Wearable, Ultrawide-Range, and Bending-Insensitive Pressure Sensor Based on Carbon Nanotube Network-Coated Porous Elastomer Sponges for Human Interface and Healthcare Devices

Abstract

Flexible and wearable pressure sensors have attracted a tremendous amount of attention due to their wider applications in human interfaces and healthcare monitoring. However, achieving accurate pressure detection and stability against external stimuli (in particular, bending deformation) over a wide range of pressures from tactile to body weight levels is a great challenge. Here, we introduce an ultrawide-range, bending-insensitive, and flexible pressure sensor based on a carbon nanotube (CNT) network-coated thin porous elastomer sponge for use in human interface devices. The integration of the CNT networks into three-dimensional microporous elastomers provides high deformability and a large change in contact between the conductive CNT networks due to the presence of micropores, thereby improving the sensitivity compared with that obtained using CNT-embedded solid elastomers. As electrical pathways are continuously generated up to high compressive strain (∼80%), the pressure sensor shows an ultrawide pressure sensing range (10 Pa to 1.2 MPa) while maintaining favorable sensitivity (0.01–0.02 kPa–1) and linearity (R 2 ∼ 0.98). Also, the pressure sensor exhibits excellent electromechanical stability and insensitivity to bending-induced deformations. Finally, we demonstrate that the pressure sensor can be applied in a flexible piano pad as an entertainment human interface device and a flexible foot insole as a wearable healthcare and gait monitoring device.

Micro‐Nano Processing of Active Layers in Flexible Tactile Sensors via Template Methods: A Review

“…The first strategy is to coat polymers on sacrificial or etched skeletons (such as nickel foam, [178][179][180][181] cube sugar [86,[182][183][184] ), and then immerse them in the etching solution after curing to sacrifice the skeleton, thereby obtaining the foam structure. As shown in Figure 11a, Zhao et al [32] used the APCVD to grow a graphene network on a Ni foam template and then immersed it in the PDMS precursor mixture.…”

Applications of Carbon Nanotubes in the Internet of Things Era

“…Besides, the composite materials have been developed for the non-volatile memory [12] for data storage [13]. The input devices start emerging with the keypad [14], joystick [15], and touchpad [16]. Meanwhile, the output devices such as display were demonstrated based on CNT driving electrodes [17] and lightening [18][19][20].…”

Ultra‐Wide Range Pressure Sensor Based on a Microstructured Conductive Nanocomposite for Wearable Workout Monitoring

“…Soft materials such as polydimethylsiloxane and Ecoflex are typically utilized for the fabrication of flexible pressure sensors thanks to their low elastic modulus, high stretchability, and humanfriendliness. [10,13,[16][17][18] However, these elastomers suffer from structural saturation at low pressures, making their use challenging in applications that involve high pressures. [19] Additionally, it is highly desirable to fabricate flexible pressure sensors in planar thin-film type, which can lead to high adaptability to be attached to surfaces with complex shapes as an add-on component.…”