American researchers are now aiming to use waves to produce energy by making use of contact electrification between a patterned plastic nanoarray and water.
In the journal Angewandte Chemie, they have introduced an inexpensive and simple prototype of a triboelectric nanogenerator that could be used to produce energy and as a chemical or temperature sensor.
The triboelectric effect is the build up of an electric charge between two materials through contact and separation – it is commonly experienced when removal of a shirt, especially in dry air, results in crackling. Zhong Lin Wang and a team at the Georgia Institute of Technology in Atlanta have previously developed a triboelectric generator based on two solids that produces enough power to charge a mobile telephone battery.
However, high humidity interferes with its operation. How could this technology work with waves in water? The triboelectric effect is not limited to solids; it can also occur with liquids. The only requirement is that specific electronic energy levels of two substances are close enough together. Water just needs the right partner – maybe a suitable plastic.
As a prototype, the researchers made an insulated plastic tank, whose lid and bottom contain copper foil electrodes. Their system is successful because the inside of the lid is coated with a layer of polydimethylsiloxane (PDMS) patterned with tiny nanoscale pyramids. The tank is filled with deionized water. When the lid is lowered so that the PDMS nanopyramids come into contact with the water, groups of atoms in the PDMS become ionized and negatively charged.
A corresponding positively charged layer forms on the surface of the water. The electric charges are maintained when the PDMS layer is lifted out of the water. This produces a potential difference between the PDMS and the water. Hydrophobic PDMS was chosen in order to minimize the amount of water clinging to the surface; the pyramid shapes allow the water to drop off readily. Periodic raising and lowering of the lid while the electrodes are connected to a rectifier and capacitor produces a direct current that can be used to light an array of 60 LEDs. In tests with salt water, the generator produced a lower output, but it could in principle operate with seawater.
The current produced decreases significantly as temperature increases, which could allow this device to be used as a temperature sensor. It also decreases when ethanol is added to the water, which suggests potential use of the system as a chemical sensor. By attaching probe molecules with specific binding partners, it may be possible to design sensors for biomolecules.
About the Author
Dr. Zhong Lin Wang is the Hightower Chair in Materials Science and Engineering and Regents' Professor at Georgia Tech. His research interests include oxide nanobelts and nanowires, nanogenerators, self-powered nanosystems, piezotronics and piezo-phototronics. His work has received multiple honors.
Author: Zhong Lin Wang, Georgia Institute of Technology, Atlanta (USA), http://www.nanoscience.gatech.edu/group/Current%20Members/Group%20Leader/Zhong%20Lin%20Wang.php
Title: Water-Solid Surface Contact Electrification and its Use for Harvesting Liquid Wave Energy
Angewandte Chemie International Edition, Permalink to the article: http://dx.doi.org/10.1002/anie.201307249
Zhong Lin Wang | Source: Angewandte Chemie
Further information: pressroom.angewandte.org
More articles from Life Sciences:
New insights into the immune system of the gastrointestinal tract
09.12.2013 | Helmholtz Zentrum München
Vibrational Molecular Pathology
09.12.2013 | Journal of Biophotonics
In power electronics systems bonded connections create the central electrical connections between adjoining surfaces.
The quality of these bonded connections is one of the main factors that determines the reliability and availability of drive systems in electric vehicles, and hence constitutes a major design challenge for German auto manufacturers aiming to electrify their vehicles.
Now the partners participating in the RoBE (Robust Bonds in ...
International team of scientists develops new feedback method for optimizing the laser pulse shapes used in the control of chemical reactions
In many ways, traditional chemical synthesis is similar to cooking. To alter the final product, you can change the ingredients or their ratio, change the method of mixing ingredients, or change the temperature or pressure of the environment of the ingredients.
Like an accomplished chef, chemists have become very skilled ...
A genetic defect protects mice from infection with influenza viruses
A new study published in the scientific journal PLOS Pathogens points out that mice lacking a protein called Tmprss2 are no longer affected by certain flu viruses.
The discovery was made by researchers from the Helmholtz Centre for Infection Research (HZI) in Braunschweig in collaboration with colleagues from Göttingen and ...
The Light: Global study gets underway with online user survey
Light has a fundamental impact on our sense of well-being and performance. In cooperation with Zumtobel, a supplier of lighting solutions, Fraunhofer IAO has launched a global user survey of lighting quality in offices. The objective is to identify the best lighting conditions for a variety of spaces and lighting ...
Quantum entanglement, a perplexing phenomenon of quantum mechanics that Albert Einstein once referred to as “spooky action at a distance,” could be even spookier than Einstein perceived.
Physicists at the University of Washington and Stony Brook University in New York believe the phenomenon might be intrinsically linked with wormholes, hypothetical features of space-time that in popular science fiction can provide a much-faster-than-light shortcut from one part of the universe to another.
But here’s the catch: One couldn’t actually ...
09.12.2013 | Materials Sciences
09.12.2013 | Life Sciences
09.12.2013 | Studies and Analyses
05.12.2013 | Event News
04.12.2013 | Event News
12.11.2013 | Event News