Tag Archives: carbon nanotubes

E- textiles Control Home Appliances With The Swipe Of A Finger

Electronic textiles could allow a person to control household appliances or computers from a distance simply by touching a wristband or other item of clothing — something that could be particularly helpful for those with limited mobility. Now researchers, reporting in ACS Nano, have developed a new type of e-textile that is self-powered, highly sensitive and washable.

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E-textiles are not new, but most existing versions have poor air permeability, can’t be laundered or are too costly or complex to mass-produce. Chinese researchers Jiaona Wang, Hengyu Guo, Congju Li and coworkers wanted to develop an E-textile that overcomes all of these limitations and is highly sensitive to human touch.

The researchers made a self-powered triboelectric nanogenerator by depositing an electrode array of conductive carbon nanotubes on nylon fabric. To make the E-textile washable, they incorporated polyurethane into the carbon nanotube ink, which made the nanotubes firmly adhere to the fabric. They covered the array with a piece of silk and fashioned the textile into a wristband. When swiped with a finger in different patterns, the E-textile generated electrical signals that were coupled to computers to control programs, or to household objects to turn on lights, a fan or a microwave from across the room. The E-textile is breathable for human skin, washable and inexpensive to produce on a large scale, the researchers say.

Source: https://www.eurekalert.org/

Adaptive Materials

Engineers at the U.S. Army Research Laboratory (ARL) and the University of Maryland have developed a technique that causes a composite material to become stiffer and stronger on-demand when exposed to ultraviolet light. This on-demand control of composite behavior could enable a variety of new capabilities for future Army rotorcraft design, performance and maintenance.

ARL‘s Dr. Frank Gardea, a research engineer, said the focus of the research was on controlling how molecules interact with each other. He said the aim was to “have them interact in such a way that changes at a small size, or nanoscale, could lead to observed changes at a larger size, or macroscale.”

Dr. Bryan Glaz, chief scientist of ARL‘s Vehicle Technology Directorate said “an important motivation for this work is the desire to engineer new structures, starting from the nanoscale, to enable advanced rotorcraft concepts that have been proposed in the past, but were infeasible due to limitations in current composites. One of the most important capabilities envisioned by these concepts is a significantly reduced maintenance burden due to compromises we make to fly at high speeds”, he said. The reduced scheduled maintenance of future Army aviation platforms is an important technological driver for future operating concepts.

Army researchers imagine a rotorcraft concept, which represents reactive reinforcements that when exposed to ultraviolet light will increase the mechanical behavior on-demand. The engineers said control of mechanical behavior could potentially lead to increased aerodynamic stability in rotorcraft structures.

The enhanced mechanical properties with potentially low weight penalties, enabled by the new technique, could lead to nanocomposite based structures that would enable rotorcraft concepts that we cannot build today,” Glaz said.

The joint work, recently published in Advanced Materials Interfaces (DOI: 10.1002/admi.201800038), shows that these composite materials could become 93-percent stiffer and 35-percent stronger after a five minute exposure to ultraviolet light. The technique consists of attaching ultraviolet light reactive molecules to reinforcing agents like carbon nanotubes. These reactive reinforcing agents are then embedded in a polymer. Upon ultraviolet light exposure, a chemical reaction occurs such that the interaction between the reinforcing agents and the polymer increases, thus making the material stiffer and stronger.

ource: https://www.arl.army.mil/