Droplets Patterning of Structurally Integrated 3D Conductive Networks-Based Flexible Strain Sensors for Healthcare Monitoring

Abstract

Flexible strain sensors with significant extensibility, stability, and durability are essential for public healthcare due to their ability to monitor vital health signals noninvasively. However, thus far, the conductive networks have been plagued by the inconsistent interface states of the conductive components, which hampered the ultimate sensitivity performance. Here, we demonstrate structurally integrated 3D conductive networks-based flexible strain sensors of hybrid Ag nanorods/nanoparticles(AgNRs/NPs) by combining a droplet-based aerosol jet printing(AJP) process and a feasible transfer process. Structurally integrated 3D conductive networks have been intentionally developed by tweaking droplets deposition behaviors at multi-scale for efficient hybridization and ordered assembly of AgNRs/NPs. The hybrid AgNRs/NPs enhance interfacial conduction and mechanical properties during stretching. In a strain range of 25%, the developed sensor demonstrates an ideal gauge factor of 23.18. When real-time monitoring of finger bending, arm bending, squatting, and vocalization, the fabricated sensors revealed effective responses to human movements. Our findings demonstrate the efficient droplet-based AJP process is particularly capable of developing advanced flexible devices for optoelectronics and wearable electronics applications.

Aerosol‐Jet Printed Sensors for Environmental, Safety, and Health Monitoring: A Review

“…In another account, an orthogonally assembled hybrid silver nanorod/nanoparticle conductive network is encased in poly(vinyl alcohol) to detect responses to human movement (e.g., joint bending, vocalization) with a reported GF of 23. [ 145 ] In addition to these developments in AJP‐based RSGs, researchers have explored the piezoelectric effect toward strain sensor development. Piezoelectricity, with its ability to convert mechanical energy into electrical signals, is particularly promising for self‐powered wearable sensor applications.…”

Temperature-Switching Flexible Strain Sensors Based on Vanadium Dioxide for Intelligent Packaging Applications

“…Common flexible substrates include polyimide (PI), poly(dimethylsiloxane) (PDMS), thermoplastic polyurethane (TPU), poly(ethylene terephthalate) (PET), and other polymers. , In addition, fabrics, paper, and sponges have also been proposed by researchers for the preparation of flexible sensors. Conductive materials mainly include carbon nanotubes, metal nanowires, metal nanoparticles, carbon black, MXene, graphene, liquid metals, and nanometal oxides . These materials are configured on flexible substrates to form a conductive network, where external strain leads to changes in conductive path length and resistance, enabling the conversion of strain into electrical signals .…”