Flexible - Page 3

A team of researchers from Hong Kong Polytechnic University (PolyU) has developed sensors which can be sprayed directly onto flat or curved surfaces. The sensors, made from a hybrid of carbon black (CB), graphene, other conductive nano-scale particles, and polyvinylidene fluoride (PVDF), can be networked to extract rich real-time information on the health status of the structure being monitored.

The technology includes a sensor network with a number of the sprayed nanocomposite sensors and an ultrasound actuator to actively detect the health condition of the structure to which they are fixed. When the ultrasound actuator emits guided ultrasonic waves (GUWs), the sensors will receive and measure the waves. If damage is detected, such as a crack in the structure, propagation of GUWs will be interfered by the damage, leading to the wave scattering phenomena to be captured by the sensor network. The damage can then be characterised quantitatively and accurately.

Researchers at Zhejiang University in China have designed a graphene-based aerogel mimicking the structure of the "powdery alligator-flag" plant that could have potential for use in applications like flexible electronics.

The team drew inspiration from the stem structure of the powdery alligator-flag plant (Thalia dealbata), a strong, lean plant capable of withstanding harsh winds. The researchers used a bidirectional freezing technique that they previously developed to assemble a new type of biomimetic graphene aerogel that had an architecture like that of the plant's stem. When tested, the material supported 6,000 times its own weight and maintained its strength after intensive compression trials and was resilient. They also put the aerogel in a circuit with a LED and found it could potentially work as a component of a flexible device.

Researchers affiliated with UNIST have raised the possibility of in-situ human health monitoring by wearing a contact lens with built-in wireless smart sensors. Towards this end, the team made use of smart contact lens sensors with electrodes made of graphene sheets and metal nanowires.

The smart contact lens sensor could help monitor biomarkers for intraocular pressure (IOP), diabetes mellitus, and other health conditions. The research team expects that this research breakthrough could lead to the development of biosensors capable of detecting and treating various human diseases, and used as a component of next-generation smart contact lens-related electronic devices.

Researchers at The University of Alabama used graphene to fabricate a lighter car hood, as part of an attempt to reduce the weight of a Chevrolet Camaro. The new hood is made of a mixture of graphene and carbon fiber, as opposed to the original hood which is made of aluminum.

The hood is half the weight of the original hood, a crucial adjustment as a larger team of students work to turn the Camaro into a plug-in hybrid as part of a national contest called EcoCAR 3.

Researchers from the Daegu Gyeongbuk Institute of Science & Technology in Korea have used graphene to develop neural probes that are small, flexible and read brain signals clearly.

The probe consists of an electrode, which records the brain signal. The signal travels down an interconnection line to a connector, which transfers the signal to machines measuring and analyzing the signals. The electrode starts with a thin gold base. Attached to the base are tiny zinc oxide nanowires, which are coated in a thin layer of gold, and then a layer of conducting polymer called PEDOT. These combined materials increase the probe's effective surface area, conducting properties, and strength of the electrode, while still maintaining flexibility and compatibility with soft tissue.

Researchers from the University of Exeter have developed an innovative new memory using a hybrid of graphene oxide and titanium oxide. These devices are reportedly low cost and environmentally friendly to produce, and are also suited for use in flexible electronic devices such as 'bendable' mobile phone, computer and television screens, and even 'intelligent' clothing. These devices may also have the potential to offer a cheaper and more adaptable alternative to 'flash memory', which is currently used in many common devices.

The team stated: "Using graphene oxide to produce memory devices has been reported before, but they were typically very large, slow, and aimed at the 'cheap and cheerful' end of the electronics goods market. Our hybrid graphene oxide-titanium oxide memory is, in contrast, just 50 nanometres long and 8 nanometres thick and can be written to and read from in less than five nanoseconds—with one nanometre being one billionth of a metre and one nanosecond a billionth of a second."

Researchers from the Lodz University of Technology in Poland have designed a transparent, flexible cryogenic temperature sensor with graphene structures as sensing elements. Such sensors could be useful for any field that requires operating in low-temperatures, such as medical diagnostics, space exploration and aviation, processing and storage of food and scientific research.

The sensors were repeatedly cooled from room temperature to cryogenic temperature. Graphene structures were characterized using Raman spectroscopy. The observation of the resistance changes as a function of temperature indicates the potential use of graphene in the construction of temperature sensors. The temperature characteristics of the analyzed graphene sensors exhibit no clear anomalies or strong non-linearity in the entire studied temperature range (as compared to the typical carbon sensor).

Researchers from the University of Exeter have developed a new method for creating entire device arrays directly on the copper substrates used for commercial manufacture of graphene. Complete and fully-functional devices can then be transferred to a substrate of choice, such as silicon, plastics or even textiles.

This new approach is said to be cheaper, simpler and less time consuming than conventional ways of producing graphene-based devices, thus holding real potential to open up the use of cheap-to-produce graphene devices for a host of applications from gas and biomedical sensors to displays.

The Graphene Flagship's Italian partner CNR-ISOF has found that it is possible to use graphene to produce fully flexible NFC antennas. By combining material characterization, computer modelling and engineering of the device, the Graphene Flagship researchers designed an antenna that could exchange information with near-field communication devices such as a mobile phone, matching the performance of conventional metallic antennas.

The graphene-based NFC antennas are chemically inert, highly resistant to thousands of bending cycles and can be deposited on different standard polymeric substrates or silk tissues. The fully flexible graphene NFC device demonstrators were tested with a smartphone through the NFC reader App by the Graphene Flagship partner STMicroelectronics, showing good functionality whether flat or fixed on curved objects.

Scientists at the University of WisconsinMadison have looked into graphene-based microelectrocorticography (uECoG) arrays, used in neuroscience researcher, searching for possibilities to expand the use of the arrays in areas such as the research of stroke or epilepsy. Researchers at the University of Wisconsin-Milwaukee, Medtronic PLC Neuromodulation, the University of Washington, and Mahidol University in Bangkok, Thailand were also involved in this study.

The researchers see graphene as one of the most promising candidates for transparent neural electrodes, because the material has a UV to IR transparency of more than 90%, in addition to its high electrical and thermal conductivity, flexibility, and biocompatibility. That allows for simultaneous high-resolution imaging and optogenetic control, according to the team.