Rai Pradeep K, Denn Morton M, Khusid Boris
Benjamin Levich Institute for Physico-Chemical Hydrodynamics and Department of Chemical Engineering, City College of New York/CUNY, New York, New York 10031, USA.
Langmuir. 2006 Mar 14;22(6):2528-33. doi: 10.1021/la053489o.
We describe dielectric spectroscopy measurements on dispersions of two thermotropic liquid crystals (5CB and 8CB) in a poly(dimethylsiloxane) matrix. 5CB exhibits nematic and isotropic phases, while 8CB exhibits smectic, nematic, and isotropic phases. The spectra of the dispersions exhibit a temperature-dependent dielectric relaxation in the interval from 100 to 1000 Hz, with relaxation times that depend strongly on whether the dispersed phase is isotropic, nematic, or smectic. The dielectric relaxation times also depend on the viscosity of the matrix fluid. These results suggest a coupling between the electric field and the mechanics of the interface that affects the spectrum of the dispersed phase and shifts the Maxwell-Wagner interfacial polarization peak.
我们描述了在聚二甲基硅氧烷基质中两种热致液晶（5CB和8CB）分散体的介电谱测量。5CB呈现向列相和各向同性相，而8CB呈现近晶相、向列相和各向同性相。分散体的光谱在100至1000 Hz的区间内呈现出与温度相关的介电弛豫，其弛豫时间强烈依赖于分散相是各向同性、向列相还是近晶相。介电弛豫时间还取决于基质流体的粘度。这些结果表明电场与界面力学之间存在耦合，这会影响分散相的光谱并使麦克斯韦-瓦格纳界面极化峰发生偏移。
