Health and Safety Considerations for 2-D Materials
Two-dimensional (2-D) materials are structures that have length and wide, but are so thin (just a few atoms in some cases) that they essentially have no depth. While technically not perfectly two-dimensional, 2-D materials, are in all essence...2-D.
What's the big deal?
To answer that, let's take a step back and look at how 2-D materials are typically made. In order to be that thin, most, if not all, true 2-D materials are nanomaterials. A nanomaterial is a material in which at least one dimension exists in the nanoscale (i.e., in the range of one to one-hundred nanometers). The most common way to get thin sheets of material is through exfoliation (imagine using extremely sticky tape and ripping the top layer of a stack of layers off). This is an important part, because it is well-documented that the synthesis method of 2-D nanomaterials contributes directly to their toxicity, and exfoliated materials tend to be more toxic than those prepared by other methods.
Again, why the big deal?
There are many different types of 2-D materials, including hexagonal boron nitride (hBN), transition metal dichalcogenides (TMDs), black phosopohous (phosphorene) (BP), and the most common graphene and graphed-related materials. It is becoming more important to assess and understand 2-D toxicity as these materials make their way into commercial production.
The majority of 2-D toxicity studies have focused on graphene (a single layer of carbon atoms arranged in a honeycomb pattern), because of its popularity and billing as the "wonder material." However, the other materials have been relatively overlooked. Although there have been some toxicity studies on hBN and minimally on BP, there is very little data related to establishing safety standards for 2-D materials.
This is really an important point for two reasons. First, the global graphene market is predicted to have a CAGR of greater than 40% through 2023, yielding an estimated $800 million. With this swell of capacity and growth in multiple industries, it is going to be paramount to ensure proper health and safety guidelines are in place for workers and consumers.
Second, other than graphene, in which studies are still limited, there is a dearth of evidence and data on the other 2-D materials, and these are just the ones that have been around long enough to be studied. The fascination in 2-D materials has yielded an ever-growing universe of materials including silicine, germanene, and stanene.
New methods and research in characterization and classification of 2-D materials are becoming even more important as the rapid pace of material development continues. It will be impossible to test every single material for toxicological effects and develop standards before mass commercialization; therefore, understanding how to compare risk among classes of materials will be the key to keeping pace.
Visit our website for more information about health and safety resources for 2-D materials.