J. Phys. IV France 125 (2005) 177-180
Photoacoustic thermal characterization of the dehydration process of Agar-SiO2 emulsionsT. Lopez1, M. Picquart1, G. Aguirre1, Y. Freile2, D.H. Aguilar3, P. Quintana3 and J.J. Alvarado-Gil3
1 Universidad Autonoma Metropolitana-Iztapalapa, A.P. 55-534, 09340 Mexico DF, Mexico
2 Cinvestav del IPN - Unidad Merida, Departamento de Recursos del Mar y, A.P. 73, 97110 Merida, Yucatan, Mexico
3 Cinvestav del IPN - Unidad Merida, Departamento de Fisica Aplicada, A.P. 73, 97110 Merida, Yucatan, Mexico
The evolution of the thermal effusivity as a function of time of aqueous emulsions made by sol-gel synthesis of agar encapsulated in a SiO2 matrix is monitored during dehydration. Measurements of thermal effusivity were performed by the photoacoustic technique, using a conventional cell. Thermal effusivity showed a two stages sigmoidal decrease as a function of time during the dehydration process. Our results indicate that pH has a strong influence on the dehydration process, producing longer characteristic time intervals for pH7.
© EDP Sciences 2005