Carbon nanotubes based multi-directional strain sensor
A. Santos, L. Amorim, J. P. Nunes, Alexandre Ferreira da Silva, Júlio C. Viana
Abstract
In this work a new carbon nanotubes (CNT) based multi-directional strain sensor capable of quantifying and indicate strain direction is foreseen. This work investigates the electromechanical behavior of an aligned CNT sensing patch strained at 45° in order to validate its multi-directional sensing capability. Vertically aligned CNT forests are produced by chemical vapor deposition (CVD) and then mechanically knocked down onto polyimide (PI) films. Two configurations, diamond (D sample) and square (Sq sample), are considered. The relative electrical resistance ( ΔR/R 0 ) and the electrical anisotropy ( R B /R A ) upon strain increments are analyzed and compared to previous work results (0° and 90° strain direction). Both 45° samples, D and Sq, are sensitive to strain. A correlation between electrical anisotropy behavior and strain direction (0°, 45° and 90°) is established. The results show that with only an aligned CNT small patch it is possible to quantify and indicate strain in three directions.