A study of freezing-melting hysteresis of water in different porous materials: Part II: surfactant-templated silicas
2011 (English)In: Physical Chemistry, Chemical Physics - PCCP, ISSN 1463-9076, E-ISSN 1463-9084, Vol. 13, no 36, 16358-16365 p.Article in journal (Refereed) Published
The freezing-melting hysteresis of water in mesoporous silicas MCM-48, MCM-41 and SBA-16 has been studied by NMR cryoporometry. The hysteresis in MCM-48 was found to exhibit nearly parallel branches, matching type H1 hysteresis that had been observed earlier in controlled pore glass. The same type of hysteresis is observed in two of three different-sized MCM-41 under study (a pore diameter of 3.6 and 3 nm), superimposed with a secondary, extremely broad, type H3 hysteresis. No hysteresis was found in the smallest MCM-41 with a pore diameter < 3 nm. Finally, water in SBA-16 exhibits type H2 hysteresis with the freezing branch being essentially steeper than the melting one, which is attributed to a pore blockage upon freezing, similar to what we observed earlier in Vycor porous glass. The data were analyzed using the model of curvature-dependent metastability of a solid phase upon melting; the validity of this model has been discussed.
Place, publisher, year, edition, pages
2011. Vol. 13, no 36, 16358-16365 p.
IdentifiersURN: urn:nbn:se:kth:diva-40690DOI: 10.1039/c1cp21902bISI: 000294441900030ScopusID: 2-s2.0-80053278011OAI: oai:DiVA.org:kth-40690DiVA: diva2:442340
FunderSwedish e‐Science Research CenterKnut and Alice Wallenberg Foundation
QC 201109212011-09-212011-09-202011-09-21Bibliographically approved