Vitamin C is the key to protecting an exciting new nanomaterial

Researchers at Texas A & M University have discovered a simple and inexpensive way to prevent rapid degradation of materials, which could pave the way for many applications for a new class of nanomaterials called MXenes (or "Maxines") .

Two-dimensional MXene nanowires are promising in applications ranging from energy storage to water purification. However, the MXenes have an Achilles heel: they degrade quickly when they are left in the open air.

According to the Texas A & M team, the solution to this problem is to expose the MXenes to any product in the family of compounds best represented by a natural dietary supplement such as vitamin C.

"Thanks to these results, consumer-stable MXens become possible and MXene-based materials of technical quality can become a practical reality," the researchers wrote in an article for the next issue of the online journal. material.

Interesting properties

Discovered in 2011 by a team from the Drexel University, the MXenes are sheets of materials of a few atoms thick, composed mainly of layers of metals such as titanium, interwoven carbon and / or d & # 39; nitrogen.

Because of their nanothickness and the variety of elements that make them up (other nanomaterials like graphene contain only carbon), "these materials tend to have very interesting properties, such as a conductivity high electrical and catalytic activity, "said Dr. Micah Green. an associate professor who led the work and was appointed jointly to Artie McFerrin's Chemical Engineering Department and Texas A & M's Materials Science and Engineering Department.

Because of these properties, the MXenes have generated a lot of interest and enthusiasm in the research community, with potential applications in all fields, from batteries to electronic sensors.

"But a problem has appeared in the background," Green said. MXenes degrade or oxidize rapidly. "They fall apart and stop being nanosheets.This happens in a few days."

Although other researchers have discovered that techniques such as drying or freezing MXenes can delay their degradation, "they will not last for years yet," he said. "And nobody wants a material that does not have a long life."

Texas A & M addressed the problem through an interdisciplinary team of experts in nanomaterials, ceramics and polymers.

The other faculty members involved in the work are Dr. Miladin Radovic, Professor in the Department of Materials Science and Engineering, and Dr. Jodie Lutkenhaus, Associate Professor in the Department of Materials Science and Engineering and the Department of Chemical Engineering.

Towards a solution

The team finally discovered that exposing a typical MXene to a solution of sodium L-ascorbate prevented the leaf from degrading. In addition, several related compounds, including vitamin C, have also worked. According to Green, the effect lasts. He also noted that the team had made the discovery about a year ago and that the treated MXen were still stable.

To further investigate the phenomenon leading to improved stability, the team performed molecular dynamics simulations of interactions between MXenes and antioxidants. They discovered that ascorbate molecules seem to associate with MXene's nanoscale sheet, preventing it from interacting with water molecules and, therefore, protecting it from damage. l & # 39; oxidation.

The team is excited by the fact that "its method seems to work with a variety of different MXenes," Green said. the material The article focuses on the most common MXene (Ti3C2Tx), but other types of MXen are even more unstable. So much so that "people have doubted that these materials can ever find applications, and with this technique it could change." Researchers are currently exploring the stability of these additional MXenes using the same approach.

"We hope everyone who works on MXenes, including industry professionals, will use our technique to protect their materials," Green said.