Created using only a camera flash and graphene oxide, smart materials move in response to changes in humidity
Using an off-the-shelf camera flash, researchers turned an ordinary sheet of graphene oxide into a material that bends when exposed to moisture. They then used this material to make a spider-like crawler and claw robot that move in response to changing humidity without the need for any external power.
“The development of smart materials such as moisture-responsive graphene oxide is of great importance to automation and robotics,” said Yong-Lai Zhang of Jilin University, China, and leader of the research team. “Our very simple method for making typical graphene oxides smart is also extremely efficient. A sheet can be prepared within one second.”
In the journal Optical Materials Express, from The Optical Society (OSA), the researchers reported that graphene oxide sheets treated with brief exposure to bright light in the form of a camera flash exhibited reversible bending at angles from zero to 85 degrees in response to switching the relative humidity between 33 and 86 percent. They also demonstrated that their method is repeatable and the simple robots they created have good stability.
Although other materials can change shape in response to moisture, the researchers experimented with graphene-based materials because they are incredibly thin and have unique properties such as flexibility, conductivity, mechanical strength and biocompatibility. These properties make graphene ideal for broad applications in various fields. For example, the material’s excellent biocompatibility could allow moisture-responsive graphene oxide to be used in organ-on-a-chip systems that simulate the mechanics and physiological response of entire organs and are used for drug discovery and other biomedical research.
Making a moisture-responsive material
Other groups have shown that graphene oxide can be made moisture responsive through a chemical reaction called reduction, which removes oxygen from molecules. In fact, the researchers previously demonstrated that both sunlight and UV light can induce the effect. However, these approaches were hard to precisely control and not very efficient.
The research team experimented with using a camera flash, which typically covers a broad spectral range, as a simple and effective way to create moisture-responsive graphene. A camera flash allowed the researchers to remove oxygen from, or reduce, just one side of a sheet of graphene oxide. When moisture is present, the reduced side of the graphene oxide absorbs fewer water molecules, causing the non-reduced side to expand and the sheet to bend toward the reduced side. If the material is then exposed to dry air, it flattens out.
The researchers found that keeping the flash about 20 to 30 centimeters away from the graphene oxide sheet was enough to selectively modify the top layer of the sheet without penetrating all the way through to the other side. The sheet also needs to be more than 5 microns thick to prevent it from being completely reduced by the flash exposure.
Graphene robots
To make a moisture-driven crawler, the researchers cut flash-treated graphene oxide into an insect shape with four legs. The free-standing crawler was about 1 centimeter wide and moved forward when humidity was increased. Switching the humidity off and on several times induced the crawler to move 3.5 millimeters in 12 seconds, with no external energy supply.
The researchers also made a claw shape by sticking together eight 5-by-1 millimeter ribbons of flash-treated graphene oxide in a star shape. When moisture was present, the claw closed within 12 seconds. It returned back to an open position after 56 seconds of exposure to dry air.
“These robots are simple and can be flexibly manipulated by changing the environmental humidity,” said Zhang. “These designs are very important because moving and capturing/releasing are basic functions of automated systems.”
Zhang added that integrating moisture-responsive graphene into a microchannel system connected to humidity controller could allow even more precise control and other types of robots or simple machines. The researchers are now working on ways to improve the control of the material’s bending and are experimenting with ways to gain more complex performance from robots made of moisture-responsive graphene oxide.
Learn more: Moisture-Responsive ‘Robots’ Crawl with No External Power Source
The Latest on: Graphene robots
[google_news title=”” keyword=”Graphene robots” num_posts=”10″ blurb_length=”0″ show_thumb=”left”]- Graphene at 20: why the ‘wonder material’ is finally coming goodon April 30, 2024 at 6:31 am
Strong, light and with amazing electronic properties, graphene has always been touted as the “wonder material”. But two decades after it was first isolated, James McKenzie believes the graphene is ...
- The shape-shifting underwater robot pioneering the depths of the seaon April 30, 2024 at 3:00 am
HERO-BLUE is a proof-of-concept robot, measuring 31.5 inches by 23.6 inches by 11.8 inches and weighing 24.9 pounds. It’s remotely controlled, but with its stereoscopic vision, the future could see ...
- Strong storms may bring flooding, strong winds to the South this weekendon April 20, 2024 at 4:18 am
Late Saturday and early Sunday morning, storms may remain strong for the Southeast and bring gusty winds that may cause damage. There is a higher concern for flash flooding from central Texas to ...
- Medical Device Maker Intuitive Beats Estimates on Strong Demand for Surgical Robotson April 18, 2024 at 9:52 am
(Reuters) - Intuitive Surgical beat Wall Street estimates for first-quarter profit and revenue on Thursday, riding on higher demand for its robots used in minimally invasive procedures. Investor ...
- Wafer-thin, stretchy and strong as steel: could ‘miracle’ material graphene finally transform our world?on April 13, 2024 at 6:30 pm
They called it graphene. Consisting of a single layer of carbon atoms arranged in a hexagonal pattern, it is one of the strongest materials ever made and, for good measure, it is a better ...
- Meet the Robots Slicing Your Barbecue Ribson April 9, 2024 at 6:00 am
In Denison, Iowa, a robot spends eight hours a day slicing apart hog carcasses at a plant owned by Smithfield Foods. It serves a dual purpose: producing more ribs for barbecues and smokers ...
- The Best Robot Vacuums for 2024on April 1, 2024 at 5:00 pm
To pick up pet hair, you need a robot vacuum with strong suction power. Most companies in this space advertise power in pascals (Pa), the metric unit of pressure, though iRobot doesn't always make ...
- The Best Robot Vacuumson October 8, 2023 at 3:15 am
April 2024 Robot vacuums are feats of engineering ... and their bots are still going strong. “Twice I had to completely open it up to clean out dust and dog hair that was preventing it from ...
- Graphene Exhibits the Potential to be Strong Catalyston March 14, 2023 at 5:00 pm
The Manchester team, in association with scientists from China and USA, performed a series of experiments to reveal that the non-flatness of graphene allows it to be a strong catalyst. Firstly, with ...
- Graphene Is So Yesterday — Meet Boropheneon April 9, 2019 at 5:08 pm
It wasn’t long ago that graphene seemed to take the science and ... especially conductive or particularly strong. Another surprising application could be hydrogen storage. Studies show that ...
via Google News and Bing News