Fabrication And Sensitivity Study Of The Carbon Nanotubes Film Sensor

Recently, due to the aviation accident caused by structure deformation occurringfrequently, the health monitoring of aircraft’s structure has become one of the effective meansof prevention.The sensors used for health monitoring of structure should possess high sensitivity andbe compatible with structure, but the traditional sensors considered in terms of the structurecompatible rarely with a low sensitivity.This essay designed a carbon nanotubes film sensor wicth formed with matrix ofstructure for strain sensing and temperature sensing with high sensitivity. The dispersiontechniques such as mechanical agitation,ultrasonic processing and centrifugal processing hadbeen Combined for realizing the monodisperse of carbon nanotubes in aqueous medium. Thecarbon nanotubes film was fabricated with monodispersion solution of multi-walled carbonnanotubes through spray-vacuum filtration method. The morphology and mean pore size werecharacterized by field-emission scanning electron microscope and nitrogenadsorption-desorption. Electrical and mechanical test show that carbon nanotubes film has awell conductivity, resistance rate is0.042Ω·cm and mechanics of fracture strength is1.45MPa.The sensing mechanism of carbon nanotubes film indicate that the resistance of thecarbon nanotubes film increases with the increase of strain and decreases with the increase oftemperature. The response and sensitivity to strain and temperature of buckypaper wasinvestigated. The results indicate that buckypaper has a very high tensile strain sensitivity inthe strain range of0~55000με with gauge factor of10.21(0~39000με) and524.79(39000~55000με). And also has a high bending strain sensitivity in the strain range of0~22500με with gauge factor of188.34with a excellent reversible and repetition. Afterannealing treatment, the temperature coefficient of resistance of buckypaper were-6.57%℃-1(20~100℃) and-3.25%℃-1(100~200℃) in heating stage and-5.79%℃-1(20~100℃) and-2.88%℃-1(100~200℃) in cooling stage with a excellent reversible and repetition.