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.