Highly stretchable and sensitive strain sensors based on carbon nanotube-elastomer nanocomposites: The effect of environmental factors on strain sensing performance

There is an increasing demand for stretchable and wearable strain sensors because of their potential in human motion detection, healthcare monitoring, and soft robotics. Besides their high stretchability and high sensitivity, the durability of wearable strain sensors under variations in atmospheric conditions is another important consideration for their practical use. To date, however, little attention has been given to the impact of environmental factors on the sensing performance of stretchable strain sensors. Herein, we present highly stretchable and sensitive strain sensors based on carbon nanotube-polydimethylsiloxane nanocomposite films and systematically investigate the effect of environmental parameters (i.e., changes in temperature and relative humidity) on their strain sensing characteristics. The strain sensors possess a maximum gauge factor of around 10, stretchability of up to 60%, and response time of 204 ms with good reliability and low hysteresis. Our detailed study on the long-term exposure of strain sensors to controlled temperature and relative humidity levels reveals their significant influence on the strain sensing behavior, particularly temperature fluctuations. As application demonstrations, the stretchable strain sensors are utilized to track the deformation state of an air-inflated balloon and human body movements for healthcare monitoring.