Electronic skins equip robots and biomedical devices with intuitive skin‐like sensitivity. Performance‐driven design of electronic skins is a critical need for electronic or biomedical applications. ...Prior research primarily focuses on investigating effects of microstructures on sensor performance at low pressure ranges. However, having predictive and tunable electro–mechanical responses across an extensive pressure range (>100 kPa) is paramount. Here, the authors propose a system that virtually customizes micropyramids for e‐skin sensors. The associations between geometry parameters, material properties, and single‐pyramid performance are systematically explored via numerical simulations, empirical characterizations, and analytical solutions. These experimentally validated models allow for the determination of the sensor parameters for the desired performance. An augmented reality interface system for surgery skills training by optimizing sensitivities that match varying tissue stiffnesses is further demonstrated. The platform enables greater effectiveness in rapidly iterating and designing micropyramidal e‐skin for applications in augmented reality interfaces, robotics, and telehealthcare.
An augmented reality surgical interface system can aid in surgical training of hand stability. Piezo‐capacitive sensors made using pyramidal microstructures transduce tactile feedbacks and the data are used for conducting virtual excisions. Sensor performance is tuned with the new predictive mechanical models developed through single‐pyramid level microstructure indentation measurements.
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BFBNIB, FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SAZU, SBCE, SBMB, UL, UM, UPUK
Inhomogeneous swelling of polymer films in liquid environments may find applications in soft actuators and sensors. Among them, fluoroelastomer based films bend up spontaneously once they are placed ...on an acetone-soaked filter paper. The stretchability and dielectric properties of a fluoroelastomer is attractive in the fields of soft actuators and sensors, making in-depth studies on and understanding of fluoroelastomer bending behaviors important. Here, we report an abnormal size-dependent bending phenomenon of rectangular fluoroelastomer films, which transform the bending direction from the long-side bending to the short-side bending as their length or width increases or the thickness decreases. By using finite element analysis and an analytical expression obtained using a bilayer model, we reveal the key role of gravity in determining the size-dependent bending behavior. In the bilayer model, an energy quantity is obtained to characterize the role of each material and geometrical parameters in determining the size-dependent bending behavior. We further construct phase diagrams to correlate the bending modes and the film sizes based on the finite element results, which are in good agreement with experimental results. These findings can be useful for the design of future swelling-based polymer actuators and sensors.
The phase diagram reveals how the bending of a rectangular bilayer is influenced by its size, specifically in terms of length, width, and thickness.
This article presents a versatile soft robotic gripper system whereby its fingers can be reconfigured into different poses such as scoop, pinch, and claw. This allows the gripper to efficiently and ...safely handle food samples of different shapes, sizes and stiffness such as uncooked tofu and broccoli floret. The 3D-printed fingers were tested to last up to 25 000 cycles without significant changes in the curvature profile and force output profile. A benchmark experiment was conducted to evaluate the performance of the gripper and state-of-the-art gripping solutions. Capability of versatile soft gripper was optimized by integrating vision and tactile sensing facilities. An object recognition system was developed to identify food samples such as potato, broccoli, and sausage. Position and orientation of food samples were identified and pick-and-place pathway was optimized to achieve the best gripping performance. Flexible tactile sensors were integrated into soft fingers and closed-loop force feedback control system was developed. This allowed the gripper to automatically explore and select the most stable grip pose for different food samples. Integration of vision and force feedback system ensure that objects detected by the system would be firmly gripped. The reconfigurable soft robotic gripper system has been demonstrated to perform high-speed pick-and-place tasks (∼3 s per item) with object recognition system, making it a potential solution to food and grocery supply chain needs.
Power sources with good mechanical compliance are essential for various flexible and stretchable electronics. However, most of the current energy storage devices comprise of hazardous materials that ...may cause environmental pollution when improperly disposed. We show the first example of a stretchable, yet fully degradable battery made from nontoxic and environmentally friendly materials such as fruit‐based gel electrolytes and cellulose paper electrodes. The battery exhibits an areal capacity of 2.9 μAh cm−2 at 40 μA cm−2, corresponding to a maximum energy density around 4.0 μW h cm−2 at 56 μW cm−2 power density. The biomaterials constituted battery shows good mechanical tolerance to twisting, bending, and stretching while powering various electronic devices when combined with kirigami. Importantly, the entire battery disintegrates readily in phosphate buffered saline/cellulase solution. We integrate the “green” battery with various sensors in wearable healthcare devices for pulsation sensing and low‐noise surface electromyography applications.
Stretchable and fully degradable batteries inspired by lemon battery and kirigami handicraft as environmentally friendly power source for wearable electronics.
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FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SAZU, SBCE, SBMB, UL, UM, UPUK
The development of modern robotics has triggered increasing interest in developing artificial tactile sensory systems. However, the tactile mechanism in the design process has been highly limited to ...experimental tests that are expensive and time-consuming. This work is concerned with the development of using virtual tests for tactile sensory response prediction and design, which includes numerical simulation settings, database creation, response regression and interpolation, and sensor sensitivity designs. Experimental verifications and numerical demonstrations are performed based on the NUS NeuTouch sensors. The potential of using virtual tests to design new tactile sensors to improve response linearity is illustrated.
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•Tactile response prediction and design using virtual tests is proposed with demonstration on NUS NeuTouch sensors.•The framework consists of numerical simulations, database creation, response regression and interpolation.•The potential of using virtual tests to design new tactile sensors for improving response linearity is illustrated.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
Ambipolar organic field‐effect transistors (OFETs) are promising candidates for compact organic complementary circuits. High and balanced ambipolar mobilities that facilitate high operation speed and ...simplifying layout designs, as well as symmetric electrodes that minimize fabrication complexity are critical integrities for state‐of‐art ambipolar OFETs. Organic single crystals with intrinsic ambipolar characteristics are ideal active layer materials because of the high molecular ordering and low density of defects, whereas the generally low electron mobility hindered their further implantation. In this work, the highly crystallized 6,13‐bis(triisopropylsilylethynyl) pentacene single crystals are employed and successfully unveiled the intrinsic high electron mobility by a facile alcohol treatment approach. The resulting ambipolar OFETs showed averaged hole and electron mobilities both higher than 1 cm2 V−1 s−1 by a single type of metal electrode. The presented ambipolar OFETs not only improved the static and dynamic performance of ambipolar OFET‐based complementary inverters and ring oscillators by showing a high voltage gain of 186 and a short stage delay time of 0.7 ms, but they also allowed one logic gate to show two logic functions and potentially benefit the design and functionalities of future OFET‐based complementary circuits as well.
The highly crystallized TIPS‐pentacene single crystals are employed and the intrinsic high electron mobility is successfully unveiled by a facile alcohol treatment approach. The resulting ambipolar organic field‐effect transistors (OFETs) show averaged hole and electron mobilities both higher than 1 cm2 V−1 s−1 by a single type of metal electrode.
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FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SAZU, SBCE, SBMB, UL, UM, UPUK
An intrinsic self-healing material composed of poly-vinylidene-fluoride (PVDF) based fluoroelastomer with the addition of a small amount of non-ionic fluorinated surfactant was studied as a candidate ...material for electrical insulating purposes. Structural and thermal properties were analyzed with Fourier transform infrared spectroscopy and simultaneous thermal analysis. Broadband dielectric spectroscopy, volume and surface resistivity, and dielectric strength measurements provided a comprehensive overview of the dielectric properties. The material has a relatively high thermal stability (200 °C), a low dielectric strength of 13 kV/mm, and volume and surface resistivities of 1.07E+09 \Omega\cdot cm and 1.94E+09 \Omega, respectively. Due to various polarization effects, relative permittivity values are generally higher and increase with the loss factor at temperatures above 30 °c and at low frequencies (50 Hz). It was also found from high voltage testing that decomposition of the self-healing material was initiated by carbonization of the melt phase generated in the ignition area. Although a self-healing layer arises shortly after the destructive breakdown, the channel recovery activity is not consistent because of the material's low viscosity. These initial results obtained on a novel dipole-dipole based self-healing material composite can serve as a reference point for further development - to reduce the overall polarity of the system and improve the dielectric properties, while maintaining its selfhealing ability.
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