Highly stretchable conductive elastomeric polyurethane nanofiber composite for human motion detection

•A conductive nanofiber composite is successfully fabricated by in situ reduction Ag NPs.•The conductive TPU nanofiber composite demonstrates good stability in harsh conditions.•The nanofiber composite sensor possesses a high sensitivity andbroad working range.•The sensor was able to detect full range detection of human body motions. Flexible strain sensors have received wide attention due to their potential applications in wearable devices. However, the development of strain sensors with higher stretchability, and larger workable strain range still remains a challenge. Here, a conductive nanofiber composite with a hierarchical silver nanoparticles (Ag NPs) shell and thermoplastic polyurethane (TPU) nanofiber core microstructure are constructed via depositing Ag NPs on TPU nanofiber mats surface with the aid of tannic acid (TA) and hydrolysable 3-aminopropyltriethoxysilane (APTES) hybrid coating (TA-APTES coating). The prepared strain sensor demonstrates high stretchability with maximum strain of 565% and high sensitivity with a gauge factor (GF) of about 6886. In addition, the TPU@(TA-APTES)@Ag NPs composite strain sensor can be applied to detect human motions.