Phase transitions of adsorbates. III. Heat effects and dimensional changes in nonequilibrium temperature cycles

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TypeArticle
Journal titleJournal of Colloid and Interface Science
ISSN0021-9797
Volume38
Issue1
Pages7583; # of pages: 9
Subjectadsorption; porosity; phase transformations; low degree; Concrete
AbstractChanges in the dimensions and heat content of the porous, 96% silica glass-water system were determined as temperature was cycled between +5 degrees and -40 degrees C at a rate of 0.33 degrees C/min. The results are explained by the fact that the maximum experimentally realizable relative pressure, based on that of undercooled water, becomes less than unity below 0 degrees C and diminishes with declining temperature. As a result, the adsorbate content decreases by migration of water to the outer surface, where it freezes between 0 degrees and -8 degrees C. At lower temperatures (- 20 degrees C) water drains from the smaller capillaries into larger voids and solidifies. An account is given of the anomalies of the extension isosteres, including hysteresis. In contrast with previous studies, the results obtained with porous glass and organic adsorbates are similar to those of the glass-water system and can be explained by the same theory.
Publication date
LanguageEnglish
AffiliationNRC Institute for Research in Construction; National Research Council Canada
Peer reviewedNo
IdentifierDBR-RP-487
NRC number12014
2786
NPARC number20373814
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Record identifier2805cc51-771b-4744-b932-bead045b8d8e
Record created2012-07-23
Record modified2016-05-09
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