High-Performance Multidirectional Flexible Strain Sensor for Human Motion and Health Monitoring.

Multidirectional strain sensors are pivotal for wearable electronic devices and human-computer interaction. In this investigation, we translocate carbon/graphene (CB/Gr) conductive nanocomposites onto an Ecoflex flexible substrate via a facile technique encompassing reverse molding and spraying, culminating in the fabrication of a 45° strain rosette-shaped multidirectional flexible strain sensor. The sensor distinguishes itself with extraordinary performance characteristics, including high sensitivity (boasting a gauge factor of 35), an extensive strain range from 0 to 100%, exceptional linearity, a rapid response time of merely 200 ms, remarkable stability, and outstanding durability, effortlessly withstanding over 5000 stretch-release cycles. The sensor exhibits its exceptional capability to discern intricate movements, particularly in detecting human hand and neck motions. The sensor's remarkable comprehensive performance and strain direction recognition ability underscore its significant potential for diverse applications, notably in human-computer interaction, human motion monitoring, and health monitoring.

A broad range and piezoresistive flexible pressure sensor based on carbon nanotube network dip-coated porous elastomer sponge.

Flexible pressure sensors have provided an attractive option for potential applications in wearable fields like human motion monitoring or human-machine interfaces. For the development of flexible pressure sensors, achieving high performance or multifunctions are popular research tendencies in recent years, such as improving their sensitivity, working range, or stability. Sponge materials with porous structures have been demonstrated that they are one of the potential substrates for developing novel and excellent flexible pressure sensors. However, for sponge-based pressure sensors, it is still a great challenge to realize a wide range of pressures from Pa level to hundreds kPa level. And how to achieve mechanical robustness remains unsolved. Here, we develop a flexible pressure sensor based on multicarbon nanotubes (MWCNTs) network-coated porous elastomer sponge with a broad range and robust features for use in wearable applications. Specifically, polyurethane (PU) sponge is used as the substrate matrix while dip-coated PU/MWCNTs composites as a conductive layer, achieving a highly bonding effect between the substrate and the conductive material, hence a great mechanical robust advantage is obtained and the working range also is improved. The pressure sensor show range of up to 350 kPa, while the minimum detection threshold is as low as 150 Pa. And before and after rolling by a bicycle or electric motorcycle, the sensor has the almost same responses, exhibiting great robustness.