Unlocking the Potential of Self-Assembling Nanosheets for Sustainable Manufacturing
Key Highlights :
The potential of self-assembling nanosheets to revolutionize the development of functional and sustainable nanomaterials for electronics, energy storage, health and safety, and more is a breakthrough that has been decades in the making. A team led by Lawrence Berkeley National Laboratory (Berkeley Lab) has successfully developed a multipurpose, high-performance barrier material from self-assembling nanosheets, which could significantly extend the shelf life of consumer products and enable a sustainable manufacturing approach.
The challenge in harvesting nanoscience to create functional materials is that many small pieces need to come together so that the nanomaterial can grow large enough to be useful. While stacking nanosheets is one of the simplest ways to grow nanomaterials into a product, “stacking defects”—gaps between the nanosheets—are unavoidable when working with existing nanosheets or nanoplatelets.
The new nanosheet material overcomes the problem of stacking defects by skipping the serial stacked sheet approach altogether. Instead, the team mixed blends of materials that are known to self-assemble into small particles with alternating layers of the component materials, suspended in a solvent. To design the system, the researchers used complex blends of nanoparticles, small molecules, and block copolymer-based supramolecules, all of which are commercially available.
As the solvent evaporates, the small particles coalesce and spontaneously organize, coarsely templating layers, and then solidify into dense nanosheets. In this way, the ordered layers form simultaneously rather than being stacked individually in a serial process. The small pieces only need to move short distances to get organized and close gaps, avoiding the problems of moving larger “tiles” and the inevitable gaps between them.
The team’s experiments at Oak Ridge National Laboratory’s Spallation Neutron Source helped them understand the early, coarse stages of the blends’ self-assembly. Experiments at Argonne National Laboratory’s Advanced Photon Source mapped out how each component comes together, and quantified their mobilities and the manner in which each component moves around to grow a functional material. Transmission electron microscope experiments at Berkeley Lab’s Molecular Foundry showed that by the time the solvent had evaporated, a highly ordered layered structure of more than 200 stacked nanosheets with very low defect density had self-assembled on the substrates.
The new nanosheet material has great potential as a dielectric, an insulating “electron barrier” material commonly used in capacitors for energy storage and computing applications. In collaboration with researchers in Berkeley Lab’s Energy Technologies Area, the team demonstrated that when the material is used to coat porous Teflon membranes (a common material used to make protective face masks), it is highly effective in filtering out volatile organic compounds that can compromise indoor air quality. The researchers also showed that the material can be redissolved and recast to produce a fresh barrier coating.
Now that the team has successfully demonstrated how to easily synthesize a versatile, functional material for various industrial applications from a single nanomaterial, the researchers plan to fine-tune the material's properties for specific applications. This could lead to the development of a range of self-assembling nanosheet materials that could be used for everything from improving the performance of electronics to creating new packaging materials. With this breakthrough, the development of functional and sustainable nanomaterials could be radically accelerated, ushering in a new era of sustainable manufacturing.
