Microstructure Engineering of Stretchable Resistive Strain Sensors with Discrimination Capabilities in Transverse and Longitudinal Directions

Abstract

Featuring simple device structure, high sensitivity, and excellent reliability, stretchable resistive sensors have developed rapidly due to the high demand for flexible and wearable electronics. Nevertheless, it remains critically challenging to evaluate external stimuli using one simple device for diverse application scenarios. Here, a microstructure is engineered for a stretchable sensor by a facile replication/transferring and a prestretching/releasing process, enabling the device to have discrimination capabilities in the transverse direction (X‐axis) and longitudinal direction (Y‐axis). Consisting of silver nanowires (Ag NWs)/transition metal carbides (MXene)/poly(3,4‐ethylenedioxythiophene):poly (styrene‐sulfonate) (PEDOT:PSS) conducting layer and polydimethylsiloxane (PDMS)/Ecoflex elastomer, the microstructured sensor has a broad strain range of 120% along the X‐axis and a large gauge factor (GF) of 37.44 along the Y‐axis, and shows good stability during 1000 stretching/releasing cycles along two directions, indicating the excellent interfacial connection between the sensing layer and elastomer. As a result, taking advantages of distinct performance along two directions, the proposed stretchable sensor is demonstrated to monitor a variety of human movements and physical stimuli as a wearable and flexible device, revealing its promising potential in diverse application scenarios.

Recent advances in the construction and application of stretchable PEDOT smart electronic membranes

“…As shown in Fig. 4b-i, Shen et al 129 uniformly coated a silver nanowire (AgNW)/ transition metal carbide (MXene)/PEDOT:PSS composite conductive material (AMP) on 100% pre-stretched PDMS/Ecoflex. After releasing, the surface of the AMP forms several micronsized wrinkles (Fig.…”

Silver-Nanowire-Based Elastic Conductors: Preparation Processes and Substrate Adhesion

“…Plasma treatment can also reduce the contact angle of the hydrophobic layer to aqueous solution [ 97 ] and enhance hydrophilicity. PEDOT:PSS can be swirled on PET after it is enhanced by oxygen plasma to reduce the surface roughness of silver nanowires [ 98 ] and improve the density of the conductive network.…”

Tunneling Percolation Mechanism of Conductivity for PEDOT:PSS in Hydrophilic PDMS Composite for the Fabrication of Highly Sensitive Strain Sensors

“…GF of 148 is the maximum GF ever reported at low strains for systems based on PEDOT:PSS while others have reported GF in the range 2 to 110. [48][49][50][51][52] Conductive nanofiller composites display no obvious trend regarding the effect of fillers nor that of polymer matrix in affecting GF. [1] In general, it depends on the efficient disconnection mechanism during straining.…”