Fabrication of self-assembly CNT flexible film and its piezoresistive sensing behaviors

Abstract

Strain sensors are essential for health monitoring of complex-shaped structures. Here, carbon nanotube thin films (CNTFS) with different double-layers were fabricated on a flexible polyethylene terephthalate substrate using layer-by-layer self-assembly technique, and their resistance behaviors and piezoresistive sensing performances were comprehensively conducted. Results show that the assembled layers of CNTFS are evenly and compactly deposited with about 7–15 μm, and the resistance decreases with the increase in the assembly layer number. The piezoresistive sensing behavior increases first and then decreases with the increase in the number of assembly layers along with compression or tension cyclic loading; the nine-double-layer CNTFS shows the best linearity, sensitivity, hysterics, and repeatability of 3.22%, 0.12684/mm, 2.16%, and 3.06%, respectively.

Keywords

• structural health monitoring
• carbon nanotube
• flexible film
• layer-by-layer self-assembly method
• piezoresistive sensing performance