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Visualization of Freezing Process in situ upon Cooling and Warming of Aqueous Solutions.
- Source :
-
Scientific Reports . 12/12/2014, p1-6. 6p. - Publication Year :
- 2014
-
Abstract
- The freezing of aqueous solutions and reciprocal distribution of ice and a freeze-concentrated solution (FCS) are poorly understood in spite of their importance in fields ranging from biotechnology and life sciences to geophysics and climate change. Using an optical cryo-miscroscope and differential scanning calorimetry, we demonstrate that upon cooling of citric acid and sucrose solutions a fast freezing process results in a continuous ice framework (IF) and two freeze-concentrated solution regions of different concentrations, FCS1 and FCS2. The FCS1 is maximally freeze-concentrated and interweaves with IF. The less concentrated FCS2 envelops the entire IF/FCS1.We find that upon further cooling, the FCS1 transforms to glass, whereas the slow freezing of FCS2 continues until it is terminated by a FCS2-glass transition. We observe the resumed slow freezing of FCS2 upon subsequent warming. The net thermal effect of the resumed freezing and a reverse glass-FCS1 transition produces the Ttr2-transition which before has only been observed upon warming of frozen hydrocarbon solutions and which nature has remained misunderstood for decades. [ABSTRACT FROM AUTHOR]
Details
- Language :
- English
- ISSN :
- 20452322
- Database :
- Academic Search Index
- Journal :
- Scientific Reports
- Publication Type :
- Academic Journal
- Accession number :
- 100061099
- Full Text :
- https://doi.org/10.1038/srep07414