Advances in Materials for Soft Stretchable Conductors and Their Behavior under Mechanical Deformation

Abstract

<jats:p>Soft stretchable sensors rely on polymers that not only withstand large deformations while retaining functionality but also allow for ease of application to couple with the body to capture subtle physiological signals. They have been applied towards motion detection and healthcare monitoring and can be integrated into multifunctional sensing platforms for enhanced human machine interface. Most advances in sensor development, however, have been aimed towards active materials where nearly all approaches rely on a silicone-based substrate for mechanical stability and stretchability. While silicone use has been advantageous in academic settings, conventional silicones cannot offer self-healing capability and can suffer from manufacturing limitations. This review aims to cover recent advances made in polymer materials for soft stretchable conductors. New developments in substrate materials that are compliant and stretchable but also contain self-healing properties and self-adhesive capabilities are desirable for the mechanical improvement of stretchable electronics. We focus on materials for stretchable conductors and explore how mechanical deformation impacts their performance, summarizing active and substrate materials, sensor performance criteria, and applications.</jats:p>

3D‐Printed Stacked Ionic Assemblies for Iontronic Touch Sensors

“…Different from resistive‐type sensors that only exhibit a single layer of active material in the form of percolated elastomer‐conductive filler composite, capacitive‐type sensors generally require a dielectric layer sandwiched between two soft conducting electrodes. [ 1a,5 ] Piezoelectric‐type sensors represent an alternate approach in which a change in electrical polarization inside the material in response to external mechanical load results in a change in surface charge of the material. [ 6 ] Triboelectric‐type sensors also represent an interesting alternative where mechanical energy is converted into electricity based on the coupling effect of contact electrification and electrostatic induction.…”

Liquid Metal based Stretchable Room Temperature Soldering Sticker Patch for Stretchable Electronics Integration

“…Researchers in the field of stretchable electronics have been endeavoring to develop a stretchable conductor to bring advances in wearable electronics, soft robotics, and human-machine interfaces. [1][2][3][4][5] The exertion brought about significant development in electrical conductors that are highly stretchable, electromechanically decoupled, and durable under harsh conditions. Nevertheless, the stretchable conductors must be integrated with highly advanced commercial surface mount chips to fabricate a practical stretchable electronic device.…”

Self‐Healable Spider Dragline Silk Materials

“…[6,7] To enable the so-called "soft" electronics technology, mechanically malleable and stretchable materials are combined with electrical components or conductive fillers. [8][9][10] Several petroleumbased chemically-synthesized elastomers (polyvinyl alcohol, polyethylene terephthalate, polydimethylsiloxane, polyimide, and polyurethane) have been intensively explored as elastic matrices in the production of soft electronics with remarkable success. [11] In addition, a newly engineered attribute of elastomer materials, self-healing, has been granted as a unique and favorable function for soft electronics and mechanics.…”