Flexible and integrated sensing platform of acoustic waves and metamaterials based on polyimide coated woven carbon fibers

Versatile, in situ sensing and continuous monitoring capabilities are critically needed, but challenging, for components made of solid woven carbon fibers in aerospace, electronics, and medical applications. In this work, we proposed a unique concept of integrated sensing technology on woven carbon fibers through integration of thin-film surface acoustic wave (SAW) technology and electromagnetic metamaterials, with capabilities of noninvasive, in situ, and continuous monitoring of environmental parameters and biomolecules wirelessly. First, we fabricated composite materials using a three-layer composite design, in which the woven carbon fiber cloth was first coated with a polyimide (PI) layer followed by a layer of ZnO film. Integrated SAW and metamaterials devices were then fabricated on this composite structure. The temperature of the functional area of the device could be controlled precisely using the SAW devices, which could provide a proper incubation environment for biosampling processes. As an ultraviolet light sensor, the SAW device could achieve a good sensitivity of 56.86 ppm/(mW/cm2). On the same integrated platform, an electromagnetic resonator based on the metamaterials was demonstrated to work as a glucose concentration monitor with a sensitivity of 0.34 MHz/(mg/dL).