Super-hydrophobic, durable and cost-effective carbon black/rubber composites for high performance strain sensors

Conductive polymer composite (CPC) because of its light weight, and good flexibility has become a candidate for wearable strain sensors; however high cost, relatively low responsivity and poor corrosion resistance have severely restricted its practical applications. In this study, we use the commercially available rubber band (RB) and low cost carbon black nanoparticles (CBNPs) as the polymer matrix and conductive nanofillers to fabricate super-hydrophobic CPC for wearable strain sensors. CBNPs are evenly distributed onto the swollen RB surface with the help of ultrasonication. Then, the obtained RB/CBNPs composite with a rough surface is modified with polydimethylsiloxane (PDMS), which can not only endow the composite with super-hydrophobicity but also largely improve the interface adhesion between the RB and CBNPs. The obtained super-hydrophobic RB/CBNPs/PDMS composite shows excellent water repellence and anti-corrosive performance and the composite almost maintains its super-hydrophobicity even after cyclic surface wear test, exhibiting extraordinary durability. Also, the RB/CBNPs/PDMS strain sensor exhibits excellent tensile property with a 980% elongation at break, high sensitivity with a gauge factor of 242.6 (epsilon = 38.8%-71.4%), outstanding repeatability during the cyclic stretching-releasing tests and can be used to detect full-range body movement.