Periodic Reporting for period 4 - Liquid2DM (Two-dimensional liquid cell dielectric microscopy)
Período documentado: 2024-04-01 hasta 2025-09-30
In the last decade, we pioneered the development of Scanning Dielectric Microscopy (SDM), succeeding in probing electric polarization properties of nano-objects and macromolecules as small as few tens of nanometers in size. We achieved that by using the scanning probe microscopy approach – using a nanosized scanning tip as a probe - and through a series of instrumental breakthroughs, which pushed the spatial resolution of standard dielectric spectroscopy from micrometer scale down to the nanoscale. The challenge is now to push the technique down to the atomic level. This is exactly what this project will do.
The overall objective is to push the boundaries of SDM to probe electric polarization and electrodynamics properties of molecular liquids under confinement, with focus on water, electrolytic solutions and biologically relevant molecules, by implementing novel experimental and theoretical approaches. In particular, we will engineer 2D liquid cells made of van der Waals crystals by exploiting the most advanced 2D-materials technology, and we will directly probe the molecular liquids confined inside using the SDM scanning probe.
A new lab space dedicated to this project has been set up, where the two newly developed setups have been installed. They have been designed for the study of dielectric polarization and conductive properties of nanoconfined liquids and molecules. Their construction has been completed and they are now fully operational, as planned, 2D liquid cells made of various 2D crystals were successfully fabricated by the team, by transferring and stacking 2D crystals and using microfabrication techniques. The team has successfully carried out dielectric microscopy experiments of these devices, reaching the first critical objectives of the action. In particular, the team has recently obtained new breakthrough results on confined water, being able to measure for the first time the dielectric properties and conductivity in the in-plane direction – a technical challenge not achieved before. While our previous study reveal confined water is non-polarizable in the out-of-plane direction with respect to the confining surfaces, our recent experiments found that it has enhanced in-plane polarizability and conductivity, reaching superionic levels at room temperature. These findings, published in Nature in October 2025 (see www.nature.com/articles/s41586-025-09558-y) indicate the emergence of a new, 2D water phase characterized by ferroelectric-like polarizability and superionic-like conductivity with profound implications for biology, chemistry and energy science. Our investigation continues, with new results expected to be obtained in the months to come.
The team has disseminated the results related to this action in several peer-review publications and invited talks at international workshops/conferences and on social media.
First results already obtained by the group provided experimental data that were much needed to understand water polarization/electrodynamic properties and water-mediated interactions. This is because despite the advances in atomistic simulations, theorists struggle to predict these properties. The experimental data produced by this action will be key to benchmark their models and theories. In turn, they will help our understanding of the physics of nanoconfined molecular liquids, which is important for developing novel devices for electrochemistry, energy storage and analytical applications.
After the disruptions of the Covid pandemic in the first part of the project, this is now progressing smoothly. We then expect to obtain important new experimental data on the electric polarization/dynamic properties of confined water and biomolecules, such as proteins and DNA, that are crucial in life sciences.