Milkin Pavel, Pavale Shubham, Soreño Zhander Vohr, Ionov Leonid
Faculty of Engineering Sciences, University of Bayreuth, Ludwig Thoma Str. 36A, 95447 Bayreuth, Germany.
Bavarian Polymer Institute, University of Bayreuth, 95447 Bayreuth, Germany.
ACS Appl Mater Interfaces. 2024 Nov 6;16(44):61050-61060. doi: 10.1021/acsami.4c14295. Epub 2024 Oct 23.
In this work, we address the inherent limitations of porous, flexible, fibrous, and self-healing strain sensors. Specifically, we tackle issues such as the fatigue failure of carbon-fibrous materials and the long-term flow and low mechanical stability of self-healing materials. We achieve this by combining self-healing carbon/PBS blends with fibrous materials, creating a fiber-reinforced self-healing composite. The self-healing carbon/PBS blends provide strain sensitivity and the ability to recover after fatigue and impact failure, while the fibers prevent the long-term flow of material and the scattering of pieces during impact and fatigue failure within the elastic deformation regime, enabling shape recovery. We fabricated composite wearable strain sensors with a viscoelastic functional layer composed of two continuous phases: (i) a self-healing polymer-carbon blend and (ii) long electrospun fibers of commercial polyurethane. This setup also eliminates the other drawbacks of bulk materials, such as nonlinearity of volt-ampere characteristics, irreversibility of deformation, and a low working factor, and allows improvement of the working factor after failure and healing. Most importantly, we discovered that hindered self-healing, like in the case of the MWCNT/PBS system, enables improvement of sensor sensitivity after large strains and failure, which is due to partial failure of the network formed by conductive particles.
在这项工作中，我们解决了多孔、柔性、纤维状和自修复应变传感器的固有局限性。具体而言，我们解决了诸如碳纤维材料的疲劳失效以及自修复材料的长期流动和低机械稳定性等问题。我们通过将自修复碳/PBS共混物与纤维材料相结合来实现这一点，从而创建一种纤维增强自修复复合材料。自修复碳/PBS共混物提供应变敏感性以及在疲劳和冲击失效后恢复的能力，而纤维在弹性变形范围内可防止材料的长期流动以及冲击和疲劳失效期间碎片的散落，实现形状恢复。我们制造了具有粘弹性功能层的复合可穿戴应变传感器，该功能层由两个连续相组成：（i）自修复聚合物-碳共混物和（ii）商用聚氨酯的长电纺纤维。这种设置还消除了块状材料的其他缺点，如伏安特性的非线性、变形的不可逆性和低工作系数，并允许在失效和修复后提高工作系数。最重要的是，我们发现，如在MWCNT/PBS系统中那样的受阻自修复能够在大应变和失效后提高传感器的灵敏度，这是由于导电颗粒形成的网络发生了部分失效。
