Tough and transparent polyurethane networks with self-healing capability at mild temperature conditions were successfully prepared in a 1-pot procedure. The self-healing ability of synthesized polyurethane comes from the covalent disulfide metathesis and non-covalent H-bonding. The mechanical testing indicates that disulfide metathesis reforms the covalent bonds on a longer time scale, while H-bonding gives rise to a healing efficiency of around 46% in the early healing processing. The compromise between mechanical performance and healing capability is reached by tailoring the concentration of disulfide. The tensile strength of the sample with 100% self-heal efficiency can get to 5.01 MPa, which can be explained by higher mobility of polymer chain under ambient temperature from creep testing.
Magnetic actuators, which use magnetic effects for actuation, are very useful in many areas, such as electrical equipment, soft robots, and medical instruments. However, they inevitably suffer damage during long-term use, leading to mechanical failure. Introduction of the self-healing concept can solve this problem to a certain extent and extend their service life. Herein, a room-temperature self-healing magnetic nanocomposite is obtained using a simple, efficient, and environmental-friendly strategy. In the authors' design, soft poly(dimethylsiloxane) (PDMS) polymeric materials are chosen as the matrix, and Fe 3 O 4 nanoparticles are utilized as a functional magnetic nanofiller to obtain a new magnetic nanocomposite. By balancing the self-healing property and mechanical performance, the optimal content of magnetic filler is determined to be 15 wt%. The optimized sample exhibits an ultimate tensile strength (0.44 MPa), a high tensile strain (400%), and an excellent self-healing efficiency (62.2% mechanical recovery of fracture strength) at 25 °C for 30 min. Furthermore, this composite material shows an excellent and healable magnetic actuation performance. This new nanocomposite provides great potential for the magnetic actuation application.
Ying Jiang,Kai Chen,Jinping He,Yuxue Sun,Xiaorong Zhang,Xiaoxing Yang,Haiming Xie,Jun Liu
Composite solid electrolytes (CSEs), which combine the advantages of solid polymer electrolytes and inorganic solid electrolytes, are considered to be promising electrolytes for all-solid-state lithium metal batteries. However, the current CSEs suffer from defects such as poor inorganic/organic interface compatibility, lithium dendrite growth, and easy damage of electrolyte membrane, which hinder the practical application of CSEs. Herein, a CSE (PBHL@LLZTO@DDB) with polyurethane (PBHL) as the polymer matrix and Li 6.4 La 3 Zr 1.4 Ta 0.6 O 12 (LLZTO) modified by silane coupling agent (DDB) as inorganic fillers (LLZTO@DDB) has been prepared. Disulfide bond exchange reactions between PBHL and LLZTO@DDB enable PBHL@LLZTO@DDB to form a dynamic three-dimensional (3D) inorganic/organic hybrid network, which promotes the uniform dispersion of LLZTO in PBHL@LLZTO@DDB, improves the Li + conductivity (1.24 ± 0.08 × 10 −4 S cm −1 at 30 ℃), and broadens the electrochemical stability window (5.16 V vs. Li + /Li). Moreover, a combination of hydrogen bonds and disulfide bonds endows PBHL@LLZTO@DDB with excellent self-healing properties. As such, both all-solid-state symmetric and full cells exhibit excellent cycle performance at ambient temperature. More importantly, the healed PBHL@LLZTO@DDB can almost completely restore its original electrochemical properties, indicating its application potential in flexible electronic products.
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