Seminar coming soon: Water confined in nanopores: What do we know about it and what is it good for?

10 June, 2021

Laser-ultrasound experiment on water-infiltrated nanoporous silicon (TUHH/DESY/Künsting)

 

Patrick Huber

(Hamburg University of Technology and Deutsches Elektronen-Synchrotron DESY)

Water confined in pores a few nanometers across plays a dominant role in many natural and technological processes ranging from clay swelling, frost heave, and catalysis via col-loidal stability and protein folding to transport across artificial nanostructures and bio-membranes. In nanoporous media the geometrical confinement and pore wall-fluid interactions as well as complex pore morphologies may significantly alter water’s physico-chemical equilibrium and non-equilibrium properties, causing, for example, the molecular structuring of the fluid, huge negative Laplace pressures in the liquid and changed shear viscosities.

In the first part of my talk I will present opto-fluidic, X-ray and neutron scattering experiments on capillarity-driven transport, self-diffusion dynamics of water and aqueous electrolytes in nanoporous solids [1, 2] as well on the interplay of water’s capillarity with the confining solids’ elasticity [3, 4]. The observations on the effective, porous-medium scale will be related to the single-nanopore fluid properties [2], also by resorting to computer simulations. In the second part of my talk I will exemplify that exploiting water’s peculiar nanofluidics in com-bination with self-organized porosity in solids offers an entirely novel design space for sustainable, active integrated materials with functional diversity. In particular, I will present porous materials with electrically switchable wettability and hydraulic permeability [5] as well as large electrochemo-mechanical actuation for potential applications in Lab-on-a-Chip fluidics, sensorics, water filtration and energy conversion [5,6].

 

 

 

 

 

 

References:

[1] Capillary rise of water in hydrophilic nanopores.S. Gruener and T. Hofmann and D. Wallacher and A.V. Kityk,P. Huber, Phys. Rev. E 79, 067301(2009).

[2] Dynamics of water confined in mesopores with variable surface interaction.A.Jani, M.Busch, J.B.Mietner, J.Ollivier, M.Appel, B.Frick, J.M.Zanotti, P. Huber, M. Fröba, D. Morineau. J. Chem.Phys.154, 094505 (2021).

[3] Elastic response of mesoporous silicon to capillary pressures in the pores.G.Y.Gor, L Bertinetti, N.Bernstein, T Hofmann, P.Fratzl, P.Huber, Appl. Phys. Lett. 106, 261901 (2015).

[4] Laser-excited elastic guided waves reveal the complex mechanics of nanoporous silicon.M. Thelen, N. Bochud, M. Brinker, C. Prada, P. Huber, Nat. Comm. (2021, in press).

[5] Switchable imbibition in nanoporous gold, Y. Xue,J. Markmann, H. Duan, J. Weissmüller, P. Huber, Nat. Comm.5, 4237 (2014).

[6] Giant electrochemical actuation in a nanoporous silicon-polypyrrole hybrid material. M. Brinker, G. Dittrich, C. Richert, P. Lakner, T. Krekeler, T.F. Keller, N. Huber, P. Huber. Sci. Adv. 6 eaba1483 (2020).