3D‐Printed Coaxial Fibers for Integrated Wearable Sensor Skin

Abstract

Coaxial 3D printing technology, with its advantages of scalability and controllability, is applied in research to develop integrated wearable sensors composed of pressure sensor arrays and strain sensors. In order to improve the performance of the pressure sensor array, microstructures molded from sandpaper are introduced into the contact interface of the extruded fibers, resulting in a sensitivity (defined as the ratio of capacitance change to the change of applied pressure) of 0.562 kPa−1, a response/relaxation time of 230 ms, and a high durability. The printed strain sensor has a sensitivity (defined as the ratio of resistance change to the change of applied strain) of 11.8 and a good stability for 10 000 cycles. The high‐performance pressure sensor array and strain sensors give the integrated device the ability to detect various mechanical stimuli such as pressing, bending, twisting, and shear forces, showing potential application in the field of electronic skin.

Application-Based Production and Testing of a Core–Sheath Fiber Strain Sensor for Wearable Electronics: Feasibility Study of Using the Sensors in Measuring Tri-Axial Trunk Motion Angles

“…Flexible fiber strain sensors are commonly built on conductive components (i.e., metals [13,33], graphene [34,35], carbon nanotubes [36], carbon black [37], polymers [38,39], and ionic liquids [40,41]) and flexible polymers or substrates, as either composites or layered structures. There are a number of current methods to create layered coaxial fibers—with up to four layers—including melt spinning/extrusion [42], wet spinning [43,44], electrospinning [45,46], and newer technologies such as pressurized gyration spinning [47,48], solution blowing [49], and the use of 3D printers [50]. The advancement of manufacturing precise multilayered fibers will inevitably lead to more advanced multifunctional materials.…”

Flexible Broad‐Range Pressure Sensors Enabled by Deformation‐Induced Conductive Channels in 3D Graphene Foam@Polydimethylsiloxane Composite for Precise Vibrational Signal Detection

“…To conquer these limitations, several high efficiency and scalability methods are developed, such as, laser micro‐engineering, [ 4‐6 ] UV interface processing, [ 7 ] template‐duplication, [ 8 ] 3D printing. [ 9 ] Besides these newly developed techniques, flexible and malleable pressure sensors with non‐fragile materials also hold great promise to overcome these problems. [ 10,11 ] For instance, two‐dimensional (2D) graphene sheets with remarkable electrical and mechanical properties [ 12 ] were integrated into macroscopic structures for the fabrication of novel pressure sensors.…”

Three-dimensional printing of tactile sensors for soft robotics

“…The reason for the improved sensitivity was not provided; we postulated that the nodes in the grid-structured 3D printed electrode may concentrate the external pressure and generate a large local deformation on the dielectric layer. In addition to the regular 3D printing processes, coaxial printing 25 and fiber-encapsulation additive manufacturing (FEAM) are also applied in fabricating capacitive tactile sensors. 26…”