Pressure and touch sensitivity is crucial for intuitive human‐machine interfaces. Here, we investigate the use of different microstructured elastomers for use as dielectric material in capacitive ...pressure sensors. We use finite element modeling to simulate how different microstructures can reduce the effective mechanical modulus. We found that pyramidal structures are optimal shapes that reduce the effective mechanical modulus of the elastomer by an order of magnitude. We also investigate the dependence of spacing of the pyramidal microstructures and how it impacts mechanical sensitivity. We further demonstrate the use of these elastomeric microstructures as the dielectric material on a variety of flexible and stretchable substrates to capture touch information in order to enable large area human‐computer interfaces for next generation input devices, as well as continuous health‐monitoring sensors.
A highly sensitive and flexible pressure sensors using microstructured dielectric to measure fingertip pulse pressure for mobile health applications. The sensor can detect pulsations at the fingertip and can be made on various flexible and stretchable substrates to capture touch information, in order to facilitate large area human–computer interfaces for next generation input devices and continuous health‐monitoring sensors.
Conducting polymer hydrogels represent a unique class of materials that synergizes the advantageous features of hydrogels and organic conductors and have been used in many applications such as ...bioelectronics and energy storage devices. They are often synthesized by polymerizing conductive polymer monomer within a nonconducting hydrogel matrix, resulting in deterioration of their electrical properties. Here, we report a scalable and versatile synthesis of multifunctional polyaniline (PAni) hydrogel with excellent electronic conductivity and electrochemical properties. With high surface area and three-dimensional porous nanostructures, the PAni hydrogels demonstrated potential as high-performance supercapacitor electrodes with high specific capacitance (∼480 F·g ⁻¹), unprecedented rate capability, and cycling stability (∼83% capacitance retention after 10,000 cycles). The PAni hydrogels can also function as the active component of glucose oxidase sensors with fast response time (∼0.3 s) and superior sensitivity (∼16.7 μA·mM ⁻¹). The scalable synthesis and excellent electrode performance of the PAni hydrogel make it an attractive candidate for bioelectronics and future-generation energy storage electrodes.
Networks of sensors placed on the skin can provide continuous measurement of human physiological signals for applications in clinical diagnostics, athletics and human-machine interfaces. Wireless and ...battery-free sensors are particularly desirable for reliable long-term monitoring, but current approaches for achieving this mode of operation rely on near-field technologies that require close proximity (at most a few centimetres) between each sensor and a wireless readout device. Here, we report near-field-enabled clothing capable of establishing wireless power and data connectivity between multiple distant points around the body to create a network of battery-free sensors interconnected by proximity to functional textile patterns. Using computer-controlled embroidery of conductive threads, we integrate clothing with near-field-responsive patterns that are completely fabric-based and free of fragile silicon components. We demonstrate the utility of the networked system for real-time, multi-node measurement of spinal posture as well as continuous sensing of temperature and gait during exercise.
Flexible/stretchable electronic devices and systems are attracting great attention because they can have important applications in many areas, such as artificial intelligent (AI) robotics, ...brain–machine interfaces, medical devices, structural and environmental monitoring, and healthcare. In addition to the electronic performance, the electronic devices and systems should be mechanically flexible or even stretchable. Traditional electronic materials including metals and semiconductors usually have poor mechanical flexibility and very limited elasticity. Three main strategies are adopted for the development of flexible/stretchable electronic materials. One is to use organic or polymeric materials. These materials are flexible, and their elasticity can be improved through chemical modification or composition formation with plasticizers or elastomers. Another strategy is to exploit nanometer‐scale materials. Many inorganic materials in nanometer sizes can have high flexibility. They can be stretchable through the composition formation with elastomers. Ionogels can be considered as the third type of materials because they can be stretchable and ionically conductive. This article provides the recent progress of soft functional materials development including intrinsically conductive polymers for flexible/stretchable electrodes, and thermoelectric conversion and polymer composites for large area, flexible stretchable electrodes, and tactile sensors.
Flexible/stretchable electronic devices and systems can have important application in many areas. They require some electronic materials to be mechanically flexible or even stretchable. The recent progress of soft functional materials development is discussed, including intrinsically conductive polymers for flexible/stretchable electrode and thermoelectric conversion and polymer composites for large‐area, flexible stretchable electrodes, and tactile sensors.
Human skin relies on cutaneous receptors that output digital signals for tactile sensing in which the intensity of stimulation is converted to a series of voltage pulses. We present a power-efficient ...skin-inspired mechanoreceptor with a flexible organic transistor circuit that transduces pressure into digital frequency signals directly. The output frequency ranges between 0 and 200 hertz, with a sublinear response to increasing force stimuli that mimics slow-adapting skin mechanoreceptors. The output of the sensors was further used to stimulate optogenetically engineered mouse somatosensory neurons of mouse cortex in vitro, achieving stimulated pulses in accordance with pressure levels. This work represents a step toward the design and use of large-area organic electronic skins with neural-integrated touch feedback for replacement limbs.
Human skin is a remarkable organ. It consists of an integrated, stretchable network of sensors that relay information about tactile and thermal stimuli to the brain, allowing us to maneuver within ...our environment safely and effectively. Interest in large‐area networks of electronic devices inspired by human skin is motivated by the promise of creating autonomous intelligent robots and biomimetic prosthetics, among other applications. The development of electronic networks comprised of flexible, stretchable, and robust devices that are compatible with large‐area implementation and integrated with multiple functionalities is a testament to the progress in developing an electronic skin (e‐skin) akin to human skin. E‐skins are already capable of providing augmented performance over their organic counterpart, both in superior spatial resolution and thermal sensitivity. They could be further improved through the incorporation of additional functionalities (e.g., chemical and biological sensing) and desired properties (e.g., biodegradability and self‐powering). Continued rapid progress in this area is promising for the development of a fully integrated e‐skin in the near future.
Human skin is a complex organ. There is much interest in developing large‐area networks of electronic devices inspired by human skin for use in autonomous intelligent robots and biomimetic prosthetics. Flexible and stretchable electronic networks that are integrated with multiple functionalities already provide augmented performance over their organic counterpart. Continued research in this area is promising for the fabrication of a fully integrated e‐skin.
Stretchable Organic Solar Cells Lipomi, Darren J.; Tee, Benjamin C.-K.; Vosgueritchian, Michael ...
Advanced materials,
04/2011, Letnik:
23, Številka:
15
Journal Article
Recenzirano
Odprti dostop
A stretchable organic solar cell was fabricated by spin‐coating the transparent electrode and active layer on a pre‐strained elastomeric membrane. Upon release of the pre‐strain, the device buckled. ...The topographic waves that arose imparted elasticity to the device under tensile strain (up to 27%). The device exhibited similar photovoltaic properties when both stretched and unstretched.
Robots are increasingly assisting humans in performing various tasks. Like special agents with elite skills, they can venture to distant locations and adverse environments, such as the deep sea and ...outer space. Micro/nanobots can also act as intrabody agents for healthcare applications. Self‐healing materials that can autonomously perform repair functions are useful to address the unpredictability of the environment and the increasing drive toward the autonomous operation. Having self‐healable robotic materials can potentially reduce costs, electronic wastes, and improve a robot endowed with such materials longevity. This review aims to serve as a roadmap driven by past advances and inspire future cross‐disciplinary research in robotic materials and electronics. By first charting the history of self‐healing materials, new avenues are provided to classify the various self‐healing materials proposed over several decades. The materials and strategies for self‐healing in robotics and stretchable electronics are also reviewed and discussed. It is believed that this article encourages further innovation in this exciting and emerging branch in robotics interfacing with material science and electronics.
Self‐healing materials are exciting avenues toward sustainable and intelligent long lifespan robots. The history and recent advances in material strategies for self‐healing in robotics and stretchable electronics toward future development of the fully autonomous self‐healing robots are reviewed.
Abstract
Human skin is a self-healing mechanosensory system that detects various mechanical contact forces efficiently through three-dimensional innervations. Here, we propose a biomimetic ...artificially innervated foam by embedding three-dimensional electrodes within a new low-modulus self-healing foam material. The foam material is synthesized from a one-step self-foaming process. By tuning the concentration of conductive metal particles in the foam at near-percolation, we demonstrate that it can operate as a piezo-impedance sensor in both piezoresistive and piezocapacitive sensing modes without the need for an encapsulation layer. The sensor is sensitive to an object’s contact force directions as well as to human proximity. Moreover, the foam material self-heals autonomously with immediate function restoration despite mechanical damage. It further recovers from mechanical bifurcations with gentle heating (70 °C). We anticipate that this material will be useful as damage robust human-machine interfaces.
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