The glass transition and reaction kinetics under nanoconfinement

Date

2010-12

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Abstract

The glass transition temperature (Tg) of the bulk state has been extensively studied, however there is no adequate theory of the glass transition. Furthermore, under nanoconfinement, Tg decreases, increases, or remains the same compared with that of the bulk, with results depending on starting material, confinement medium, sample preparation methods, and measurement technique. An adequate explanation of the diverse results has not been developed yet. Hence, well-designed experimental approaches under nanoconfinement may not only enrich current experimental facts but also may help establish an inclusive understanding of Tg under nanoconfinement. Once Tg under nanoconfinement is elucidated, this solution may be applicable to solve the bulk Tg problem also.
Reactivity under nanoconfinement also changes from the bulk reaction. Unlike Tg, reaction kinetics under nanoconfinement has not been well studied. Recently, the enhance reactivity under nanoconfinement was found and possible reasons were suggested to be incomplete conversion, side reaction, changes in reaction mechanism, reduced activation energy, and/or higher collision efficiency, but prior to the work done here, the origin of the changes was still unclear. A primary goal of this work is to study the Tg behavior under the nanoconfinement geometry of thin films and in nanopores. In addition, a second goal is to study the reaction kinetics under nanopore confinement and to investigate the origin of the enhanced reactivity.

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Keywords

Glass transition, Physical aging, Nanoconfinement, Thin film, Nanopore, Absolute heat capacity, Reactivity under nanoconfinement

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