标题： 基于苯基嘧啶的液晶中的巨大介电常数和超顺电性 显示英文标题

标题： Colossal Dielectric Permittivity and Superparaelectricity in phenyl pyrimidine based liquid crystals

摘要： 一组具有大偶极矩（mu > 10.4-14.8 D）的极性棒状液晶分子，其分子结构基于铁电向列相原型DIO，被设计、合成并进行了研究。 当末尾的氟苯环被苯基嘧啶基团取代时，分子偶极矩从DIO的9.4 D增加到新分子的10.4 D，而当末端的氟基团进一步被氰基取代时，偶极矩增加到14.8 D。 这种取代不仅增强了分子的净偶极矩，还减少了分子内部基团旋转的立体阻碍。 这些化合物的超顺电向列相（N）和层列相A（SmA）表现出巨大的介电常数，既通过介电谱测得，也通过简单的电容分压器电路进行电容测量获得。 电极化强度随电场（E）的变化进行测量。 然而，在向列相和层列相A中未发现P与E之间的滞后现象。 巨大的介电常数在整个流体范围内持续存在。 实验结果使我们得出结论，由于不存在滞后现象和线性P与E关系，这些材料属于超顺电体（SPE）类，而不是铁电体。 合成的有机材料是首次发现超顺电性的流体，并且这些材料在用于储存能量的超级电容器中显示出巨大的应用潜力。 显示英文摘要

摘要： A set of polar rod-shaped liquid crystalline molecules with large dipole moments (mu > 10.4-14.8 D), their molecular structures based on the ferroelectric nematic prototype DIO, are designed, synthesized, and investigated. When the penultimate fluoro-phenyl ring is replaced by phenylpyrimidine moiety, the molecular dipole moment increases from 9.4 D for DIO to 10.4 D for the new molecule and when the terminal fluoro-group is additionally replaced by the nitrile group, the dipole moment rises to 14.8 D. Such a replacement enhances not only the net dipole moment of the molecule, but it also reduces the steric hindrance to rotations of the moieties within the molecule. The superparaelectric nematic (N) and smectic A (SmA) phases of these compounds are found to exhibit colossal dielectric permittivity, obtained both from dielectric spectroscopy, and capacitance measurements using a simple capacitor divider circuit. The electric polarization is measured vs. the field (E). However, no hysteresis in P vs. E is found in the nematic and smectic A phases. The colossal dielectric permittivity persists over the entire fluidic range. The experimental results lead us to conclude that these materials belong to the class of superparaelectrics (SPE) rather than to ferroelectrics due to the absence hysteresis and linear P vs E dependence. The synthesized organic materials are the first fluids for which superparaelectricity is discovered and furthermore these show great potential for the applications in supercapacitors used in storing energy.