Pore Structure Characterization of Mesoporous/Microporous Materials by <sup>1</sup>H NMR Using Water as a Probe Molecule

Hansen, Eddy W.; Tangstad, Elisabeth; Myrvold, Elisabeth; Myrstad, Trond

doi:10.1021/jp9721964

Cited by 36 publications

(32 citation statements)

References 13 publications

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“…More severe freezing point depressions are normally explained as a result of compartmentalization (Petrov and Furo 2009). Cryo-porometry results are, however, confounded with the influence of water situated at void walls as this water freezes at lower temperatures than water in the centre of voids (Hansen et al 1997(Hansen et al , 2005. There is also the aforementioned strong effect of bonding (Berthold et al 1996;Zelinka et al 2012) and possibly also an effect of water being 'ordered' close to wood cell wall polymer surfaces (Matthews et al 2006).…”

Section: Green Wood and Fibre Saturationmentioning

confidence: 99%

A critical discussion of the physics of wood–water interactions

et al. 2012

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This paper reviews recent findings on wood-water interaction and puts them into context of established knowledge in the field. Several new findings challenge prevalent theories and are critically discussed in an attempt to advance current knowledge and highlight gaps. The focus of this review is put on water in the broadest concept of wood products, that is, the living tree is not considered. Moreover, the review covers the basic wood-water relation, states and transitions. Secondary effects such as the ability of water to alter physical properties of wood are only discussed in cases where there is an influence on state and/or transition.

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Section: Green Wood and Fibre Saturationmentioning

confidence: 99%

A critical discussion of the physics of wood–water interactions

et al. 2012

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“…The effects of ordered (Radhakrishnan et al, 2002b) and disordered pore structures have been explored, as well as the influence of excess bulk liquid (Brovchenko and Geiger, 2002). An improved model for simulating porous silica has been suggested by Hansen et al (Hansen et al, 1997b). It has been shown through molecular dynamics simulations that the freezing and melting behaviour of simple confined liquids is additionally related to the surface tensions between the pore walls and the confined liquid / solid (Alba-Simionesco et al, 2006).…”

Section: Surface Interactions At the Solid-liquid Interfacementioning

confidence: 99%

Nuclear magnetic resonance cryoporometry

2008

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Nuclear Magnetic Resonance (NMR) cryoporometry is a technique for non-destructively determining pore size distributions in porous media through the observation of the depressed melting point of a confined liquid. It is suitable for measuring pore diameters in the range 2 nm -1 µm, depending on the absorbate. Whilst NMR cryoporometry is a pertabative measurement, the results are independent of spin interactions at the pore surface and so can offer direct measurements of pore volume as a function of pore diameter. Pore size distributions obtained with NMR cryoporometry have been shown to compare favourably with those from other methods such as gas adsorption, DSC thermoporosimetry, and SANS. The applications of NMR cryoporometry include studies of silica gels, bones, cements, rocks and many other porous materials. It is also possible to adapt the basic experiment to provide structural resolution in spatially dependent pore size distributions, or behavioural information about the confined liquid.

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“…Important examples of such systems are water molecules enclosed in porous media like zeolites [3] or cements [4], or water molecules in hydration shells of proteins [5][6][7][8][9][10][11]. Specifically, the existence of two kinds of water in pores, free water in the center of the pore, and bound water near the pore surface, has been established by a variety of experimental techniques [3,[12][13][14][15][16][17][18][19][20][21][22]. Recently such surface and core water phases were observed by 1 H-MAS solid state NMR spectroscopy in mesoporous silica materials MCM-41 [23] and SBA-15 [24] with parallel arrangement of cylindrical pores [1].…”

Section: Introductionmentioning

confidence: 99%

Hydrogen Bonding of Water Confined in Controlled-Pore Glass 10-75 Studied by ¹H-Solid State NMR

Vyalikh¹,

Emmler²,

Grünberg³

et al. 2007

Zeitschrift Für Physikalische Chemie

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The adsorption of water in the mesoporous silica material with cylindrical pores of uniform diameter, Controlled Pore Glass 10-75 (CPG), was studied by 1H-MAS solid state NMR spectroscopy. From the NMR spectra it is evident that inside the mesopores of the silica different water environments exist, which are characterized by their individual chemical shift. All observed hydrogen atoms are either surface –SiOH groups or hydrogen bonded water molecules. It is found that there exist some stronger bound water molecules on the surface which are not removable even by heating at a vacuum pump. As a tentative assignment these water molecules are attributed to surface defects or inaccessible cavities in the CPG 10-75. At intermediate water filling levels, the principal signal is a single NMR line with continuously varying chemical shift. This finding is interpreted as the result of a radial water filling mechanism. That is, the filling of the pore grows from the pore surface towards the pore axis. Finally it is shown that water is a sensor for surface and structural inhomogeneity and that a coexistence of inner pore and outer bulk water exists in the system.

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Pore Structure Characterization of Mesoporous/Microporous Materials by ¹H NMR Using Water as a Probe Molecule

Cited by 36 publications

References 13 publications

A critical discussion of the physics of wood–water interactions

A critical discussion of the physics of wood–water interactions

Nuclear magnetic resonance cryoporometry

Hydrogen Bonding of Water Confined in Controlled-Pore Glass 10-75 Studied by ¹H-Solid State NMR

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Pore Structure Characterization of Mesoporous/Microporous Materials by 1H NMR Using Water as a Probe Molecule

Cited by 36 publications

References 13 publications

A critical discussion of the physics of wood–water interactions

A critical discussion of the physics of wood–water interactions

Nuclear magnetic resonance cryoporometry

Hydrogen Bonding of Water Confined in Controlled-Pore Glass 10-75 Studied by 1H-Solid State NMR

Contact Info

Product

Resources

About

Pore Structure Characterization of Mesoporous/Microporous Materials by ¹H NMR Using Water as a Probe Molecule

Hydrogen Bonding of Water Confined in Controlled-Pore Glass 10-75 Studied by ¹H-Solid State NMR