Periodically inlaid carbon fiber bundles in the surface of honeycomb woven fabric for fabrication of normal pressure sensor

Honeycomb woven fabric is a single-layer fabric with three-dimensional effect. The effect is attributed to the increased length of warp and weft floats from the center to the sides of a weave unit, resulting in an inverted pyramid space on surface and an internal closed space in fabric. In order to study the practical application of such fabrics, 12 honeycomb woven fabrics were fabricated by considering the type of weft yarns (PET FDYs/PET DTYs/carbon fibers) and weft density (60/80/100 yarns per inch). Physical properties, including air permeability, warmth retention, water absorption, vapor transfer and flexible rigidity, compressibility and tensile properties, were all investigated. In addition, the characteristics of as-made fabrics were explored as a flexible normal pressure sensor with the capacitive structure of carbon fiber bundles, including the sensitivity, hysteresis and repeatability. The results showed that the weft density and elastic yarns have a regular influence on the physical properties, and the carbon fibers increase the initial modulus remarkably. Besides, an excellent sensing performance of as-made fabric was noted to be a flexible pressure sensor. Demonstrations of such fabric sensor in detecting finger pressing and object placing were performed, and corresponding actions were noted for the output clear and effective capacitive signals.