Flexible strain sensors fabricated with carbon nano-tube and carbon nano-fiber composite thin films

This paper presents the fabrication of 3 × 3 flexible strain sensor arrays using conductive polymer solutions with fillers including carbon nano-fibers and multi-walled carbon nano-tubes. The strain sensor arrays were made on polyurethane substrates using patterned surface treatment and the tilted-drop process. Atmospheric plasma was used to enhance or reduce the surface energy in specific areas for patterned surface treatment. The performance of fabricated strain sensors made using conductive polymer solutions with different ingredients was investigated. The measured gauge factors were in the 0.34 to 7.98 range for the strain of 3–7%. Under a bending test exceeding 50 times at a 150° angle, sensor damage was not observed. The demonstrated fabrication method is capable of producing conductive polymer sensors with complex designs, high reliability and is suitable for mass production.