Aligned silver Nanowires/Polymer composite films for ultrasensitive and highly stretchable strain sensors

Strain sensor films are widely applied in electronic skins, soft robotics and human health monitoring etc. However, fabrication of ultrasensitive and highly stretchable strain sensor films remains a great challenge because of the trade-off between sensitivity and stretchability. Here, we report an aligned silver nanowires (Ag NWs)/polymer composite film prepared by a float assembly method. After perpendicularly stacking two layers of Ag NWs/polymer composite films into one sensor film, it exhibits an ultrahigh sensitivity with gauge factor (GF) up to 2.98 × 106 and a very large working range of 200% due to different resistance response mechanism of the cross film structure. The low limit of detection is as low as 0.001%. Accordingly, the strain sensor films can detect both large deformation and subtle vibration for human motion and monitoring, even early warning of earthquakes. This work provides a new idea to fabricate stain sensor films with both ultrahigh sensitivity and large stretchability.