Our progress has been rather remarkable, exceeding our expectations. The project results have been reported in high-profile open access publications including 20 Nature and Science group publications, demonstrating the significant impact and quality of our research outcomes.
First, we found that many 2D materials can be highly transparent for protons but remain impermeable for all gases and liquids (Nature Nano 2019, Nature Communications 2019a). Clean-energy technologies based on hydrogen are built around membranes that require such selective properties. We found that 2D crystals, especially monolayers of mica, offer superior performance compared to existing materials. This work has attracted considerable industrial interest, with several companies exploring licensing opportunities for fuel cell applications.
Second, we established fundamental limits on gas permeability of 2D crystals. Despite being only one atom thick, monolayers of graphene or boron nitride are found to be so highly impermeable that it would take the lifetime of the Universe for a gas atom to pierce them under ambient conditions (Nature 2020a). This finding has important implications for barrier applications and gas separation technologies.
Third, we addressed water condensation inside small pores, which is responsible for many phenomena including friction, adhesion, lubrication and corrosion. Under typical ambient humidity of 30-50%, pores must be of true atomic scale to cause water condensation. We created 2D empty spaces from one to a few atoms in height and studied capillary condensation inside them (Nature 2020b), providing new fundamental understanding of nanoscale-fluid behavior.
Fourth, we reported several new electron transport phenomena in graphene-based vdW heterostructures (Nature 2020c, Nature 2021, Nature Electronics 2019, Nature Communications 2019b, 2020a-b, 2021), advancing our understanding of quantum transport.
