Ultrasensitive Linear Capacitive Pressure Sensor with Wrinkled Microstructures for Tactile Perception

Abstract

Ultrasensitive flexible pressure sensors with excellent linearity are essential for achieving tactile perception. Although microstructured dielectrics have endowed capacitive sensors with ultrahigh sensitivity, the compromise of sensitivity with increasing pressure is an issue yet to be resolved. Herein, a spontaneously wrinkled MWCNT/PDMS dielectric layer is proposed to realize the excellent sensitivity and linearity of capacitive sensors for tactile perception. The synergistic effect of a high dielectric constant and wrinkled microstructures enables the sensor to exhibit linearity up to 21 kPa with a sensitivity of 1.448 kPa−1 and a detection limit of 0.2 Pa. Owing to these merits, the sensor monitors subtle physiological signals such as various arterial pulses and respiration. This sensor is further integrated into a fully multimaterial 3D‐printed soft pneumatic finger to realize material hardness perception. Eight materials with different hardness values are successfully discriminated, and the capacitance of the sensor varies linearly (R2 > 0.975) with increasing hardness. Moreover, the sensitivity to the material hardness can be tuned by controlling the inflation pressure of the soft finger. As a proof of concept, the finger is used to discriminate pork fats with different hardness, paving the way for hardness discrimination in clinical palpation.

Hybrid Piezo-Capacitive Multimodal Sensors Based on Polyurethane–Poly(vinylidene fluoride) Nanofibers for Wearable E-Textiles

“…The hysteresis curve is plotted by varying the pressure in the range from 0 to 20 kPa and is shown in Figure S4. The PVDF 79 PU 21 nanofiber-based pressure sensor shows a hysteresis of 7%, which is low for pressure sensor based applications . The relative change in the capacitance (Δ C / C 0 ) with hand tapping on the sensor at various forces is shown in Figure f.…”

“…The PVDF 79 PU 21 nanofiber-based pressure sensor shows a hysteresis of 7%, which is low for pressure sensor based applications. 33 The relative change in the capacitance (ΔC/C 0 ) with hand tapping on the sensor at various forces is shown in Figure 1f. The results show that the PVDF 79 PU 21 nanofiber based sensor has excellent potential for detecting compressive deformation.…”

Hierarchically Structured MXene Nanosheets on Carbon Sponges with a Synergistic Effect of Electrostatic Adsorption and Capillary Action for Highly Sensitive Pressure Sensors

“…Electronic skin (e-skin) emulates the tactile functionalities of human skin, − allowing for multiple sensing capabilities such as strain, , vibration, pressure, and temperature. As a result, this technology holds vast potential in applications such as smart robotics, prosthetics, human–machine interfaces, − and wearable medical systems. , The ideal electronic skin should possess multifunctional sensing capabilities, which means that it should be able to detect different types of stimuli simultaneously. In particular, an e-skin that can simultaneously sense pressure and temperature is important for self-protection, touch recognition, , and object manipulation.…”

Flexible Capacitive Pressure Sensor with High Sensitivity and Wide Range Based on a Cheetah Leg Structure via 3D Printing

“…To prepare high-performance flexible pressure sensors, numerous researchers have dedicated their efforts to investigating materials that can be used in flexible sensors. The primary flexible materials that have been studied include silicone rubber, , poly­(dimethylsiloxane) (PDMS), , and hydrogels. , The aforementioned materials are highly flexible, enabling the preparation of nanometer-sized structures. With the use of these flexible materials, researchers can achieve more innovative structural patterns.…”