Significant strain-rate dependence of sensing behavior in TiO2@carbon fibre/PDMS composites for flexible strain sensors

Carbon fibre (CF) embedded into elastomeric media has been attracting incredible interest as flexible strain sensors in the application of skin electronics owing to their high sensitivity in a very small strain gauge. To further improve the sensitivity of CF/PDMS composite strain sensor, the relatively low temperature prepared TiO2 nanowire via hydrothermal route was employed herein to functionalize CF. The results showed a significant increase in the sensitivity of the TiO2@CF/PDMS composite strain sensors which was reflected by the calculated gauge factor. As the prepared TiO2 nanowire vertically embraced the surroundings of the CF, the introduced TiO2 nanowire contributed to a highly porous structure which played a predominant role in improving the sensitivity of strain sensors. Moreover, the significant strain rate dependent behavior of TiO2@CF/PDMS strain sensor was revealed when performing monotonic tests at varied strain rate. Therefore, introducing TiO2 nanowire on CF offers a new technique for fabricating flexible strain sensors with improved sensitivity for the application of flexible electronics.