摘要
用电场法测定纯向列液晶和宾主液晶的介电各向异性△_ε的值,探讨了△_ε与液晶分子结构的关系;宾主液晶中染料分子与液晶分子的相互作用对△_ε的影响,以及△_ε与阈值电压V_(th)的关系。实验中还发现:正性液晶分子中含有氰基—CN基团,导致液晶△_ε增高,其值可高达10以上;宾主盒的有序参数高者,一般△_ε也较大;染料分子与液晶分子偶极作用大者,△_ε也增大,而阈值电压则降低。一般说来,染料分子的渗入会升高阈值电压。
A method of measuring the dielectric anisotropy of nemetic liquid crystal and quest-host liquid crystal at an applied electric field was introduced. The relations between Δε and molecular structures, Δε and threshold voltages Ⅴth of liquid crystals, the effect on Δε by the interaction between molecules of liquid crystals and dye molecules in G. H. liquid crystals were discussed. The cyanogen—CN group in the molecules of the positive liquid crystal may cause that Δε values increase to above 10. If the order parameter of G. H. cell is high, Δε becomes high, and if the dipole moment between dye molecules and molecules of liquid crystal is high, Δε becomes high, too. Meanwhile, the increase of Δε value may decrease threshold voltage.
关键词
液晶
电场诱导
介电各向异性
electric induction
guest-host liquid crystals
dielectric anisotropy
anthraquinone dyes
threshold voltage
