Chen Jiaoyang, Wang Dong, Fu Jiajun
School of Chemistry and Chemical Engineering, Nanjing University of Science and Technology, Nanjing, 210094, P. R. China.
School of Chemistry and Chemical Engineering, Huangshan University, Huangshan, Anhui, 245041, P. R. China.
Adv Mater. 2025 Jul 30:e07548. doi: 10.1002/adma.202507548.
Stiff yet room-temperature self-healing polymers are designed using molecularly engineered hydrogen bonds (H-bonds). However, they often suffer from high brittleness, moisture sensitivity, and limited functionality. To overcome these challenges, high-performance biomimetic nanocomposites inspired by inverse nacre structures are developed. A layered boron nitride nanosheet (BNNSs) skeleton is embedded within a previously synthesized room-temperature self-healing glassy polyurethane network, leveraging a solvent exchange-induced self-assembly strategy. This approach resolved the problem of BNNSs agglomeration and reconstructed robust yet dynamic noncovalent interfacial interactions, maximizing the reinforcing and toughening effects of BNNSs. Consequently, the nanocomposite exhibited significant mechanical enhancements, including 6.6-fold, 14.4-fold, 490-fold, and 35.7-fold increases in flexural modulus, strength, toughness, and fracture toughness, respectively, achieving a balance between stiffness and toughness. Furthermore, the nanocomposite retained room-temperature self-healing properties through the secondary relaxation of H-bonds. The impermeability of BNNSs effectively shielded H-bonds from moisture, fundamentally altering the hygroscopic nature of self-healing glassy polyurethanes. Additionally, the highly oriented and interconnected BNNSs skeleton endowed the nanocomposite with an in-plane thermal conductivity of up to 11.54 W m K, making it a promising candidate for next-generation high-performance intelligent thermal interface materials.
利用分子工程氢键（H键）设计出了坚硬但室温下可自愈合的聚合物。然而，它们常常具有高脆性、对湿度敏感以及功能有限等问题。为了克服这些挑战，开发了受反向珍珠母结构启发的高性能仿生纳米复合材料。通过溶剂交换诱导的自组装策略，将层状氮化硼纳米片（BNNSs）骨架嵌入到先前合成的室温自愈合玻璃态聚氨酯网络中。这种方法解决了BNNSs团聚的问题，并重建了强大而动态的非共价界面相互作用，使BNNSs的增强和增韧效果最大化。因此，该纳米复合材料表现出显著的力学增强，弯曲模量、强度、韧性和断裂韧性分别提高了6.6倍、14.4倍、490倍和35.7倍，实现了刚度和韧性之间的平衡。此外，该纳米复合材料通过H键的二次弛豫保留了室温自愈合性能。BNNSs的不透性有效地保护了H键不受水分影响，从根本上改变了自愈合玻璃态聚氨酯的吸湿特性。此外，高度取向且相互连接的BNNSs骨架赋予了该纳米复合材料高达11.54 W m K的面内热导率，使其成为下一代高性能智能热界面材料的有前途的候选材料。
