Linked Life Data

19708750

Source:http://linkedlifedata.com/resource/pubmed/id/19708750

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
7
pubmed:dateCreated
2009-8-27
pubmed:abstractText
The liquid dynamics of 5-methyl-2-[(2-nitrophenyl)amino]-3-thiophenecarbonitrile, named ROY for its red, orange, and yellow crystal polymorphs, was characterized by dielectric spectroscopy and differential scanning calorimetry. Four of these polymorphs show fast "diffusionless" crystal growth at low temperatures while three others do not. ROY was found to be a typical fragile organic liquid. Its alpha relaxation process has time-temperature superposition symmetry across the viscous range (tau(alpha)=100 s-100 ns) with the width of the relaxation peak characterized by a constant beta(KWW) of 0.73. No secondary relaxation peak was observed, even with glasses made by fast quenching. For the polymorphs not showing fast crystal growth in the glassy state, the growth rate has a power-law relation with tau(alpha), u proportional to tau(alpha)(-xi), where xi approximately = 0.7. For the polymorphs showing fast crystal growth in the glassy state, the growth is so fast near and below the glass transition temperature T(g) that thousands of molecular layers can be added to the crystalline phase during one structural relaxation time of the liquid. In the glassy state, this mode of growth slows slightly over time. This slowdown is not readily explained by the effect of physical aging on the thermodynamic driving force of crystallization, the glass vapor pressure, or the rate of structural relaxation. This study demonstrates that from the same liquid or glass, the growth of some polymorphs is accurately described as being limited by the rate of structural relaxation or bulk diffusion, whereas the growth of other polymorphs is too fast to be under such control.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Aug
pubmed:issn
1089-7690
pubmed:author
pubmed:issnType
Electronic
pubmed:day
21
pubmed:volume
131
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
074506
pubmed:meshHeading
pubmed:year
2009
pubmed:articleTitle
Diffusion-controlled and "diffusionless" crystal growth near the glass transition temperature: relation between liquid dynamics and growth kinetics of seven ROY polymorphs.
pubmed:affiliation
Department of Chemistry, University of Wisconsin-Madison, Madison, Wisconsin 53706, USA.
pubmed:publicationType
Journal Article, Research Support, U.S. Gov't, Non-P.H.S., Research Support, Non-U.S. Gov't