The team’s research themes are at the interface between soft matter, fluid dynamics and nanosciences. It combines experiments, theory and numerical modelling to explore transport mechanisms at the interfaces, from macroscopic to molecular scales. Her recent activities focus in particular on Nanofluidics i.e. the nano-fluidic transport in nanopores, nanotubes, 2D materials, and aim to highlight the sometimes exotic properties of transport at these ultimate scales. She also explores mechanical properties at nanoscale using atomic force microscopes specifically developed in the laboratory. The unexpected phenomena that emerge at these scales make it possible to explore new avenues in the fields of energy and desalination. A start-up company, Sweetch Energy, has emerged from the team’s work in these subjects.

 

Lately the team has predicted a new quantum contribution to the solid-liquid friction force, that results from the coupling of water charge fluctuations to the electronic excitations within the solid. Eventually this new theory has rationalized the experimental observation of radius-dependent water slippage in carbon nanotube. More importantly this unravels a paradigm change for nanoscale hydrodynamics that the team is now exploring within an european projet “ERC Synergy n-aqua” shared with Mainz and Cambridge teams.

 

Our team is also interested in the practical applications of its nanofluidic discoveries. Working in particular on the development of atomic force microscopes (AFM) and the fabrication of membranes from 2D materials, we are transforming the understanding of nanometric scales into innovative, patented macroscopic devices to solve industrial and ecological problems.

 

Fluid dynamics are generally studied in the framework of classical physics. Yet, at a solid-liquid interface, a fluid becomes sensitive to the quantum dynamics of the solid’s electrons. For fluids flowing near atomically-smooth surfaces, this results, in particular, in a quantum contribution to the hydrodynamic friction and the generation of electric currents. Inside the team, these pheomena are studied both experimentally and theoretically.

 

“Fluctuation-induced quantum friction in nanoscale water flows”, N. Kavokine, M.-L. Bocquet and L. Bocquet, Nature 602, 84–90 (2022)

“Massive radius-dependent flow slippage in single carbon nanotubes ” E. Secchi, S. Marbach, A. Niguès, D. Stein, A. Siria and L. Bocquet, Nature 537 210 (2016)

Despite recent progress in artificial intelligence, modern computers still cannot compete with our brain, which sports an energy consumption orders of magnitude lower. Its functioning also wildly differs from that of electronic devices, as it uses water and ions to carry out computations – and not electrons. Very recent works – both theoretical and experimental – in the group have unveiled the existence of long-term memory phenomena in nanofluidics. We now build on these discoveries to design bio-inspired artificial systems capable of learning.

“Modeling of emergent memory and voltage spiking in ionic transport through angström-scale slits”, P. Robin, N. Kavokine, and L. Bocquet, Science, 373, 687–691 (2021)

Inexpensive, functional and atomically precise molecules could be the basis of future electronic devices, but integrating them into circuits is requiring the development of new ways to control the interface between molecules and electrodes. Experimentally the techniques are essentially the STM and AFM-nc in UHV. In our group we are using state-of-the-art ab initio simulation codes to design atomistic models of such complex interfaces, in close collaboration with STM teams.

In liquid water conditions, the role played by interface chemistry becomes preponderant at nanoscales and nanofluidic transport is a source of questions at the interface between quantum chemistry and condensed matter. Using ab initio dynamics methods to simulate the solvent water explicitly, we recently showed unexpected “reactive” quantum effects at the interface of 2D nanomaterials and water, such as the peculiar interaction of solvated OH- ions at the graphene surface or the facile dehydration of a graphene oxide sheet.

“Reaction of Phthalocyanines with Graphene on Ir(111)”, Altenburg, S.J., Lattelais, M., Wang, B., Bocquet, M.-L., Berndt, R., Journal of the American Chemical Society, 137, 29 (2015)

“Spin in a Closed‐Shell Organic Molecule on a Metal Substrate Generated by a Sigmatropic Reaction”, Bocquet, M.-L., Lorente, N., Berndt, R., Gruber, M., Angewandte Chemie, 58, 821-824 (2019)

“Versatile electrification of two-dimensional nanomaterials in water”, Grosjean, B., Bocquet, M.-L., Vuilleumier, R., Nature
Communications, 10 (1), art. no. 1656 (2019)

“Structure and chemistry of graphene oxide in liquid water from first principles”, Mouhat, F., Coudert, F.-X., Bocquet, M.-L., Nature Communications, 11 (1), art. no. 1566 (2020)

Typical applications that arise from the fundamental study of nanofluidic transport merge with sustainable development and energy transition. Indeed, by taking advantage of nanoscales phenomena, the team developped innovatives water filtration and desalination processes which are efficient at macroscale. The team is also studying the scale-up of technologies for the production of energy from saline gradients (gradients present notably at the mouths of lakes and rivers). Each of these different applications is based on the use of nanostructured composite membranes inside advanced fluidics processes. These technologies has for goals to exploit new renewable energy sources and to develop innovatives systems for worldwide access to drinkable water, while presenting higher energy efficiency than conventional approaches.

“ Osmosis, from molecular insights to large scale applications”, S. Marbach and L. Bocquet, Chemical Society Reviews 48, 3102-3144 (2019)

“New avenues for the large scale harvesting of blue energy” A. Siria, M.-L. Bocquet and L. Bocquet, Nature Reviews Chemistry 1 0091 (2017)