Salt Addition Effects on the Phase Behavior of Liquid-Crystalline Cellulose Derivatives and Dynamic Control of their Optical Properties by Electrical Stimulation

许多纤维素聚合物都能在浓缩的流体状态中形成一个“胆固醇”液体-克里斯汀相位。一些集中的解决方案和/或蜂窝衍生物的混合物是彩色的，可以选择性地反射可见光，从胆固醇周期中产生。作为一个典型的例子， （hydroxypropyl） cellulose （HPC）是众所周知的，可以在聚合物集中解决方案中展示这一光学属性。50-70重量%。最大反射率的波长（lambda M）可以与德弗里斯方程的胆固醇音高（P）有关，lambda M =n^^-·P，与液体晶体管系统的平均反射指数n^^-有关。在目前的工作中，我们通过光谱学和核磁共振技术研究了补充中性盐对相位行为和光学特性的影响。Furthermore，我们提出了一个新颖的方法来控制HPC/盐/水液体晶体的选择性光线反射。The The ... More 以下结果值得注意：1。Lambda的价值，因此P，也是，增加了一个被称为添加盐的阳性混沌效应的强度;这种效应变成了阳性，例如，在Cl^-<Br^-<NO_3^-<I^-<SCN^-的顺序中，当将一系列盐与一个常见的盐相比较时，将各种盐添加到HPC/水系统中，也影响了LCST类型的相位分离行为。在转移云点上给予盐的有效性（Tc）无论是降还是降都是非常相似的，因为盐改变了胆固醇的音调。HPC/盐/水液体晶体的选定样本在平行玻璃板之间被分离成一对铂（Pt）板作为间隔和电极的平行玻璃板之间被夹心。然后，一种潜在的电力差异被应用于Pt电极之间。它发现了反射性颜色，即使是相对较弱的电场的作用（3.0 V/cm）的光学密度也是可变的。这是一种可能的结果，即盐-常量连接的电泳迁移，作为胆固醇排序的持久性。Less（低）

Many cellulosic polymers are capable of forming a 'cholesteric' liquid-crystalline phase in a condensed fluid state. Some concentrated solutions and/or melts of cellulose derivatives are colored due to selective reflection of visible light, originating from the cholesteric periodicity. As a typical example, (hydroxypropyl) cellulose (HPC) is known well to exhibit this optical property in aqueous solutions at polymer concentrations of ca. 50-70 wt%. The wavelength (lambdaM) of maximal reflectance can be related to the cholesteric pitch (P) by the de Vries equation, lambdaM=n^^-・P,with an average refractive index n^^- of the liquid-crystalline system. In the present work, we investigated the effects of addition of neutral salts on the phase behavior and optical characteristics of aqueous HPC solutions by spectrophotometry and NMR techniques. Furthermore, we made a novel attempt to control the selective light reflection of the HPC/salt/water liquid crystals by electrical stimulation. The … More following results are worth noting :1. The value of lambdaM and therefore that of P,too, increased with an increase in strength of a so-called chaotropic effect of additive salts ; this effect becomes pronounced, e.g., in order of Cl^-<Br^-<NO_3^-<I^-<SCN^-, when compared in a series of salts with a common cation sort.The addition of various salts into the HPC/water system also affected the LCST-type phase separation behavior. The effectiveness of a given salt in shifting the cloud point (Tc) either down or up was very similar to that of the salt in altering the cholesteric pitch.2. Selected samples of the HPC/salt/water liquid crystals were sandwitched between parallel glass plates separated by a pair of platinum (Pt) plates as a spacer and electrode. Then an electric potential difference was applied between the Pt electrodes. It was found that the reflective coloration and even the optical turbidity of the aqueous cellulosic liquid crystals were changeable by the action of a relatively weak electric field (3.0 V/cm). This is possibly due to electrophoretic migration of the salt-constituent joins as perturbant of the cholesteric ordering. Less