Dielectric behavior of a thermotropic liquid crystal incorporated in a porous glass

We present measurements of the dielectric constant in a composite system where a thermotropic liquid crystal is incorporated in a silica aerogel. In particular we discuss the observed features in the temperature dependence of ε´_L (T), the real part of the dielectric constant measured at low frequency. ε´_L (T) is smaller than the orientational average of the uniaxial anisotropic dielectric constant of the bulk. After rescaling, ε´_L(T) well approximates the temperature dependence of the bulk dielectric behavior. This fact strongly suggests that the silica to liquid crystal interaction is strong and it enables to estimate the total silica surface