Flexible strain sensors with high sensitivity and large monitoring range prepared by biaxially stretching conductive polymer composites with a bilayer structure

In order to prepare a flexible strain sensor with a large monitoring range, high sensitivity and excellent stability, a polyolefin elastomer (POE)/carbon nanotubes (CNTs) conductive polymer composite with a bilayer structure was prepared by biaxially stretching in this work. The results showed that the bilayer structured nanocomposites had better processability and better stability than monolayer CNT/POE nanocomposites during biaxial stretching. The biaxial stretching process could promote the dispersion and planar orientation of CNTs within the polymer, improving the crystallinity of nanocomposites and the sensing performance of strain sensors. The optimal stretching ratios (SRs) of bilayer structured nanocomposites were studied. The 8 wt% CNT/POE-POE strain sensor with an SR of 2.5 exhibited a high sensitivity (gauge factor/GF = 72604.7 at 900% strain), wide strain range (0%-900%), and stable cycling performance (1000 cycles at 30% strain), showing a broad application prospect in wearable electronic devices. This study provides a valuable method for efficiently manufacturing high performance and low-cost flexible strain sensors. High-performance flexible strain sensors were prepared by bixially stretching a bilayer structured CNT/POE composites.image