Wood-based aligned carbon microtubule array flexible strain sensor with high sensitivity

The sensing performance of a flexible strain sensor is determined by its conductive sensing elements, which are typically made of conductive materials such as metals, conductive polymers, or carbon-based materials. Carbon material is an essential material for preparing conductive sensing elements of flexible strain sensors. The microstructures of carbon materials and the geometrical configurations of the assembled carbon-based materials show great advantages in regulating the stretchability of the carbon-based flexible strain sensor. The wood-based aligned carbon microtubule array film has great application potential in the carbon-based flexible strain sensor, which may not only achieve better balance between sensitivity and stretchability, but also achieve the balance between performance and scalability. The abundant intertubular cavities in WACTA (wood-based aligned carbon microtubule array) film facilitate the penetration of the SEBS (poly(styrene-ethylene-butylene-styrene)) encapsulated polymers, leading to improved quality of the WACTA film encapsulated by SEBS polymer. The relative resistance of the WACTA flexible strain sensor responds quasi-linear to the applied strain (0–40%). The GF (gauge factor) of the WACTA flexible strain sensor is around 30. The WACTA flexible strain sensor is capable of full-cycle complete detection of strain with high sensitivity. They also demonstrated superb electromechanical integrity in terms of stability and repeatability. The sensing performance of the WACTA flexible strain sensor showed nearly no frequency dependence. The sensor can recognize forces as low as 2.5 mN. there is a good linear relationship between the loading tiny force and the relative resistance. The sensor exhibits excellent sensitivity to tiny signals such as sound, arterial pulse, and tiny weights.