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J Phys Condens Matter. 2013 Nov 20;25(46):465105. doi: 10.1088/0953-8984/25/46/465105. Epub 2013 Oct 17.

Structural characterization of water and ice in mesoporous SBA-15 silicas IV: partially filled cases for 86 Å pore diameter.

Author information

1
Department of Physics, Faculty of Science, Vali-e-Asr University of Rafsanjan, Iran.

Abstract

Previous papers in this series have involved the study of water/ice in a sample of a mesoporous SBA-15 silica with a pore size of 86 Å, filling-factors f of 1.15 and 0.95. The present paper extends the study to partially filled samples with f = 0.6 and 0.4. It is found that the ice formed in the pores has characteristics that differ markedly from those seen in the previous measurements. For f = 0.6, there is a significant amount of hexagonal ice, as seen by the presence of the normal ice triplet. For f = 0.4, the triplet peaks are not seen, indicating the predominant formation of cubic ice superimposed on a broad diffuse scattering peak that is attributed to a defective form of low-density amorphous ice. A parameter-fitting routine has been used (as previously) to extract the variation of the peak intensities and shapes with temperature. A separate component analysis procedure confirms these conclusions and emphasizes the role of plastic ice in the phase conversion process for the 260-200 K temperature region. A comparison of the liquid phase data for filling-factors of 0.4 and 0.95 indicates that the structural characteristics of the water vary according to the thickness of the layer, as suggested by computer predictions.

PMID:
24132016
DOI:
10.1088/0953-8984/25/46/465105
[Indexed for MEDLINE]

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