Comparative Studies on Dielectric Properties of Liquids and Solids by Time-Domain Reflectometry

The complex permittivity, ε*=ε'- 𝔦ε", has been measured for six alcohols in the liquid state and two solid polymers by Cole's multiple-reflection-time-domain spectroscopy method. The instrumental frequency range was about 1 MHz to 4 GHz but analyses using Cole's method allow the determination of the static permittivities of the liquids with surprisingly good results. The results also compare favorably with frequency-domain measurements, but require a much shorter time to acquire. The materials studied were methanol, ethanol, butanol, octanol, decanol, dodecanol, poly(vinylidene fluoride), and poly (tetrafluoroethylene). The solid samples still present challenging experimental problems, which are discussed.