Adsorption-Induced Deformation, Fluid Transport and Rheology of Liquids in Nanoporous Materials

 

The advent of tailorable nanoporous materials, most prominently nanoporous silica glass, silicon, and gold allows one to explore the adsorption, rheology and transport of liquids in well-defined model geometries [1]. However, also the interaction of the fluids with the porous media and the resulting deformation on the nanoscopic, single-pore and on the macroscopic, porous-medium scale can be explored in detail. In my talk I will present experimental studies on evaporation, on fluid sorption-induced deformation [2] and on the capillarity-driven flow of liquids in extreme spatial confinement [3. The building blocks of the fluids investigated is varied from simple hydrocarbons to liquid crystals, polymers, and water. The rheology of the liquids is related to those of the bulk systems. Some attention is also paid to the external control of both sorption-induced deformation as well as the imbibition phenomenology by external stimuli, in particular by external hydraulic pressures [4] and electrical potentials [5].

[1] P. Huber: Soft matter in hard confinement: phase transition thermodynamics, structure, texture, diffusion and flow in nanoporous media. Journal of Physics: Condensed Matter 27, 103102 (2015).
[2] G.Y. Gor, P. Huber, J. Weißmüller: Elastocapillarity in nanopores: Sorption strain from the actions of surface tension and surface stress. Physical Review Materials 2 086002 (2018).
[3] S. Gruener, H. E. Hermes, B. Schillinger, S.U. Egelhaaf, P. Huber: Capillary rise dynamics of liquid hydrocarbons in mesoporous silica: Nano-rheology and determination of pore size distributions from the shape of imbibition front. Colloids and Surfaces A 496, 13 (2016).
[4] S. Gruener, D. Wallacher, S. Greulich, M. Busch, P. Huber: Hydraulic transport across hydrophilic and hydrophobic nanopores: Experiments with water and n-hexane. Physical Review E 93, 013102 (2016).
[5] Y. Xue, J. Markmann, H. Duan, J. Weissmüller, P. Huber: Switchable imbibition in nanoporous gold. Nature Communications 5, 4237 (2014).