Spatially resolved measurements of thermal parameters in colloidal suspensions in liquid crystals

Mercuri, F.; Zammit, U.; Marinelli, M.
November 2004
Applied Physics Letters;11/15/2004, Vol. 85 Issue 20, p4642
Academic Journal
We report on spatially resolved measurements with a spatial resolution of about 0.1 mm of the transition temperature and of the behavior of the heat capacity, thermal conductivity, and thermal diffusivity over the smectic A-nematic and nematic-isotropic phase transitions in an inhomogeneous aerosil dispersed 8CB liquid crystal. The results were obtained by means of a recently implemented photopyroelectric setup which combines the capability for high temperature resolution measurements with the possibility of visual access in the sample. It is shown that the results relative to different local concentration of particles are consistent with the ones obtained previously on homogeneous samples with different average particle concentration. Finally, the analysis of the local thermal conductivity values has led to an approximate estimate of the local particle concentration in the sample.


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