How To Draw Electricity from the Bloodstream

Men build dams and huge turbines to turn the energy of waterfalls and tides into electricity. To produce hydropower on a much smaller scale, Chinese scientists have now developed a lightweight power generator based on carbon nanotube fibers suitable to convert even the energy of flowing blood in blood vessels into electricity.

For thousands of years, people have used the energy of flowing or falling water for their purposes, first to power mechanical engines such as watermills, then to generate electricity by exploiting height differences in the landscape or sea tides. Using naturally flowing water as a sustainable power source has the advantage that there are (almost) no dependencies on weather or daylight. Even flexible, minute power generators that make use of the flow of biological fluids are conceivable. How such a system could work is explained by a research team from Fudan University in Shanghai, China. Huisheng Peng and his co-workers have developed a fiber with a thickness of less than a millimeter that generates electrical power when surrounded by flowing saline solution—in a thin tube or even in a blood vessel.

The construction principle of the fiber is quite simple. An ordered array of carbon nanotubes was continuously wrapped around a polymeric core. Carbon nanotubes are well known to be electroactive and mechanically stable; they can be spun and aligned in sheets. In the as-prepared electroactive threads, the carbon nanotube sheets coated the fiber core with a thickness of less than half a micron. For power generation, the thread or “fiber-shaped fluidic nanogenerator” (FFNG), as the authors call it, was connected to electrodes and immersed into flowing water or simply repeatedly dipped into a saline solution. “The electricity was derived from the relative movement between the FFNG and the solution,” the scientists explained. According to the theory, an electrical double layer is created around the fiber, and then the flowing solution distorts the symmetrical charge distribution, generating an electricity gradient along the long axis.

The power output efficiency of this system was high. Compared with other types of miniature energy-harvesting devices, the FFNG was reported to show a superior power conversion efficiency of more than 20%. Other advantages are elasticity, tunability, lightweight, and one-dimensionality, thus offering prospects of exciting technological applications. The FFNG can be made stretchable just by spinning the sheets around an elastic fiber substrate. If woven into fabrics, wearable electronics become thus a very interesting option for FFNG application. Another exciting application is the harvesting of electrical energy from the bloodstream for medical applications. First tests with frog nerves proved to be successful.

The findings are published in  the journal Angewandte Chemie.

Source: http://newsroom.wiley.com/

Smart Textile Senses And Moves Like A Muscle

The ARC Center of Excellence for Electromaterials Science (ACES – Australia) researchers have for the first time, developed a smart textile from carbon nanotube and spandex fibres that can both sense and move in response to a stimulus like a muscle or joint.

Lead researcher Dr Javad Foroughi explains that the key difference between this, and previous ACES work, is the textile’s dual functionality.

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We have already made intelligent materials as sensors and integrated them into devices such as a knee sleeve that can be used to monitor the movement of the joint, providing valuable data that can be used to create a personalised training or rehabilitation program for the wearer,” Dr Foroughi said. “Our recent work allowed us to develop smart clothing that simultaneously monitors the wearer’s movements, senses strain, and adjusts the garment to support or correct the movement,” he adds.

The smart textile, which is easily scalable for the fabrication of industrial quantities, generates a mechanical work capacity and a power output which higher than that produced by human muscles. It has many potential applications ranging from smart textiles to robotics and sensors for lab on a chip devices. The team, having already created the knee sleeve prototype, is now working on using the smart textile as a wearable antenna, as well as in other biomedical applications.

Source: http://www.electromaterials.edu.au/