Department of Health Technology, Technical University of Denmark, 2800 Kgs. Lyngby, Denmark.
Department of Mechanical Engineering, Technical University of Denmark, 2800 Kgs. Lyngby, Denmark.
ACS Nano. 2021 Jun 22;15(6):9531-9549. doi: 10.1021/acsnano.0c09204. Epub 2021 May 13.
Soft and electrically active materials are currently being utilized for intelligent systems, including electronic skin, cybernetics, soft robotics, and wearable devices. However, fabricating materials that fulfill the complex requirements of such advanced applications remains a challenge. These attributes include electronic, adhesive, self-healing, flexible, moldable, printable, and strong mechanical properties. Inspired by the recent interest in transforming monofunctional materials into multifunctional ones through nanoreinforcement and mussel-inspired chemistry, we have designed a simple two-step methodology based on halloysite nanotube (HNT) and polydopamine (PDA) to address the grand challenges in the field. In brief, HNTs were coated with PDA and embedded within a poly(vinyl alcohol) (PVA)-based polymeric matrix in combination with ferric ions (Fe). The final composite displayed a 3-fold increase in electrical conductivity, a 20-fold increase in mechanical stiffness, and a 7-fold increase in energy dissipation in comparison to their nonfunctional counterparts, which arose from a combination of nanotube alignment and mussel-inspired chemistry. Moreover, the developed composite could elongate up to 30000% of its original length, maintain its electrical properties after 600% strain, self-heal within seconds (both electrically and mechanically), and display strain-sensitivity. Finally, it was 3D-printable and thus amenable for engineering of customized wearable electronics.
软质和电活性材料目前被用于智能系统，包括电子皮肤、控制论、软体机器人和可穿戴设备。然而，制造满足这些先进应用复杂要求的材料仍然是一个挑战。这些属性包括电子、粘性、自修复、灵活、可模塑、可打印和强大的机械性能。受最近将多功能材料转化为多功能材料的兴趣的启发，我们通过纳米增强和贻贝启发的化学设计了一种简单的两步法，以解决该领域的重大挑战。简而言之，将 PDA 涂覆在 halloysite 纳米管 (HNT) 上，并将其与铁离子 (Fe) 一起嵌入到基于聚乙烯醇 (PVA) 的聚合物基质中。与非功能性对应物相比，最终的复合材料的导电性提高了 3 倍，机械刚度提高了 20 倍，能量耗散提高了 7 倍，这是由于纳米管的排列和贻贝启发的化学的共同作用。此外，所开发的复合材料可以伸长到其原始长度的 30000%，在 600%的应变后保持其电性能，在几秒钟内（电和机械）自我修复，并具有应变敏感性。最后，它是可 3D 打印的，因此适用于定制可穿戴电子产品的工程设计。
