Abstract
In recent years, considerable progress has been made in the development of novel porous materials with controlled architectures and pore sizes in the mesoporous range1,2,3,4. An important feature of these materials is the phenomenon of adsorption hysteresis: for certain ranges of applied pressure, the amount of a molecular species adsorbed by the mesoporous host is higher on desorption than on adsorption, indicating a failure of the system to equilibrate. Although this phenomenon has been known for over a century, the underlying internal dynamics responsible for the hysteresis remain poorly understood5,6,7,8,9. Here we present a combined experimental and theoretical study in which microscopic and macroscopic aspects of the relaxation dynamics associated with hysteresis are quantified by direct measurement and computer simulations of molecular models. Using nuclear magnetic resonance techniques10,11,12,13,14 and Vycor porous glass15,16 as a model mesoporous system, we have explored the relationship between molecular self-diffusion and global uptake dynamics. For states outside the hysteresis region, the relaxation process is found to be essentially diffusive in character; within the hysteresis region, the dynamics slow down dramatically and, at long times, are dominated by activated rearrangement of the adsorbate density within the host material.
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References
Schüth, F., Sing, K. S. W. & Weitkamp, J. (eds). Handbook of Porous Solids (Wiley-VCH, Weinheim, 2002)
Kresge, C. T., Leonowicz, M. E., Roth, W. J., Vartuli, J. C. & Beck, J. S. Ordered mesoporous molecular sieves synthesized by a liquid-crystal template mechanism. Nature 359, 710–712 (1992)
Sing, K. S. W., Rouquerol, F. & Rouquerol, J. Adsorption by Powders and Solids (Academic, London, 1999)
Barton, T. J. et al. Tailored porous materials. Chem. Mater. 11, 2633–2656 (1999)
Gelb, L. D., Gubbins, K. E., Radhakrishnan, R. & Sliwinska-Bartkowiak, M. Phase separation in confined systems. Rep. Prog. Phys. 62, 1573–1659 (1999)
Kierlik, E., Monson, P. A., Rosinberg, M. L., Sarkisov, L. & Tarjus, G. Capillary condensation in disordered porous materials: Hysteresis versus equilibrium behavior. Phys. Rev. Lett. 87, 055701 (2001)
Bocquet, L., Charlaix, E., Ciliberto, S. & Crassous, J. Moisture-induced ageing in granular media and the kinetics of capillary condensation. Nature 396, 735–737 (1998)
Woo, H. J. & Monson, P. A. Phase behavior and dynamics of fluids in mesoporous glasses. Phys. Rev. E 67, 041207 (2003)
Wallacher, D., Kunzner, N., Kovalev, D., Knorr, N. & Knorr, K. Capillary condensation in linear mesopores of different shape. Phys. Rev. Lett. 92, 195704 (2004)
Kärger, J., Pfeifer, H. & Heink, W. Principles and application of self-diffusion measurements by nuclear magnetic resonance. Adv. Magn. Reson. 12, 2–89 (1988)
Callaghan, P. T. Principles of Nuclear Magnetic Resonance Microscopy (Clarendon, Oxford, 1991)
Beyea, S. D., Caprihan, A., Glass, S. J. & DiGiovanni, A. Nondestructive characterization of nanopore microstructure: Spatially resolved Brunauer-Emmett-Teller isotherms using nuclear magnetic resonance imaging. J. Appl. Phys. 94, 935–941 (2003)
Valiullin, R., Kortunov, P., Kärger, J. & Timoshenko, V. Concentration-dependent self-diffusion of liquids in nanopores: A nuclear magnetic resonance study. J. Chem. Phys. 120, 11804–11814 (2004)
Valiullin, R., Kortunov, P., Kärger, J. & Timoshenko, V. Concentration-dependent self-diffusion of adsorbates in mesoporous materials. Magn. Reson. Imaging 23, 209–214 (2005)
Levitz, P., Ehret, G., Sinha, S. K. & Drake, J. M. Porous Vycor glass: The microstructure as probed by electron microscopy, direct energy transfer, small-angle scattering, and molecular adsorption. J. Chem. Phys. 95, 6151–6161 (1991)
Kikkinides, E. S. et al. Combination of small angle scattering and three-dimensional stochastic reconstruction for the study of adsorption-desorption processes in Vycor porous glass. J. Chem. Phys. 112, 9881–9887 (2000)
Evans, R. Fluids adsorbed in narrow pores — phase-equilibria and structure. J. Phys. Condens. Matter 2, 8989–9007 (1990)
Sethna, J. P. et al. Hysteresis and hierarchies: dynamics of disorder-driven first-order phase transformations. Phys. Rev. Lett. 70, 3347–3350 (1993)
Fisher, D. S. Scaling and critical slowing down in random-field Ising systems. Phys. Rev. Lett. 56, 416–419 (1986)
Huse, D. A. Critical dynamics of random-field Ising systems with conserved order parameter. Phys. Rev. B 36, 5383–5387 (1987)
Kärger, J. & Ruthven, D. M. Diffusion in Zeolites and Other Microporous Solids (Wiley & Sons, New York, 1992)
Woo, H. J., Sarkisov, L. & Monson, P. A. Mean-field theory of fluid adsorption in a porous glass. Langmuir 17, 7472–7475 (2001)
Carslaw, H. S. & Jaeger, J. C. Conduction of Heat in Solids (Clarendon, Oxford, 1946)
Rajniak, P., Soos, M. & Yang, R. T. Unified network model for adsorption–desorption in systems with hysteresis. Am. Inst. Chem. Eng. J. 45, 735–750 (1999)
Lee, J. W., Shim, W. G. & Moon, H. Adsorption equilibrium and kinetics for capillary condensation of trichloroethylene on MCM-41 and MCM-48. Micropor. Mesopor. Mater. 73, 109–119 (2004)
Ogielski, A. T. & Huse, D. A. Critical behavior of the three-dimensional dilute Ising antiferromagnet in a field. Phys. Rev. Lett. 56, 1298–1301 (1986)
Dierker, S. B. & Wiltzius, P. Random-field transition of a binary liquid in a porous-medium. Phys. Rev. Lett. 58, 1865–1868 (1987)
Smarsly, B. et al. Microstructural characterization of polystyrene-block-poly(ethylene oxide)-templated silica films with cubic-ordered spherical mesopores. Langmuir 19, 7295–7301 (2003)
Levitz, P. Off-lattice reconstruction of porous media: critical evaluation, geometrical confinement and molecular transport. Adv. Colloid Interf. Sci. 77, 71–106 (1998)
Newman, M. E. J. & Barkema, G. T. Monte Carlo Methods in Statistical Physics (Oxford Univ. Press, Oxford, 1999)
Acknowledgements
Research on this project at the University of Massachusetts was supported by the National Science Foundation. R.V. and J.K. thank the German Science Foundation and the Alexander von Humboldt Foundation for support.
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Valiullin, R., Naumov, S., Galvosas, P. et al. Exploration of molecular dynamics during transient sorption of fluids in mesoporous materials. Nature 443, 965–968 (2006). https://doi.org/10.1038/nature05183
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DOI: https://doi.org/10.1038/nature05183
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