Navigation Links
Triboelectric generator produces electricity by harnessing friction between surfaces
Date:7/9/2012

Researchers have discovered yet another way to harvest small amounts of electricity from motion in the world around us this time by capturing the electrical charge produced when two different kinds of plastic materials rub against one another. Based on flexible polymer materials, this "triboelectric" generator could provide alternating current (AC) from activities such as walking.

The triboelectric generator could supplement power produced by nanogenerators that use the piezoelectric effect to create current from the flexing of zinc oxide nanowires. And because these triboelectric generators can be made nearly transparent, they could offer a new way to produce active sensors that might replace technology now used for touch-sensitive device displays.

"The fact that an electric charge can be produced through this principle is well known," said Zhong Lin Wang, a Regents professor in the School of Materials Science and Engineering at the Georgia Institute of Technology. "What we have introduced is a gap separation technique that produces a voltage drop, which leads to a current flow, allowing the charge to be used. This generator can convert random mechanical energy from our environment into electric energy."

The research was funded by the National Science Foundation, the Department of Energy and the U.S. Air Force. Details were reported in the June issue of the journal Nano Letters. In addition to Wang, authors of the paper included Feng-Ru Fan, Long Lin, Guang Zhu, Wenzhuo Wu and Rui Zhang from Georgia Tech. Fan is also affiliated with the State Key Laboratory of Physical Chemistry of Solid Surfaces at Xiamen University in China.

The triboelectric generator operates when a sheet of polyester rubs against a sheet made of polydimethysiloxane (PDMS). The polyester tends to donate electrons, while the PDMS accepts electrons. Immediately after the polymer surfaces rub together, they are mechanically separated, creating an air gap that isolates the charge on the PDMS surface and forms a dipole moment.

If an electrical load is then connected between the two surfaces, a small current will flow to equalize the charge potential. By continuously rubbing the surfaces together and then quickly separating them, the generator can provide a small alternating current. An external deformation is used to press the surfaces together and slide them to create the rubbing motion.

"For this to work, you have to use to two different kinds of materials to create the different electrodes," Wang explained. "If you rub together surfaces made from the same material, you don't get the charge differential."

The technique could also be used to create a very sensitive self-powered active pressure sensor for potential use with organic electronic or opto-electronic systems. The force from a feather or water droplet touching the surface of the triboelectric generator produces a small current that can be detected to indicate the contact. The sensors can detect pressure as low as about 13 millipascals.

Because the devices can be made approximately 75 percent transparent, they could potentially be used in touch screens to replace existing sensors. "Transparent generators can be fabricated on virtually any surface," said Wang. "This technique could be used to create very sensitive transparent sensors that would not require power from a device's battery."

While smooth surfaces rubbing together do generate charge, Wang and his research team have increased the current production by using micro-patterned surfaces. They studied three different types of surface patterning lines, cubes and pyramids and found that placing pyramid shapes on one of the rubbing surfaces generated the most electrical current: as much as 18 volts at about 0.13 microamps per square centimeter.

Wang said the patterning enhanced the generating capacity by boosting the amount of charge formed, improving capacitance change due to the air voids created between the patterns, and by facilitating charge separation.

To fabricate the triboelectric generators, the researchers began by creating a mold from a silicon wafer on which the friction-enhancing patterns are formed using traditional photolithography and either a dry or wet etching process. The molds, in which the features of the patterns are formed in recess, were then treated with a chemical to prevent the PDMS from sticking.

The liquid PDMS elastomer and cross-linker were then mixed and spin-coated onto the mold, and after thermal curing, peeled off as a thin film. The PDMS film with patterning was then fixed onto an electrode surface made of indium tin oxide (ITO) coated with polyethylene terephthalate (PET) by a thin PDMS bonding layer. The entire structure was then covered with another ITO-coated PET film to form a sandwich structure.

"The entire preparation process is simple and low cost, making it possible to be scaled up for large scale production and practical applications," Wang said.

The generators are robust, continuing to produce current even after days of use and more than 100,000 cycles of operation, Wang said. The next step in the research will be to create systems that include storage mechanisms for the current generated.

"Friction is everywhere, so this principle could be used in a lot of applications," Wang added. "We are combining our earlier nanogenerator and this new triboelectric generator for complementary purposes. The triboelectric generator won't replace the zinc oxide nanogenerator, but it has its own unique advantages that will allow us to use them in parallel."


'/>"/>

Contact: John Toon
jtoon@gatech.edu
404-894-6986
Georgia Institute of Technology Research News
Source:Eurekalert  

Related biology technology :

1. Ultra-fast photodetector and terahertz generator
2. A new imaging system produces 3-D models of monuments using unmanned aircraft
3. New magnetic yeast marks step toward harnessing Natures magnetic capabilities
4. Penn and Brown researchers demonstrate earthquake friction effect at the nanoscale
5. Slippery when stacked: NIST theorists quantify the friction of graphene
6. Innovative MetaMorph® NX Software Shatters Barriers Between Researchers and Image Analysis Goals with Exclusive Visual Workflow
7. EveryDayMatters.com Aims to Raise Awareness and Coordinate Care Between Mental and Physical Health
8. Researchers Find Potential Link Between Drinking Alcohol And Breast Cancer
9. Collaboration between Sanofi and Joslin Diabetes Center to focus on new drugs for diabetes
10. How ion bombardment reshapes metal surfaces
Post Your Comments:
*Name:
*Comment:
*Email:
Related Image:
Triboelectric generator produces electricity by harnessing friction between surfaces
(Date:2/10/2016)... 10, 2016  Matchbook, Inc., a company specializing ... biotech companies, announced today the appointment of ... Jim brings nearly 25 years of experience in ... spent nearly two decades in executive level roles ... at Genzyme and, most recently headed global logistics ...
(Date:2/10/2016)... NY (PRWEB) , ... February 10, 2016 , ... LATHAM, ... packages at the SPIE Photonics West conference in San Francisco’s Moscone Center ... 14 in the same venue. , These latest InGaAs PIN diode standard packages ...
(Date:2/10/2016)... ... February 10, 2016 , ... ... Microsoft Azure. On Azure, Arvados provides capabilities for managing and processing genomic and ... Microsoft Azure from major institutions collecting and analyzing genomic data,” said Adam Berrey ...
(Date:2/10/2016)... ... February 09, 2016 , ... Creation Technologies, leading global ... Highest Overall Customer Rating Award from Circuits Assembly , today announced its milestone ... USA, Canada, Mexico and China. , The EMS provider, known in the EMS ...
Breaking Biology Technology:
(Date:2/11/2016)... , Feb. 11, 2016  According to new research ... mainstream. More than 200 fingerprint, iris, and eye-vein ... under 70 brand names. This includes market leaders ... ZTE. Acuity projects that 600 million biometric smartphones ... global installed base. Maxine Most , ...
(Date:2/11/2016)... , Feb. 11, 2016  Vigilant Solutions announces today that ... are being used by Lee,s Summit ... recent location and arrest of a homicide suspect. ... covers around 65 square miles and is home to ... Department has a single mobile license plate reader system and ...
(Date:2/10/2016)... PUNE, India , February 10, 2016 ... --> According to 2016 iris ... fingerprint identification iris recognition is more widely ... are available with both fingerprint and iris ... allows the user to avoid purchasing two ...
Breaking Biology News(10 mins):