Guangdong Provincial Key Laboratory of Materials for High Density Electronic Packaging, Shenzhen Institutes of Advanced Technology, Chinese Academy of Sciences , Shenzhen 518055, China.
Nano Science and Technology Institute, University of Science and Technology of China (USTC) , Suzhou 215123, China.
ACS Appl Mater Interfaces. 2017 Jan 25;9(3):3040-3049. doi: 10.1021/acsami.6b15476. Epub 2017 Jan 13.
The continuous evolution toward flexible electronics with mechanical robust property and restoring structure simultaneously places high demand on a set of polymeric material substrate. Herein, we describe a composite material composed of a polyurethane based on Diels-Alder chemistry (PU-DA) covalently linked with functionalized graphene nanosheets (FGNS), which shows mechanical robust and infrared (IR) laser self-healing properties at ambient conditions and is therefore suitable for flexible substrate applications. The mechanical strength can be tuned by varying the amount of FGNS and breaking strength can reach as high as 36 MPa with only 0.5 wt % FGNS loading. On rupture, the initial mechanical properties are restored with more than 96% healing efficiency after 1 min irradiation time by 980 nm IR laser. Especially, this is the highest value of healing efficiency reported in the self-healable materials based on DA chemistry systems until now, and the composite exhibits a high volume resistivity up to 5.6 × 10 Ω·cm even the loading of FGNS increased to 1.0 wt %. Moreover, the conductivity of the broken electric circuit which was fabricated by silver paste drop-cast on the healable composite substrate was completely recovered via IR laser irradiating bottom substrate mimicking human skin. These results demonstrate that the FGNS-PU-DA nanocomposite can be used as self-healing flexible substrate for the next generation of intelligent flexible electronics.
具有机械鲁棒性和恢复结构的柔性电子产品的不断发展，对一系列聚合物材料衬底提出了很高的要求。在此，我们描述了一种由基于 Diels-Alder 化学的聚氨酯（PU-DA）与功能化石墨烯纳米片（FGNS）共价键合而成的复合材料，该复合材料在环境条件下表现出机械鲁棒性和红外（IR）激光自修复性能，因此适用于柔性衬底应用。通过改变 FGNS 的用量可以调节机械强度，当 FGNS 的用量仅为 0.5wt%时，断裂强度可高达 36MPa。在断裂时，通过 980nmIR 激光照射 1 分钟，初始机械性能可恢复 96%以上，具有超过 96%的修复效率。特别是，这是迄今为止基于 DA 化学体系的自修复材料中报告的最高修复效率值，并且即使 FGNS 的加载量增加到 1.0wt%，复合材料仍具有高达 5.6×10Ω·cm 的高体积电阻率。此外，通过在可修复复合衬底上滴铸银浆来制备的断裂电路的导电性可以通过 IR 激光照射底层衬底完全恢复，模拟人类皮肤。这些结果表明，FGNS-PU-DA 纳米复合材料可用作下一代智能柔性电子产品的自修复柔性衬底。
