The effect of a lateral alkyloxy chain on the ferroelectric nematic phase.
The effect of a lateral alkyloxy chain on the ferroelectric nematic phase.
复制标题
作者：
报道了两个系列低摩尔质量液晶的合成和表征，即4-[(4-硝基苯氧基)羰基]苯基2-烷氧基-4-甲氧基苯甲酸酯(系列5-m)和4-[(3-氟-4-硝基苯氧基)羰基]苯基2-烷氧基-4-甲氧基苯甲酸酯(系列6-m)，以探索侧烷氧基链对最近发现的液晶的形成和稳定性的影响。铁电向列相。在这两个系列中，m（侧链中的碳原子数）从 1 到 9 不等。这两个系列的不同之处在于 6-m 系列中添加了氟取代基。 5-1 是广泛研究的铁电线虫 RM734。 5-m 系列的所有成员都表现出传统向列相 (N) 和铁电向列相 (NF)，而 6-m 系列的所有成员都表现出直接 NF-I 转变，但 6-1 除外，它也表现出 N 相。用氟原子取代氢原子会降低向列相-各向同性转变温度 TNI，而铁电向列相-向列相或各向同性转变温度 TNFN/I 会增加。这可以解释为与较大氟原子相关的结构各向异性降低，而 NF 相稳定性的增加反映了极性和极化率的变化。两个系列中 TNI 和 TNFN/I 对 m 的依赖性相似，并且它们最初随着 m 的增加而减小，但随着 m 的进一步增加而收敛到极限值。这表明侧烷氧基链可能采用沿着介晶单元的主轴的构象。讨论了两个系列的铁电向列相的性质，以了解横向体积对铁电向列相的影响。
The synthesis and characterisation of two series of low molar mass liquid crystals, the 4-[(4-nitrophenoxy)carbonyl]phenyl 2-alkoxy-4-methoxybenzoates (series 5-m) and the 4-[(3-fluoro-4-nitrophenoxy)carbonyl]phenyl 2-alkoxy-4-methoxybenzoates (series 6-m) are reported in order to explore the effects of a lateral alkyloxy chain on the formation and stability of the recently discovered ferroelectric nematic phase. In both series m, the number of carbon atoms in the lateral chain, is varied from one to nine. The two series differ by the addition of a fluorine substituent in the 6-m series. 5-1 is the extensively studied ferroelectric nematogen RM734. All the members of the 5-m series exhibited both a conventional nematic, N, and ferroelectric nematic, NF, phase, whereas all the members of the 6-m series exhibit a direct NF–I transition with the exception of 6-1 that also exhibits a N phase. The replacement of a hydrogen atom by a fluorine atom reduces the nematic–isotropic transition temperature, TNI, whereas the ferroelectric nematic–nematic, or isotropic, transition temperature, TNFN/I, increases. This is interpreted in terms of the reduced structural anisotropy associated with the larger fluorine atom whereas the increase in the stability of the NF phase reflects changes in polarity and polarizability. The dependence of TNI and TNFN/I on m in both series is similar, and these initially decrease on increasing m but converge to limiting values on further increasing m. This suggests that the lateral alkyloxy chain may adopt conformations in which it lies along the major axis of the mesogenic unit. Properties of two series of ferronematogens are discussed to understand the influence of lateral bulk on the ferroelectric nematic phase.
登录
查看更多内容
影响因子：
13.6
作者：
Li J;Nishikawa H;Kougo J;Zhou J;Dai S;Tang W;Zhao X;Hisai Y;Huang M;Aya S
通讯作者：
Aya S
影响因子：
4.6
作者：
Rudquist P
通讯作者：
Rudquist P
影响因子：
29.4
作者：
Nishikawa, Hiroya;Shiroshita, Kazuya;Kikuchi, Hirotsugu
通讯作者：
Kikuchi, Hirotsugu
影响因子：
16.6
作者：
Mandle RJ;Sebastián N;Martinez-Perdiguero J;Mertelj A
通讯作者：
Mertelj A
影响因子：
2.2
作者：
GOVIND, AS;MADHUSUDANA, NV
通讯作者：
MADHUSUDANA, NV