56 research outputs found
Durable and Water-Floatable Ionic Polymer Actuator with Hydrophobic and Asymmetrically Laser-Scribed Reduced Graphene Oxide Paper Electrodes
No full textIonic polymer actuators driven by electrical stimuli have been widely investigated for use in practical applications such as bioinspired robots, sensors, and biomedical devices. However, conventional ionic polymer metal composite actuators have a serious drawback of poor durability under long-term actuation in open air, mainly because of the leakage of the inner electrolyte and hydrated cations through cracks in the metallic electrodes. Here, we developed a highly durable and water-floatable ionic polymer artificial muscle by employing hydrophobic and asymmetrically laser-scribed reduced graphene oxide paper electrodes (HLrGOP). The highly conductive, flexible, and cost-effective HLrGOP electrodes have asymmetrically smooth hydrophobic outer and rough inner surfaces, resulting in liquid-impermeable and water-floatable functionalities and strong bonding between an ionic polymer and the electrodes. More interestingly, the HLrGOP electrode, which has a unique functionality to prevent the leakage of the vaporized or liquid electrolyte and mobile ions during electrical stimuli, greatly contributes to an exceptionally durable ionic polymer graphene composite actuator that is a prerequisite for practical applications in active biomedical devices, biomimetic robots, touch-feedback haptic systems, and flexible soft electronics
Skin‐like Omnidirectional Stretchable Platform with Negative Poisson's Ratio for Wearable Strain–Pressure Simultaneous Sensor
No full textConventional elastomeric polymers used as substrates for wearable platforms have large positive Poisson's ratios (approximate to 0.5) that cause a deformation mismatch with human skin that is multidirectionally elongated under bending of joints. This causes practical problems in elastomer-based wearable devices, such as delamination and detachment, leading to poorly reliable functionality. To overcome this issue, auxetic-structured mechanical reinforcement with glass fibers is applied to the elastomeric film, resulting in a negative Poisson's ratio (NPR), which is a skin-like stretchable substrate (SLSS). Several parameters for determining the materials and geometrical dimensions of the auxetic-structured reinforcing fillers are considered to maximize the NPR. Based on numerical simulation and digital image correlation analysis, the deformation tendencies and strain distribution of the SLSS are investigated and compared with those of the pristine elastomeric substrate. Owing to the strain-localization characteristics, an independent strain-pressure sensing system is fabricated using SLSS with a Ag-based elastomeric ink and a carbon nanotube-based force-sensitive resistor. Finally, it is demonstrated that the SLSS-based sensor platform can be applied as a wearable device to monitor the physical burden on the wrist in real time.
Beyond a Nature-inspired Lotus Surface: Simple Fabrication Approach Part I. Superhydrophobic and Transparent Biomimetic Glass Part II. Superamphiphobic Web of Nanofibers
No full textNon
Electronic structure of conducting Al-doped ZnO films as a function of Al doping concentration
No full textTransparent conducting Al-doped ZnO films were deposited by atomic layer deposition with various of Al doping concentrations. In order to explain the change in resistivity of Al-doped ZnO films depending on Al doping concentration, we investigated the correlations between the conducting property and electronic structure in terms of atomic configuration, the evolution of the conduction band and band gap, and band alignments (conduction band offset between minimum of conduction band and Fermi level, Delta E-CB). ZnO film Al-doped at similar to 3 at% and deposited at 250 degrees C showed the lowest resistivity, which resulted in changes in the conduction band of insulating Al2O3 film, and increases in the band gap and conduction band offset (Delta E-CB). (C) 2014 Elsevier Ltd and Techna Group S.r.l. All rights reserved
Design and fabrication of a superhydrophobic glass surface with micro-network of nanopillars
No full textEnhanced water collection through a periodic array of tiny holes in dropwise condensation
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