Novel intelligent material

Researchers from the Centre for Advanced 2D Materials (CA2DM) at the National University of Singapore (NUS) have created a new class of intelligent materials. It has the structure of a two-dimensional (2D) material, but behaves like an electrolyte – and could be a new way to deliver drugs within the body. Just like traditional electrolytes, these new “2D-electrolytes” dissociate their atoms in different solvents, and become electrically charged. Furthermore, the arrangement of these materials can be controlled by external factors, such as pH and temperature, which is ideal for targeted drug delivery. The 2D-electrolytes also show promise for other applications that require a material to be responsive to environmental changes, such as artificial muscles and energy storage. The team is led by Professor Antonio Castro Neto, Director of CA2DM, and comprised researchers from CA2DM, as well as the NUS Department of Physics, and the NUS Department of Materials Science and Engineering. The research was published in the journal Advanced Materials.

In materials science, a 2D material is a solid material that exists in a single layer of atoms. It can be thought of as an atomically-thin sheet that has a specific height and width, but effectively no depth, hence, it is essentially two-dimensional. On the other hand, an electrolyte is a substance that produces an electrically conducting suspension when dissolved in a solvent, such as water. The results from the NUS researchers show the first instance of materials that have both 2D structure and properties of electrolytes, with a particular trend to shapeshift their form reversibly in liquid medium. The NUS team achieved this feat by using organic molecules as reactive species to add different functionalities to 2D materials such as graphene and molybdenum disulfide (MoS2). The methods used by the researchers to create 2D-electrolytes are only a few possible examples among many potential options, making this discovery an exciting new research area to explore. A major breakthrough of this research was that the orientation of the 2D-electrolytes could reversibly change by tweaking the external conditions. Currently, the electrical repulsion between the surface charge in a 2D material leads to it be laid out in a flat sheet. By altering the pH, the temperature, or the ionic concentration of the suspensions, the NUS researchers demonstrated the ability of the 2D-electrolyte sheet to shapeshift and form scroll-like arrangements. These experimental results are supported by detailed theoretical analysis in which they explain the physical mechanism behind the scroll formation and stability.

Source: National University Singapore news release