Graphene-enhanced ceramic tiles make striking art

In recent years, materials scientists experimenting with ceramics have started adding an oxidized form of graphene to the mix to produce ceramics that are tougher, more durable, and more resistant to fracture, among other desirable properties. Researchers at the National University of Singapore (NUS) have developed a new method that uses ultrasound to more evenly distribute graphene oxide (GO) in ceramics, according to a new paper published in the journal ACS Omega. And as a bonus, they collaborated with an artist who used the resulting ceramic tiles to create a unique art exhibit at the NUS Museum—a striking merger of science and art. As reported previously, graphene is the thinnest material yet known, composed of a single layer of carbon atoms arranged in a hexagonal lattice. That structure gives it many unusual properties that hold great promise for real-world applications: batteries, super capacitors, antennas, water filters, transistors, solar cells, and touchscreens, just to name a few. In 2021, scientists found that this wonder material might also provide a solution to the fading of colors of many artistic masterpieces. For instance, several of Georgia O'Keeffe's oil paintings housed in the Georgia O'Keeffe Museum in Santa Fe, New Mexico, have developed tiny pin-sized blisters, almost like acne, for decades. Conservators have found similar deterioration in oil-based masterpieces across all time periods, including works by Rembrandt. Van Gogh's Sunflower series has been fading over the last century due to constant exposure to light. A 2011 study found that chromium in the chrome yellow Van Gogh favored reacted strongly with other compounds like barium and sulfur when exposed to sunlight. A 2016 study pointed the finger at the sulfates, which absorb in the UV spectrum, leading to degradation. Even contemporary art materials are prone to irreversible color changes from exposure to light and oxidizing agents, among other hazards. That's why there has been recent work on the use of nanomaterials for conservation of artworks. Graphene has a number of properties that make it attractive for art-conservation purposes. The one-atom-thick material is transparent, adheres easily to various substrates, and serves as an excellent barrier against oxygen, gases (corrosive or otherwise), and moisture. It's also hydrophobic and is an excellent absorber of UV light.

Enter ultrasonication

Graphene oxide is a byproduct of making graphite oxide. Its unique properties have made it useful in such applications as conductive transparent coatings, flexible electronics, water electrolysis, water filtration and purification, biosensors, and as a targeted drug delivery agent. It can also serve as a reinforcing agent when added to ceramic (kaolin) slurries, resulting in enhanced mechanical properties. A key factor is the even dispersion of the graphene oxide in the matrix, usually achieved by mechanical mixing or high-shear mixing equipment. NUS materials scientist Daria Andreeva and co-authors found that applying low-frequency sound waves (ultrasonication) is an efficient method for uniform distribution of graphene sheets thanks to the cavitation it creates in the slurry. They conducted several experiments, adjusting the concentrations of graphene oxide and the ultrasonic exposure time to find the optimal conditions. The results: adding 0.5 weight percent of graphene oxide to the slurry and applying ultrasound for 10 minutes yields the best mechanical properties. Ultrasonication also improved the ease of processing and appearance of the resulting ceramic tiles. NUS artist-in-residence Delia Prvački adapted this research to create original works of art from the new ceramic material for the NUS Museum. She used high-speed cameras to visualize different preparation methods: ceramic tiles that were merely fired, those that were fired and sonicated, and those made using the optimal recipe. The latter tiles were more robust and durable—very well-suited for an art installation. The process also enables better control over surface textures for ceramic pieces with greater visual and tactile appeal. “We explored artistic potential by experimenting with novel ceramic forms and textures,” the authors wrote. “Harnessing the properties of graphene pushes the boundaries of traditional ceramic art, enabling the creation of delicate and intricate ceramic structures that were previously unattainable. This approach not only enhances the artistic possibilities but also can potentially reduce the need for structural elements.” ACS Omega, 2024. DOI: 10.1021/acsomega.4c05748  (About DOIs).