Recent Comments

    Category Chemistry/Nanotechnology

    ‘Bottlebrush’ Polymers make Dielectric Elastomers Increasingly Viable for use in Devices

    November 10, 2016, Categories  Technology/Electronics, Chemistry/Nanotechnology

    Electrical response of a circular diaphragm composed of a pure bottlebrush elastomer upon electroactuation with increasing voltage and without any external pre-strain. The numbers indicate the electric field-induced area expansion under constant-volume conditions at room temperature. Credit: Image courtesy of North Carolina State University

    Electrical response of a circular diaphragm composed of a pure bottlebrush elastomer upon electroactuation with increasing voltage and without any external pre-strain. The numbers indicate the electric field-induced area expansion under constant-volume conditions at room temperature. Credit: Image courtesy of North Carolina State University

    A multi-institutional team has developed a new electroactive polymer material that can change shape and size when exposed to a relatively small electric field. The advance overcomes two longstanding challenges regarding the use of electroactive polymers to develop new devices, opening the door to a suite of applications ranging from microrobotics to designer haptic, optic, microfluidic and wearable technologies.

    “Dielectric elastomers are the most respo...

    Read More

    Self-Healing Materials for Semi-Dry Conditions

    November 10, 2016, Categories  Technology/Electronics, Chemistry/Nanotechnology

    Chemical Structure of the Gels (A) Schematic representation of HPPRx and HPPul used in this study. (B) Chemical structures of the PRx-PB (x) gel, Pul-PB (x) gel, PRx-CC (x) gel, and pAAm (x) gel used in this study. Here, x represents the mol % content of cross-linker units in the vinyl polymerization.

    Chemical Structure of the Gels (A) Schematic representation of HPPRx and HPPul used in this study. (B) Chemical structures of the PRx-PB (x) gel, Pul-PB (x) gel, PRx-CC (x) gel, and pAAm (x) gel used in this study. Here, x represents the mol % content of cross-linker units in the vinyl polymerization.

    Before we have self-healing cars or buildings, we need strong materials that can fully self-repair in water-free environments. Self-healing materials work very well if they are soft and wet, but research groups have found that the ability to self-repair diminishes as materials dry out. Scientists at Osaka University are beginning to bridge this gap with rigid materials that can repair 99% of a cut on the surface in semi-dry conditions...

    Read More

    Toward a Hand-Held ‘Breathalyzer’ for Diagnosing Diabetes

    November 10, 2016, Categories  Chemistry/Nanotechnology, Biology/Biotechnology

    A portable and compact device is demonstrated for measuring acetone in breath samples. The device features a 7 cm long high finesse optical cavity as an optical sensor that is coupled to a miniature adsorption preconcentrator containing 0.5 g of polymer material. Acetone is trapped out of breath and released into the optical cavity where it is probed by a near-infrared diode laser operating at ∼1670 nm. With an optical cavity mirror reflectivity of 99.994%, a limit of detection of 159 ppbv (1σ) is demonstrated on samples from breath bags. Initial results on direct breath sampling are presented with a precision of 100 ppbv. The method is validated with measurements made using an ion–molecule reaction mass spectrometer. Data are presented on elevated breath acetone from two individuals following an overnight fast and exercise, and from a third individual during several days of routine behavior.

    A portable and compact device is demonstrated for measuring acetone in breath samples. The device features a 7 cm long high finesse optical cavity as an optical sensor that is coupled to a miniature adsorption preconcentrator containing 0.5 g of polymer material. Acetone is trapped out of breath and released into the optical cavity where it is probed by a near-infrared diode laser operating at ∼1670 nm. With an optical cavity mirror reflectivity of 99.994%, a limit of detection of 159 ppbv (1σ) is demonstrated on samples from breath bags. Initial results on direct breath sampling are presented with a precision of 100 ppbv. The method is validated with measurements made using an ion–molecule reaction mass spectrometer...

    Read More

    The Thinnest Photodetector in the World

    November 9, 2016, Categories  Physics, Technology/Electronics, Chemistry/Nanotechnology

    (top) Devices with one-layer and seven-layer MoS2 were built on top of a silicon base and compared. Dielectric constants responsible for the difference in electrostatic potentials are shown in parenthesis. (bottom) The device with one-layer MoS2 (inside the violet box) showed better performance in converting light to electric current than the seven-layer device (inside the pink box).

    (top) Devices with one-layer and seven-layer MoS2 were built on top of a silicon base and compared. Dielectric constants responsible for the difference in electrostatic potentials are shown in parenthesis. (bottom) The device with one-layer MoS2 (inside the violet box) showed better performance in converting light to electric current than the seven-layer device (inside the pink box).

    The Center for Integrated Nanostructure Physics, within the Institute for Basic Science (IBS) has developed the world’s thinnest photodetector, that is a device that converts light into an electric current. With a thickness of just 1.3nm – 10X smaller than the current standard silicon diodes – this device could be used in the Internet of Things IoT, smart devices, wearable electronics and photoelectronics.

    In ...

    Read More