz. The absorption bandwidth with reflection loss (RL) values less than -10 dB is up to 11.4 GHz, and the minimal RL is almost -40 dB. The intrinsic physical and chemical properties of the materials, the synergy of Fe3O4 and ZnO, and particularly the unique multi-interfaces are fundamental to the enhancement of EM absorption properties. The as-prepared GN-pFe3O4@ZnO composites are shown to be lightweight, have strong absorption, and broad frequency bandwidth EM absorbers.

Self-healing polymers with microphase-separated structure are plagued with inferior self-healing efficiency at room temperature due to a lack of dynamic interactions in hard domains. Herein, we describe a novel strategy of multiphase active hydrogen bonds (H-bonds), toward realizing fast and efficient self-healing at room temperature, even under harsh conditions. The core conception is to incorporate thiourea moieties into microphase-separated polyurea network to form multistrength H-bonds, which destroy the crystallization of hard domains and, at the same time, insert the dynamic reversible H-bonds in both hard and soft segments, accounting for the surprisingly self-healing performances. The synthesized polymeric material, poly­(dimethylsiloxane)–4,4′-methylenebis­(phenyl isocyanate)–1,1′-thiocarbonyldiimidazole, completely recovers all of the mechanical properties within 4 h at room temperature after rupture. Significantly, self-healing process can also take place at low temperature (restoration with an 85% efficiency in 48 h at −20 °C) or in the water (restoration with a 95% efficiency in 4 h). Depending on the cleavage/reformation of multiphase H-bonds, the material exhibits unprecedented ultrastrechability and notch-insensitiveness. It can be stretched up to 31 500% without fracture and reach a notch-insensitive stretching of up to 18 000%. These exceptional characteristics inspired us to fabricate highly stretchable self-healable underwater conductor and protective self-healing film for suppressing shuttling of polysulfides and preventing crack propagation in S cathode, which provide the pathway for applications in underwater electronic devices or advanced Li–S batteries.

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