Radial alignment of carbon nanotubes for directional sensing application

Multidimensional force-sensing stretchable electronic skins made of nanomaterials with low-dimensional morphologies are of great importance in the fields of robotics, rehabilitation, and prosthetics. Herein, we report a carbon nanotube (CNT) based strain sensor with a unique alignment to detect multidirectional strains. Radially aligned CNTs sealed between polydimethylsiloxane layers exhibit a gauge factor (GF) that is comparatively better than that of a conventional CNT-based sensor. The optimum concentration of radially aligned CNTs limits the conduction path of electrons which, in turn, improves the sensitivity of the sensor. To tune the GF further, a tape-peeling method is used which not only increases the GF of the device but also improves its transparency. When attached to the human skin, the sensor can differentiate between different types of deformation. The sensor can also be employed in multichannel, interactive electronic robotics systems. It can also has potential for application as a wearable detector for human motion such as bionic ligaments in soft robotics.