Pore surface exploration by NMR

Strange, John H.; Mitchell, Jonathan; Webber, J. Beau W.

doi:10.1016/s0730-725x(03)00128-0

Cited by 62 publications

(61 citation statements)

References 19 publications

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“…FID and single spin echoes are suited to the former method, whereas spin echo trains are better acquired using the latter method. NMR cryoporometry experiments can also be performed using absorbates with bulk melting points above ambient temperature (Strange et al, 2003). This makes the experiment easier to perform and less costly without requiring the use of cryogens.…”

Section: The Nmr Cryoporometry Measurementmentioning

confidence: 99%

“…In recent work, octamethylcyclotetrasiloxane was seen to have a larger melting point depression constant than cyclohexane, potentially allowing access to pores of greater than 1 µm diameter . Naphthalene, used for super-ambient NMR cryoporometry with a bulk melting point of T ∞ m = 354 K, was determined to have a melting point depression constant of k GT = 181 K nm by NMR and DSC measurements (Strange et al, 2003). Octaphenylcyclotetrasiloxane has also been suggested for high-temperature NMR cryoporometry (T ∞ m = 473 K) although this has not yet been successfully demonstrated as a potential absorbate (Mitchell, 2003).…”

Section: Calibrationmentioning

confidence: 99%

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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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Section: The Nmr Cryoporometry Measurementmentioning

confidence: 99%

Section: Calibrationmentioning

confidence: 99%

Nuclear magnetic resonance cryoporometry

2008

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“…It has been shown elsewhere that water has a far stronger affinity to the surface in these silicas than nonpolar organic liquids 5 . This is because the silica surface contains hydroxyl groups to which the water molecules can form hydrogen bonds.…”

Section: Resultsmentioning

confidence: 92%

“…The most frequently used NMR technique has been relaxometry 3 . Although this method can provide estimates of the pore size distributions in the rocks 4 , it is highly sensitive to surface interactions 5 and can be difficult to interpret accurately 6 . Diffusion studies of flowing systems using NMR Pulsed Field Gradient (PFG) 7 measurements have shown how water can partially displace oil from rock pores.…”

Section: Introductionmentioning

confidence: 99%

Binary liquid mixtures in porous solids

Alnaimi

Mitchell

Strange

et al. 2004

The Journal of Chemical Physics

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The technique of Nuclear Magnetic Resonance (NMR) cryoporometry has been used to study the behaviour of binary liquid mixtures of water and decane in porous sol-gel silicas. The pore volume occupied by each liquid was measured as the ratio of water to decane was altered. It was observed that the water preferentially absorbed onto the silica surface and so was able to displace the decane from the pores. Water displaced the decane first from the smallest pores with a higher surface to volume ratio. The addition of sufficient water to just overfill the silicas was seen to completely displace the decane already occupying the pores after twenty-four hours.2 List of Figures Figure 1 The cryoporometry melting curves of decane and water mixtures in 100Å Merck silica. The decane melting region is clearly separate from the water melting region. As the fraction of water increases the decane shifts from the pores into the bulk. Figure 2 The pore volume distributions for decane (top) and water (bottom) generated from the cryoporometry melting curves in Figure 1. It can be seen that water preferentially displaces decane from the smallest pores.

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“…Water can be frozen in narrower pores (cavities in biomacromolecules, RBC membrane, intracellular space or voids between primary particles of nanooxides) at lower temperature that can be described by the Gibbs-Thomson relation for the freezing point depression [18,24,[30][31][32][33] …”

Section: Tablementioning

confidence: 99%

Interaction of unmodified and partially silylated nanosilica with red blood cells

et al. 2007

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Abstract:Interaction of red blood cells (RBCs) with unmodified and partially (50%) silylated fumed silica A-300 (nanosilica) was studied by microscopic, XRD and thermally stimulated depolarisation current (TSDC) methods. Nanosilica at a low concentration C A−300 < 0.01 wt.% in buffered aqueous suspension is characterised by a weak haemolytic effect on RBCs. However, at C A−300 = 1 wt% all RBCs transform into shadow corpuscles because of 100% haemolysis. Partial (one-half) hydrophobization of nanosilica leads to reduction of the haemolytic effect in comparison with unmodified silica at the same concentrations. A certain portion of the TSDC spectra of the buffered suspensions with RBC/A-300 is independent of the amounts of silica. However, significant portions of the low-and high-temperature TSDC bands have a lower intensity at C A−300 = 1 wt% than that for RBCs alone or RBC/A-300 at C A−300 = 0.01 wt.% because of structural changes in RBCs. Results of microscopic and XRD investigations and calculations using the TSDC-and NMR-cryoporometry suggest that the intracellular structures in RBCs (both organic and aqueous components) depend on nanosilica concentration in the suspension.

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Pore surface exploration by NMR

Cited by 62 publications

References 19 publications

Nuclear magnetic resonance cryoporometry

Nuclear magnetic resonance cryoporometry

Binary liquid mixtures in porous solids

Interaction of unmodified and partially silylated nanosilica with red blood cells

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