Fiber-Reinforced Flexible Self-Healing Strain Sensor with Failure-Improving Sensitivity Recovery

Titelangaben

Milkin, Pavel ; Pavale, Shubham ; Vohr Soreño, Zhander ; Ionov, Leonid:
Fiber-Reinforced Flexible Self-Healing Strain Sensor with Failure-Improving Sensitivity Recovery.
In: ACS Applied Materials & Interfaces. Bd. 16 (2024) Heft 44 . - S. 61050-61060.
ISSN 1944-8252
DOI: https://doi.org/10.1021/acsami.4c14295

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Abstract

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.