Change search
CiteExportLink to record
Permanent link

Direct link
Cite
Citation style
  • apa
  • harvard1
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • Other style
More styles
Language
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf
NMR cryoporometry with octamethylcyclotetrasiloxane as a probe liquid. Accessing large pores
KTH, School of Chemical Science and Engineering (CHE), Centres, Industrial NMR Centre.
KTH, School of Chemical Science and Engineering (CHE), Centres, Industrial NMR Centre.
KTH, School of Chemical Science and Engineering (CHE), Centres, Industrial NMR Centre.ORCID iD: 0000-0002-0231-3970
2007 (English)In: Journal of Colloid and Interface Science, ISSN 0021-9797, E-ISSN 1095-7103, Vol. 305, no 2, 280-285 p.Article in journal (Refereed) Published
Abstract [en]

Octamethylcyclotetrasiloxane is presented and investigated as probe liquid for NMR cryoporometry or DSC-based thermoporometry. This compound which may imbibe into both hydrophilic and hydrophobic pores is shown to exhibit a melting point depression that is larger than that for other cryoporometric probe materials such as cyclohexane. The transverse relaxation time differs by more than three orders of magnitude between the solid and liquid states, separated by a sharp phase transition. Hence, as demonstrated in controlled pore glasses, octamethylcyclotetrasiloxane can provide pore size distributions for materials with pore sizes up to the micrometer range.

Place, publisher, year, edition, pages
2007. Vol. 305, no 2, 280-285 p.
Keyword [en]
Cryoporometry, DSC, Melting point, NMR, Phase transition, Pore size, Pore size distribution, Thermoporometry
National Category
Physical Chemistry
Identifiers
URN: urn:nbn:se:kth:diva-6453DOI: 10.1016/j.jcis.2006.09.054ISI: 000243122000011OAI: oai:DiVA.org:kth-6453DiVA: diva2:11171
Note
QC 20100924. Uppdaterad från In press till Published (20100924).Available from: 2006-11-29 Created: 2006-11-29 Last updated: 2017-12-14Bibliographically approved
In thesis
1. Phase transitions in porous media studied by NMR
Open this publication in new window or tab >>Phase transitions in porous media studied by NMR
2006 (English)Doctoral thesis, comprehensive summary (Other scientific)
Abstract [en]

This Thesis presents studies of phase transitions ocurring in porous media. The investigated phase transitions include melting/crystallization, surface pre-melting and liquid-liquid phase separation of binary mixtures. A combination of NMR techniques, already existing and newly developed and ranging from cryoporometry to elaborate self-diffusion and spin-relaxation experiments, was applied in order to detect and quantify the effect of finite size constraints on those phase transitions. By relating the results to physico-chemical models, the difference in behaviour with respect to that of bulk was exploited and related to pore morphology and surface properties in diverse porous systems.

NMR cryoporometry is based on the detection of the melting/freezing temperature shifts with respect to those in the bulk state to obtain mean pore size and pore size distribution. We extended the size range in which this can be done in porous matrices of both hydrophilic and hydrophobic nature to a 1 μm-600 nm upper limit. This was achieved by introducing two new probe liquids namely octamethylcyclotetrasiloxane (OMCTS) and zinc nitrate hexahydrate Zn(NO)3•H2O.

The thickness of the pre-molten surface layer that appears at the interface of frozen octamethylcyclotetrasiloxane (OMCTS) to the matrix in controlled porous glasses was quantified and modeled including its temperature and wall-curvature dependence. The results reveal that the layer thickness depends logarithmically on the deviation from the pore melting point, while for the largest pore investigated this turns into a power law with the exponent of –1/2. Diverse NMR techniques were used not only to detect solely the surface layer and the evolution of the surface melting, but also to distinguish the latter from the volume melting transition within the pores.

The morphologies of two nanostructured materials, sintered films of TiO2 nanoparticles and a mesoporous foam obtained by surfactant-templated synthesis, were investigated. These two porous matrices have very different structures but fall into the size range accessible by NMR cryopormetry and their characterization plays an important role in their future applications. They were studied by exploiting the difference between melting and freezing temperature shifts ΔTm and ΔTf, respectively, with respect to that of bulk. NMR cryoporometry was shown to be a suitable alternative and an excellent complement to other porosimetry techniques, namely mercury intrusion and gas sorption porosimetries to analyze the pore structure and pore size distribution because of the unique and model-independent access to information about pore shape. By combining NMR cryoporometry with NMR diffusion experiments holds great potential for accessing information about pore interconnectivity.

By diverse NMR techniques we provided experimental evidence that corroborate that liquid-liquid phase separation of a binary mixture imbibed in porous media actually occurs within the individual pores. The size distribution of the phase-separated domains was measured.

Place, publisher, year, edition, pages
Stockholm: KTH, 2006. x, 50 p.
Series
Trita-FYK, 0603
National Category
Physical Chemistry
Identifiers
urn:nbn:se:kth:diva-4197 (URN)987-91-7178-526-8 (ISBN)
Public defence
2006-12-08, Sal D3, KTh, Lindstedtsvägen 5, Stockholm, 13:00
Opponent
Supervisors
Note
QC 20100927Available from: 2006-11-29 Created: 2006-11-29 Last updated: 2010-09-27Bibliographically approved

Open Access in DiVA

No full text

Other links

Publisher's full text

Authority records BETA

Furó, István

Search in DiVA

By author/editor
Vargas-Florencia, DulcePetrov, OlegFuró, István
By organisation
Industrial NMR Centre
In the same journal
Journal of Colloid and Interface Science
Physical Chemistry

Search outside of DiVA

GoogleGoogle Scholar

doi
urn-nbn

Altmetric score

doi
urn-nbn
Total: 183 hits
CiteExportLink to record
Permanent link

Direct link
Cite
Citation style
  • apa
  • harvard1
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • Other style
More styles
Language
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf