Tag Archives: corrosion

Graphene Boosts Life Time Of Implantable Devices

The United States is seeing an increase in the number of neurological diseases. Stroke is ranked as the fifth leading cause of death, with Alzheimer’s being ranked sixth. Another neurological disease – Parkinson’s – affects nearly 1 million people in the U.S. each year. Implantable neurostimulation devices are a common way to treat some of these diseases. One of the most commonly used elements in these devices is platinum microelectrodes – but it is prone to corrosion, which can reduce the functional lifetime of the devices. Purdue University researchers have come up with a solution to help – they are adding a graphene monolayer to the devices to protect the microelectrodes.

I know from my industry experience that the reliability of implantable devices is a critical issue for translating technology into clinics,” said Hyowon “Hugh” Lee, an assistant professor in Purdue’s College of Engineering and a researcher at the Birck Nanotechnology Center, who led the research team. “This is part of our research focusing on augmenting and improving implantable devices using nano and microscale technologies for more reliable and advanced treatments. We are the first ones that I know of to address the platinum corrosion issue in neurostimulation microelectrodes.

Lee said he learned about the advantage of using graphene from his colleague at Birck Nanotechnology Center, Zhihong Chen, who is an expert in graphene technology. The team has shown the graphene monolayer to be an effective diffusion barrier and electrical conductor.

If you attempt to deliver more charge than the electrode can handle, it can corrode the electrode and damage the surrounding tissues,” Lee said. He also thinks that microscale electrodes are going to play a key role in the future with more demand for precise and targeted neurostimulation therapy. “We think neurosurgeons, neurologists, and other scientists in neuroengineering field will be able to use this electrode technology to better help patients with implantable devices for restoring eyesight, movement, and other lost functionalities.”

Lee and his team are working with the Purdue Research Foundation Office of Technology Commercialization on patenting and licensing the technology. They are looking for partners interested in licensing it.

The research has been published in the journal  2D Materials.

Source: https://www.purdue.edu/

Self-Healing Coating Protects Metals From Corrosion

It’s hard to believe that a tiny crack could take down a gigantic metal structure. But sometimes bridges collapse, pipelines rupture and fuselages detach from airplanes due to hard-to-detect corrosion in tiny cracks, scratches and dents. A Northwestern University team has developed a new coating strategy for metal that self-heals within seconds when scratched, scraped or cracked. The novel material could prevent these tiny defects from turning into localized corrosion, which can cause major structures to fail.

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Localized corrosion is extremely dangerous,” said Jiaxing Huang, who led the research. “It is hard to prevent, hard to predict and hard to detect, but it can lead to catastrophic failure.” Huang is a professor of materials science and engineering in Northwestern’s McCormick School of Engineering.

When damaged by scratches and cracks, Huang’s patent-pending system readily flows and reconnects to rapidly heal right before the eyes. The researchers demonstrated that the material can heal repeatedly — even after scratching the exact same spot nearly 200 times in a row.While a few self-healing coatings already exist, those systems typically work for nanometer- to micron-sized damages. To develop a coating that can heal larger scratches in the millimeter-scale, Huang and his team looked to fluid. “When a boat cuts through water, the water goes right back together,” Huang said. “The ‘cut’ quickly heals because water flows readily. We were inspired to realize that fluids, such as oils, are the ultimate self-healing system.” But common oils flows too readily, Huang noted. So he and his team needed to develop a system with contradicting properties: fluidic enough to flow automatically but not so fluidic that it drips off the metal’s surface.

The team met the challenge by creating a network of lightweight particles — in this case graphene capsules — to thicken the oil. The network fixes the oil coating, keeping it from dripping. But when the network is damaged by a crack or scratch, it releases the oil to flow readily and reconnect. Huang said the material can be made with any hollow, lightweight particlenot just graphene. “The particles essentially immobilize the oil film,” Huang said. “So it stays in place.”

The study was published  in Research, the first Science Partner Journal recently launched by the American Association for the Advancement of Science (AAAS) in collaboration with the China Association for Science and Technology (CAST).

Source: https://news.northwestern.edu/