Researchers from LG Electronics (LG) and Swiss university ETH Zurich (Swiss Federal Institute of Technology Zurich) have developed a method to greatly increase the speed and efficient transmission of gas, liquid and water vapor through perforated graphene, a material that has seen an explosion of scientific interest in recent years. The findings open up the possibility in the future to develop highly efficient filters to treat air and water.
Graphene, a versatile material composed of a one-atom thick layer of graphite, is the thinnest, lightest and strongest compound currently known to man. It was first successfully isolated in 2004 and since then much research has been conducted with sheets of graphene, which have the unique property of being the only material where each single atom is exposed to a chemical reaction from both sides due to its 2D structure. Reliability and consistency when working with extremely delicate graphene has been a constant challenge for researchers.
Scientists from ETH Zurich and LG developed a reliable method for creating 2D membranes using chemical vapor deposition (CVD) optimized to grow graphene with minimal defects and cracks to form graphene layers thinner than 1nm (nanometer). Using a focused ion beam (FIB), the researchers then drilled nanopores in double layers of graphene to produce porous membranes with aperture diameters between less than 10nm and 1µm (micrometer).
Testing various sized perforations, the researchers found that their graphene membrane resulted in water permeance five- to sevenfold faster than conventional filtration membranes and transmission of water vapor several hundred times higher compared to today’s most advanced breathable textiles such as Gore-Tex. The findings of the LG-ETH Zurich team could lead to the development in the future of highly breathable materials that are also waterproof and more effective filters to separate dangerous gases from the air.
The team’s research paper “Ultimate Permeation across Atomically Thin Porous Graphene” will be published today in Science, the academic journal of the American Association for the Advancement of Science, one of the world’s top scientific journals.