Broadband dynamic responses of flexible carbon black/poly (vinylidene fluoride) nanocomposites : a sensitivity study

Abstract

Nanocomposites fabricated based on a compound of carbon nanofiller and polymer matrix exhibit extraordinary piezoresistive performance, and the capacity of nanocomposite sensors in measuring structural dynamic strains has been widely demonstrated. However, the sensitivity of existing nanocomposite strain sensors is limited, particularly in aspects of sensing precision and response frequency. This study focuses on sensitivity investigations of flexible nanocomposite sensors fabricated using a compound of carbon black (CB) fillers and polyvinylidene fluoride (PVDF) matrix, which has shown promising potential in perceiving extremely weak strain signals within a considerably broad range of response frequencies. As a highly important indication of sensitivity, sensing precision was characterized in a quantitative manner. Broadband spectrum analysis was conducted as an effective way to examine sensor performance in perceiving minimal disturbances in dynamic strains. Disturbances were generated in two experiments, by introducing local material and geometric variations into the inspected structures, in terms of mass attachment and structural damage. The effectiveness of the nanocomposites in structural damage detection was demonstrated. Moreover, the experimental results indicate the promising potential of nanocomposite-based strain sensors for applications such as advanced bioelectronics, ultrasonic inspection, and in-situ structural health monitoring.