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dc.contributor.authorMacLaren, Douglas C.en_US
dc.date.accessioned2014-10-21T12:38:47Z
dc.date.available2014-10-21T12:38:47Z
dc.date.issued2003en_US
dc.identifier.otherAAINQ83714en_US
dc.identifier.urihttp://hdl.handle.net/10222/55939
dc.descriptionThree-component organic thermochromic systems have potential applications in reversible, rewritable thermal printing. In principle, such mixtures could maintain a coloured or non-coloured state at ambient temperature depending on their thermal treatment. These systems generally consist of a functional dye (1--3 mol%), a weakly acidic colour developer (5--25 mol%), and a high-melting organic solvent (75--90 mol%). Colour development occurs at the fusion temperature of the mixture, which triggers the interaction of the dye and developer. Slow cooling of the melt results in an equilibrium state with low colour density, whereas rapid cooling of the melt results in a metastable state with high colour density. The metastable state can be decoloured by heating to an intermediate decolourisation temperature at which the coloured state becomes unstable.en_US
dc.descriptionBarriers to the widespread use of reversible, rewritable thermochromic materials include problems with colour contrast, colour stability, and decolourisation rates. Development is hindered by a lack of detailed knowledge of the interactions between components in these systems.en_US
dc.descriptionIn this study the developer-dye and developer-solvent interactions were examined for an archetypal dye/developer/solvent thermochromic system. Vibrational spectroscopy, NMR, and thermal analysis were used to examine compounds formed in developer/dye and developer/solvent binary mixtures. Rewritable thermochromic properties such as metastable colour density, equilibrium colour density, and decolourisation rates were examined and discussed in terms of the thermodynamics of the developer/dye and developer/solvent interactions.en_US
dc.descriptionObserved thermochromic properties are shown to be strongly correlated to a competition between the dye and the solvent for interaction with the developer. Increasing the attractive interaction between the solvent and developer results in enhanced rewritable thermochromic properties.en_US
dc.descriptionThesis (Ph.D.)--Dalhousie University (Canada), 2003.en_US
dc.languageengen_US
dc.publisherDalhousie Universityen_US
dc.publisheren_US
dc.subjectEngineering, Materials Science.en_US
dc.titleInvestigations of reversible thermochromic mixtures.en_US
dc.typetexten_US
dc.contributor.degreePh.D.en_US
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