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Seminar of Dr. Yarik Grosu
Seminar of Dr. Yarik Grosu "Turning molecular spring into nano-shock absorber: the effect of macroscopic morphology and crystal size on the dynamic hysteresis of water intrusion-extrusion into-from hydrophobic nanopores".
Abstract:
Controlling the pressure at which liquids intrude (wet) and extrude (dry) nanopore is of paramount importance for a broad range of applications, such as energy conversion, catalysis, chromatography, separation, ionic channels, and many more. To tune these characteristics, one typically acts on the chemical nature of the system or pore size. In this presentation, we propose an alternative route for controlling both intrusion and extrusion pressures via proper arrangement of the grains of nanoporous material and via crystal size. To prove the concept, dynamic intrusion-extrusion cycles for powdered and monolithic ZIF-8 Metal-Organic Framework were conducted by means of water porosimetry and in operando neutrons scattering. We report a drastic increase in intrusion-extrusion dynamic hysteresis when going from a fine powder to a dense monolith configuration, transforming an intermediate performance of ZIF-8 + water system (poor molecular spring) into a desirable shock-absorber with more than one order of magnitude enhancement of dissipated energy per cycle. The obtained results are supported by MD simulations and pave the way for an alternative methodology of tuning intrusion-extrusion pressure using solely macroscopic arrangement of nanoporous material.