Time evolution of the thermal properties during dehydration of sol-gel titania emulsions
Nanostructured titania (TiO2) has been extensively studied as a very promising material for applications in sensors, photocatalysis, solar energy conversion and optical coatings. As the properties of titania are determined by its different phases (i.e. rutile and anatase) and these phases depend upon the synthesis method employed, it is important to understand the change in properties that occurs during the synthesis process.
Thermal effusivity has been previously used in the study of the time evolution of dynamical systems in which polymerization and dehydration is involved.
In this work published in AZojomo* by A. Hernández-Ayala, T. López, P. Quintana , J. J. Alvarado-Gil and J. Pacheco from Centro de Investigación y de Estudios Avanzados del Instituto Politécnico Nacional (IPN)-Mérida and Universidad Autónoma Metropolitana-Iztapalapa the evolution of the thermal effusivity as a function of time is monitored using photoacoustic spectroscopy during the process of dehydration in a sol-gel formed titania sample.
During the dehydration process, the thermal effusivity showed a decrease in two successive stages that diminish as a function of time. Each of these stages followed a sigmoidal pattern of behavior. These results indicate that the thermal treatment influenced the dehydration process. The analysis of the dynamics of thermal effusivity allows the analysis of the mode in which water is released from the material. The relationship between the degradation of the organic matrix and phase transitions due to the thermal treatment are discussed.
Source: Eurekalert & othersLast reviewed: By John M. Grohol, Psy.D. on 21 Feb 2009
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