Periodic Reporting for period 4 - CARBONICE (Carbon – Ice Composite Materials: Water Structure and Dynamics at the Carbon Interface)
Reporting period: 2021-12-01 to 2023-05-31
Carbon and water in its various states of matter make up a substantial proportion of our Universe. The two materials are highly dissimilar with respect to their chemical and physical properties. Elemental carbon is even often referred to as a hydrophobic, ‘water-hating’ material. Yet, the two materials often coexist and critical yet poorly understood processes take place at the interface between these unlike chemical species. This includes the hydration shells of hydrophobic moieties in biomolecules, clathrate hydrate materials where water molecules crystallise around hydrophobic guest species as well as icy comets which are often black due to the presence of carbon at their surfaces.
The aim of the CARBONICE project is to investigate the interface and interplay between water and carbon in detail. Using new and innovative experimental strategies, the water molecule will be placed in a variety of different yet highly relevant carbon environments. This will give us unprecedented insights into how water hydrates hydrophobic species which is highly important in the context of hydrophobic interactions. Investigations into how carbon species influence phase transitions of ice will give new insights into crystallisation phenomena but will also reveal the factors that lead to the formation of either ferro- or antiferroelectric ices. Creating carbon – ice composites in the lab as they exist on comets will enable us to understand the complex weather cycles on comets and may help explaining the unusual surface features recently identified by the Rosetta space probe.
In summary, this truly multidisciplinary project opens up a new spyhole to critically important processes at the water – carbon interface. The results will have an impact on the space, atmospheric and general materials sciences but will also be highly relevant with respect to further optimising the computer models of water as well as understanding the properties of water in nano-confinements and how it drives biological processes.
The aim of the CARBONICE project is to investigate the interface and interplay between water and carbon in detail. Using new and innovative experimental strategies, the water molecule will be placed in a variety of different yet highly relevant carbon environments. This will give us unprecedented insights into how water hydrates hydrophobic species which is highly important in the context of hydrophobic interactions. Investigations into how carbon species influence phase transitions of ice will give new insights into crystallisation phenomena but will also reveal the factors that lead to the formation of either ferro- or antiferroelectric ices. Creating carbon – ice composites in the lab as they exist on comets will enable us to understand the complex weather cycles on comets and may help explaining the unusual surface features recently identified by the Rosetta space probe.
In summary, this truly multidisciplinary project opens up a new spyhole to critically important processes at the water – carbon interface. The results will have an impact on the space, atmospheric and general materials sciences but will also be highly relevant with respect to further optimising the computer models of water as well as understanding the properties of water in nano-confinements and how it drives biological processes.
During this project, we developed new methods for mixing ‘water-hating’ carbon materials and ice - effectively making a comet in the lab. Using highly specialised neutron techniques, we studies the structure of water surrounding the carbon molecules. A plethora of diverse structures was discovered and we observed the onset of the often-discussed cross-over from small molecules towards water-repelling surfaces. Furthermore, we studied the effects of the carbon species on the phase transitions of the ice and the thermal desorption properties as it would be observed on comets. As part of our efforts to mix carbon species and ice, we found that ball-milling at low temperatures produces a new form of ice, medium-density amorphous ice, that may enable us to understand the many anomalies of liquid water in the future. Furthermore, we showed that ice can be a high-energy geophysical material under certain conditions. In addition to the work on carbon species, we showed that ammonium fluoride has an enormous impact on the phase transitions of ice and we also conducted detailed studies into the effects of acid and base dopants. In summary, this project has given new insights into the properties of the all-important H2O molecule in its condensed states and the effects other chemical species can have on ice. The results are important with respect to space research, the hydration of biomolecules and the formation of ice in clouds.
Several of the publications resulting from this project have progressed the field beyond the state of the art. The impacts of the various studies are diverse and affect the areas of space research, hydrophobic hydration, understanding the anomalies of liquid water, inducing disorder in materials with topological charges and clarified the nature of a new distorted crystalline form of ice which may have parallels with other classes of materials. The discovery of medium-density amorphous ice was entirely unexpected but will have a huge impact on our understanding of water and its many solid forms.