Hydrophobic and Stable MXene–Polymer Pressure Sensors for Wearable Electronics

Abstract

Ti3C2T x MXene has exhibited great potential for use in wearable devices, especially as pressure sensors, due to its lamellar structure, which changes its resistance as a function of interlayer distance. Despite the good performance of the reported pure MXene pressure sensors, their practical applications are limited by moderate flexibility, excessively high MXene conductivity, and environmental effects. To address the above challenges, we incorporated multilayer MXene particles into hydrophobic poly­(vinylidene fluoride) trifluoroethylene (P­(VDF-TrFE)) and prepared freestanding, flexible, and stable films via spin-coating. These films were assembled into highly sensitive piezoresistive pressure sensors, which show a fast response time of 16 ms in addition to excellent long-term stability with no obvious responsivity attenuation when the sensor is exposed to air, even after 20 weeks. Moreover, the fabricated sensors could monitor human physiological signals such as knee bending and cheek bulging and could be used for speech recognition. The mapping spatial pressure distribution function was also demonstrated by the designed 10 × 10 integrated pressure sensor array platform.

Recent Progress in Flexible Pressure Sensors Based Electronic Skin

“…[106] Copyright 2020, Springer Nature. "Structure" polymers (e.g., PPy, [11] poly(3,4-ethylene dioxythiophene): poly(styrene sulfonate) [PEDOT:PSS], [47] and hydrogel [14] ), and other materials (e.g., MOF, [35] MXene [48,49] ). The performance of these active materials have exhibited excellent mechanical properties, excellent electrical conductivity, and long-term stability.…”

“…Flexible piezoresistive sensors skin‐like can be categorized into two parts—supporting materials and active materials. The most used active materials are metal‐based materials (e.g., liquid metals, [ 41 ] metal particles, [ 42 ] and NWs [ 43 ] ), carbon‐based materials (e.g., carbon black [CB], [ 44 ] CNT, [ 45 ] and graphene [ 46 ] ), conductive polymers (e.g., PPy, [ 11 ] poly(3,4‐ethylene dioxythiophene):poly(styrene sulfonate) [PEDOT:PSS], [ 47 ] and hydrogel [ 14 ] ), and other materials (e.g., MOF, [ 35 ] MXene [ 48,49 ] ). The performance of these active materials have exhibited excellent mechanical properties, excellent electrical conductivity, and long‐term stability.…”

MXene Enabling the Long-Term Superior Thermo-Oxidative Resistance for Elastomers

“…Based on these limitations, it is a challenge for us to further explore another strategy to prolong the antiaging effect. MXenes, as a kind of two-dimensional early transition metal carbides and carbonitrides, have been widely researched [19][20][21][22][23]. When the size of materials decreases to the nanoscale, such materials often exhibit surprising properties.…”

MXtrodes: MXene-infused bioelectronic interfaces for multiscale electrophysiology and stimulation

“…It is made of Earth-abundant elements and no cytotoxicity has been observed in previous studies (37). In the past few years, Ti3C2 has attracted great attention for a number of biomedical applications (38), including cancer theranostics (39), hemodialysis (40), and wearable mechanical sensors (41,42). Our group has pioneered the use of Ti3C2 for implantable neural microelectrodes (43,44) and skin-conformable, thinfilm wearable sensors (45).…”