Despite several decades of development, microfluidics lacks a sealing material that can be readily fabricated, leak-tight under high liquid water pressure, stable over a long time, and vacuum compatible. In this paper, we report the performances of a micro-scale processable sealing material for nanofluidic/microfluidics chip fabrication, which enables us to achieve all these requirements. We observed that micrometric walls made of SU-8 photoresist, whose thickness range from 35 μm to 135 μm, are at least leak-tight to 1.5 bars and up to 5.5 bars, exhibit no water porosity even after 2 months of aging, and are able to sustain under 10−5 mbar vacuum. This sealing material is therefore reliable and versatile for building microchips, part of which must be isolated from liquid water under pressure or vacuum. Moreover, the fabrication process we propose does not require the use of either aggressive chemicals or high-temperature or high-energy plasma treatment. It thus opens a new perspective to seal microchips with sensitive surfaces containing nanomaterials.

In the current days of energy crisis and climate warming people look - more than ever - for domestication of hydrogen as energy carrier, especially for mobile applications. The current hydrogen technologies – from production and storage to applications - have all significant drawbacks. Although a huge effort was devoted to development of electrolytic hydrogen production using renewable energy sources, and to improvement of noble metals-free proton exchange membranes, the storage of hydrogen remains the bottle-neck of hydrogen-based transportation. In the present talk I will first review the currently used methods of hydrogen storage (compression, liquefaction, hybrid cryo-compression), from the point of view of their effectiveness, cost, and safety, then I will focus on hydrogen storage by sorption. I will discuss the parameters the ideal storage medium should exhibit to allow storage with high volumetric and gravimetric densities at ambient temperature and moderate pressure. A particular emphasis will be put on storage by physisorption in nanoporous solids: MOFs and carbons. Recent numerical and experimental results of hydrogen adsorption in boron-substituted nanoporous carbons will be referred to in details.

The phase behavior of confined fluids adsorbed in nanopores differs significantly from their bulk counterparts and depends on the chemical and structural properties of the confining structures. In general, phase transitions in nanoconfined fluids are reflected in stepwise adsorption isotherms with a pronounced hysteresis. Here, we show experimental evidence and an in-silico interpretation of the reversible stepwise adsorption isotherm which is observed when methane is adsorbed in the rigid, crystalline metal− organic framework IRMOF-1 (MOF-5) [1]. In a very narrow range of pressures, the adsorbed fluid undergoes a structural and highly cooperative reconstruction and transition between low-density and high-density nanophases, as a result of the competition between the fluid−framework and fluid−fluid interactions. This mechanism evolves with temperature: below 110 K, a reversible stepwise isotherm is observed, which is a result of the bimodal distribution of the coexisting nanophases. This temperature may be considered as a critical temperature of methane confined to nanopores of IRMOF-1. Above 110 K, as the entropy contribution increases, the isotherm shape transforms to a common continuous S-shaped form [2] that is characteristic to a gradual densification of the adsorbed phase as the pressure increases. The other IRMOF structures have been also modeled and the results compared to the IRMOF-1 case. The density distribution shows symmetric structures which structural properties evolve in a function of uptake and temperature [3].