Water forced in hydrophobic nano-confinement: tunable solvent system
Water is the sustainable solvent of excellence but its high polarity limits the solubility of non-polar compounds. Confinement of water in hydrophobic pores alters its hydrogen bonding structure and related properties such as dielectric constant and solvation power. Whether this special state of confined water can be rendered useful in chemical processes is hitherto underexplored. The original idea of this project is to modulate water solvent properties through hydrophobic nano-confinement. Pressure is applied to force a heterogeneous mixture of poorly soluble molecules and water into hydrophobic nanopores of host material where the lowered polarity of water enhances dissolution. Decompression after reaction causes expulsion of the solution from the pores and spontaneous demixing of reaction products as water returns to its normal polar state.
Temporary dissolution enhancement during confinement is expected to be advantageous to chemical reaction and molecular storage. Development of dedicated hydrophobic nanoporous materials and research methodologies providing in situ characterization of confined water, solutes and host material using NMR, EIS, DRS, X-ray and neutron scattering under static and dynamic conditions are key aspects of this project. Nano-confined water offers a potential alternative to compression for storing CH4 and H2 gas, and opens new opportunities for green chemistry such as aqueous phase hydrogenation reactions which benefit from enhanced hydrogen solubility.
Unprecedented control in time and space over H2O solvation properties in a WATUSO system will enable new technologies with major scientific and societal impact. WATUSO will lead to new insights in water research and deliver new multi-diagnostic characterization tools. WATUSO could revolutionize chemical manufacturing and gas storage and the concept could spill over to many more solvent-based processes. WATUSO will contribute significantly to a greener, more sustainable chemical industry.