Phase engineering 2D materials for next-generation membrane technologies

2D material membranes allow the investigation of processes vital to the existence of life and provide a platform for developing next-generation nano filtration, purification, and healthcare technologies. Such membranes are formed by compacting flakes of, for example, graphene oxide or molybdenum disulphide (MoS2) into micrometre-thick membranes to create a network of fine capillaries. In addition to being used to control the transportation of water and other liquids, as we have recently demonstrated, it is possible to use an electric field applied across the membrane to turn water permeation on and off extremely quickly. Our early work has shown the essential role that structure and chemistry play in determining the behaviour of a particular 2D material for a particular application. For example, the carbon/oxygen ratio in graphene oxide membranes is critical to the transport of water although surprisingly this property and its effect on permeability are poorly understood. Knowledge of the exact mechanism through which an electric field can control permeation is also lacking with in situ experiments needed to allow monitoring of material and chemical changes. For MoS2 membranes, water transport can be reversibly controlled by using pH to change between the 2H and 1T' structural phases although it is unclear why. This project will help resolve these issues using the world-class facilities in the York Surface Science Laboratory, in particular, electron spectroscopy and scanning probe microscopy. Building on our recent high-profile work in the burgeoning field of 2D material membranes, we will provide key insight into fundamental nanofiltration processes that will accelerate the development of smart membrane technologies for artificial biological systems, tissue engineering, energy harvesting, and filtration. We will also expand the field by investigating nanoparticle interaction with 2D membranes which will open up applications in environmental remediation.