Preparation and Application of Flexible Pressure/ Strain Sensors Based on Loofahs

Flexible multidirectional sensors are essential for complex motion detection in flexible sensing applications. Here, a flexible pressure sensor and an anisotropic strain sensor with multifunctional high sensitivity and wide measurement range are presented, which consists of a natural porous loofah as a flexible skeleton and a carbon nanoparticle/multiwalled carbon nanotube (CN/MWCNT) multiscale composite as a conductive coating. The flexible anisotropic pressure/strain sensor made from loofah as a substrate has high flexibility, fast response time (< 100 ms), and high durability (>10000 cycles). In particular, the sensor shows different gauge factors (GFs) in the circumferential and axial directions when strain is applied. This anisotropic sensing property is well maintained in the sensor because of the neatly aligned cellulose fibers of the loofah. In addition, the practical application of the sensor in detecting complex human motions is demonstrated, showing its potential for applications in areas, such as multidimensional wearable electronic devices.