我们感谢 Takanishi 教授在我们实验中的帮助。我们还感谢 DIC 公司提供了这里所研究的化合物。这项工作得到了 jsp 研究员 (16J02711)、jsp KAKENHI 赠款号17H01143 的资助, 以及领导研究生院 "交互式材料军校学生计划" 的资助。

1. 液晶细胞的制备及细胞间隙的测定
<ol><li>
液晶电池的制备
	<ol>
<li>将镀铟/锡氧化物 (ITO) 的玻璃基体切割成所需尺寸 (典型尺寸:10 x 10 x 1.1 毫米,图 2A)。要切割基板, 请用玻璃切割机在他们的脸上划上一条线, 手动切断多余的玻璃。</li>
		<li>用35赫的超声波浴中的洗涤剂清洗切割玻璃基板30分钟. 在超声波浴中用去离子水冲洗10分钟. 更换去离子水并冲洗衬底5次以去除污染物 (图 2B)。用空气除尘器把剩余的水吹掉, 小心不要碰到最宽的底面。</li>
		<li>滴灌聚酰亚胺溶液 (对齐层刨床在材料表) 上的 ITO 涂层一侧的洗涤基质, 并纺大衣的解决方案在 5000 rpm 三十年代 (图 2C)。将基材烘烤200摄氏度, 1 小时, 去除溶剂, 固化聚酰亚胺薄膜。</li>
		<li>把基板放在一个XZ的舞台上, 使基体表面的 ITO 和聚酰亚胺涂层面朝上。将衬底放在用天鹅绒布覆盖的滚筒下, 用空气吸痰固定衬底 (图 2D)。通过调整舞台的高度, 对基板施加均匀和软压力。 注: 在这里, XZ 阶段是由大阪大学的一个机器商店。</li>
		<li>旋转滚筒, 沿水平方向来回移动舞台5次, 用天鹅绒布擦衬底。在 10-50 毫升的玻璃容器中, 将所摩擦的基体蘸上异丙醇, 以去除污染物, 并在80摄氏度内将其干燥几分钟。</li>
		<li>将两个衬底与12微米厚度平板树脂薄膜粘合在一起。注意, 粘接点只放在基体的边缘, 胶合基体的内侧涂上 ITO 和聚酰亚胺。确保相反的基板被摩擦反并联和轻微转移 (约2毫米), 以提供足够的空间, 在两个基板上的电气端子 (图 2E)。</li>
		<li>使用银导电膏将导电导线粘附在上述空间的端子上 (图 2F)。用导电导线在150摄氏度烘烤基板, 1 小时, 以去除银导电膏中的溶剂。</li>
	</ol>
</li>
	<li>
细胞间隙的测定19<ol>
<li>照射在1.1.7 中制备的空白细胞, 白色光传播正常到其最宽的面。用光学光谱仪测量透射光谱, 观察伪正弦振荡 (图 3), 这是由于法-Pérot 效应20而出现的。</li>
		<li>使用关系估计细胞间隙d = λ1λ2/2 (λ2-λ1), 波长λ1和λ 2表示传输谱中的一对相邻峰值波长。</li>
	</ol>
</li>
</ol>2. 液晶混合物的制备及在细胞中的引入
<ol><li>混合两个化合物, 5-辛-2-(4-octyloxyphenyl) 嘧啶 (复合1:图 4A) 和 (S)-5-癸基-2-[4 (2-fluorodecyloxy) 苯基] 嘧啶 (复合2:图 4B) 与质量比率3:1 在玻璃瓶。共制备100毫克溶液 (75 毫克化合物1和25毫克化合物2)。</li>
	<li>把准备好的空白细胞从台阶1.1.7 在一个热的阶段, 保持温度在80°c, 温度在其中混合物从2.1 在各向同性的液体阶段 (图 5)。使用刮刀和毛细管动作将步骤2.1 中的混合物引入细胞中。保持80摄氏度的细胞温度为30分钟, 然后冷却到室温的速率约5°c/分钟。</li>
</ol>3. 样品表征
<ol><li>放置一个细胞填充与混合物从步骤2.2 在一个热点阶段之间的两个交叉偏振片, 并照射它与光。使用显微镜观察混合物的质地, 温度从室温变到80°c, 速度为5摄氏度/分钟, 并通过一个短通滤波器, 调整范围为 ~ 600 nm, 以提高能见度, 如有必要), 并确定液晶相偏振显微照片21 (图 6)。</li>
	<li>从观测到的纹理确定相变序列和过渡温度 (图 5)。对于 SmC * 阶段, 估计螺旋间距为双条纹宽度。</li>
	<li>用差分热分析法确定2.1 型混合料的一阶相变温度 (DTA; 参见材料表和制造商说明), 在一阶阶段提供峰值 (或倾角) 异常转换 (图 7)。</li>
</ol>4. 介质和磁电测量
<ol><li>准备一个商用超导磁体 (见材料表), 配备温度控制器 (2-400 K) 和磁场 (最多9吨)。</li>
	<li>为超导磁体准备一个自制的插入件, 它由三主要部件组成: 样品空间, 一杆包括四同轴电缆和一个连接器端子 (图 8A)。</li>
	<li>将在2.2 中准备好的单元格粘附在插入的样本空间上 (图 8B)。通过焊接将电池的两条导电导线连接到样品空间的端子 (高和低)。确保单元格方向, 以便在与单元格的基板平行的方向上应用磁场。将温度计放在细胞最宽的平面上, 以便准确测量样品温度, 并将插入物引入超导磁体。</li>
	<li>将接头终端连接到LCR表 (参见材料表), 并使用同轴电缆。用LCR计 (参见制造商的说明和我们以前的工作16), 以四的终端方法测量电介质常数作为温度和磁场的函数。</li>
	<li>用同轴电缆将接头端子连接到静电计 (见材料表)。在扫磁场和温度恒定的情况下, 测量与静电计的位移电流的磁场和温度依赖性 (扫磁场的 1.0 T/分钟, 扫入温度的 5 K/分钟; 请参阅制造商的说明和我们以前的工作16)。通过将位移电流作为时间函数来获得电极化。</li>
</ol>

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作者没有什么可透露的。

实验结果表明, 本文所描述的方法成功地证明了液晶中的偶联。在固定的 smectic 层结构中, 观察到的我和磁介电效应可以与分子取向的取向转移有关。然而, 层状结构中的层法线方向n0也可以通过磁各向异性施加磁场来改变。这是因为分子倾向于通过它们的磁性各向异性来进行n和磁场的平行排列。n0和磁场的平行布置也比 SmC...

磁电 (i.) 效应的研究, 电磁 (电) 磁场诱导极化 (磁化), 一直致力于新型的应用, 如传感器和存储技术。最近对我的研究 multiferroics1,2,3,4, 我研究领域的目标系统扩展到各种类型的固态材料, 包括无机, 有机, 和金属-有机框架, 利用自旋晶格联轴器巧妙5,6,7,8,9。然而, 室温操作, 必须完成, 以实际利用我的材料与他们的我联轴器, 仍然是一个具有挑战性的问题, 并报告了非常有限的单相材料的室温magnetoelectrics 至今10。
液体水晶, 拥有一个取向顺序, 有时以部份位置一, 也被审查了关于我材料在最近岁月11,12,13,14,15. 液晶作为我材料的优点之一是它们的工作温度, 因为液态晶体相通常在室温下稳定。我的一个例子液晶报告到目前为止是一个复合体磁性纳米血小板与垂直磁性各向异性和液晶显示的向列相, 称为最简单的液晶相, 只有一维取向命令15。通过对耦合血小板的电场操作和分子方向的分析, 表明了电场对磁化的影响。
最近, 提出了另一个独特的战略, 以建立在液态晶体的我的作用,16。这一策略的重点是创建一个手性 smectic C (SmC *) 阶段与一维位置顺序, 导致一个扩散层结构称为 smectic 层。SmC * 相的一个特征是分子取向向量n与局部电偶极矩p耦合。这种相关性是由杆状成分分子的倾斜方向与 smectic 层法线n0的结合, 以及在分子中的手性诱导镜 (和反转) 对称断裂提供的。从对称性的角度, 前者将D∞h (所谓的 SmA 相、图 1A) 的对称性改变为C2h (即所谓 SmC 相、图 1B) 和后者打破c2h的镜像对称性, 使对称度降低为c2 (SmC * 阶段, 参见图 1C中的每一层)。在每个 SmC * 层中, 允许沿C2轴存在有限极化, 这对n0和n都是正常的。n和p之间的强耦合是液晶中铁电性的必要条件。在 SmC * 阶段, n以螺旋方式通过图层 (图 1C) 对齐, 因此没有宏观极化。这种液晶中的铁电性是通过使用强表面效应来实现的, 它稳定了n被称为表面稳定铁电液晶 (SSFLC) 状态的均匀取向状态 (图 1D)。应该指出的是, 铁电极化反转总是伴随着双稳态方向状态的开关, 通过n和p17之间的耦合。作为逆效应, SmC * 相的分子取向的变化预期会引起电极化的变化。通过磁性元素和/或在液晶分子中的芳香环上的旋转引起的磁各向异性, 以及由于分子相互作用较弱而在液态晶体状态下的n的弹性, n是也可由磁场调谐。因此, SmC * 相可以转化为磁场诱导的均匀定向状态, 类似于 SSFLC 状态。因此, 当宏观极化的发展是由n和p的均匀对准, 在所有层中产生时, 直接的我效应, 通过磁场诱导电极化。
我们介绍的程序, 以准备液晶细胞的调查我的联结和方法, 以检测我的效果。本文详细地介绍了一种制备液晶细胞的方法, 前18。在这里, 我们修改了这个方法的介电和我的测量。在这里详细介绍了该方法, 我们检测到磁调谐电极化, 即直接我的作用, 在液晶显示 SmC * 阶段在室温下。

<table><tbody><tr><td>&lt;strong&gt;Material&lt;/strong&gt;</td><td></td><td></td><td></td></tr><tr><td>Compound 1: Figure 4(A)</td><td>DIC Co., Ltd.</td><td>&amp;ndash;N/A</td><td>PYP-8O8</td></tr><tr><td>Compound 2: Figure 4(B)</td><td>DIC Co., Ltd.</td><td>N/A</td><td>PYP-10O10F</td></tr><tr><td>ITO-coated glass substrates</td><td>Sigma-Aldrich Inc.</td><td>703192-10PK</td><td></td></tr><tr><td>Detergent</td><td>Wako Pure Chemical Industries, Ltd.</td><td>031-10401</td><td></td></tr><tr><td>Alignment layer planer</td><td>JSR Co., Ltd.</td><td>AL1254</td><td></td></tr><tr><td>Spacer</td><td>Teijin Film Solutions Co., Ltd.</td><td>Q51-12</td><td></td></tr><tr><td>Glue</td><td>Huntsman Inc.</td><td>ARALDITE RT30</td><td>For gluing two substrates</td></tr><tr><td>Glue</td><td>M&amp;amp;I Materials ltd.</td><td>Apiezon H Grease</td><td>For gluing a cell and homemade insert</td></tr><tr><td>Silver paste</td><td>Fujikura Kasei Co., Ltd.</td><td>D-753</td><td></td></tr><tr><td>&lt;strong&gt;Equipment&lt;/strong&gt;</td><td></td><td></td><td></td></tr><tr><td>Ultrasonic cleaner</td><td>AS ONE Corp.</td><td>AS52GTU</td><td></td></tr><tr><td>Spin coater</td><td>Mikasa Co. Ltd.</td><td>1H-D7</td><td></td></tr><tr><td>Polarized optical microscope</td><td>Nikon Co., Ltd.</td><td>ECLIPSE LV100N POL</td><td></td></tr><tr><td>Short-pass filter</td><td>Thorlabs Inc.</td><td>FB600-40</td><td></td></tr><tr><td>Optical spectrometer</td><td>Ocean Optics Inc.</td><td>USB2000+UV-VIS</td><td></td></tr><tr><td>Differential thermal analyzer</td><td>Rigaku Co., Ltd.</td><td>Thermo plus EVO2</td><td></td></tr><tr><td>Superconducting magnet</td><td>Quantum Design Inc.</td><td>PPMS</td><td></td></tr><tr><td>LCR meter</td><td>Keysight Technologies Ltd.</td><td>E4980A</td><td></td></tr><tr><td>Electrometer</td><td>Keithley Instruments Inc.</td><td>6517A</td><td></td></tr></tbody></table>

measuring magnetically-tuned ferroelectric polarization in liquid crystals

材料显示, 磁性和 (铁) 电之间的耦合现象,即电磁效应, 引起了很大的关注, 因为他们的潜在应用, 未来的设备技术, 如传感器和存储。然而, 通常使用含有磁性金属离子 (或自由基) 材料的常规方法有一个主要问题: 只有少数材料被发现在室温下显示耦合现象。最近, 我们提出了一种实现室温 magnetoelectrics 的新方法。与传统的方法相反, 我们的替代方案侧重于一种完全不同的材料, 即 "液晶", 不含磁性金属离子。在这种液晶中, 磁场可以通过分子的磁性各向异性来控制组成分子的取向态和相应的电极化;这是一个空前的磁电效应机制。在这一背景下, 本文提供了一种测量磁场诱发的铁电性质的协议, 即在液晶中的直接磁磁场效应。在此方法中, 我们成功地检测到在室温下液晶手性 smectic C 相的磁调谐电极化。结合构成分子的灵活性, 直接影响磁电反应, 引入的方法将使液晶细胞获得更多的功能, 室温 magnetoelectrics 和相关光学材料。

只有当观察到液态晶体样品中的 i 效应时, 该协议才被认为是成功的。在这里, 我们测量了直接的我的作用, 在一个液晶样品所编写的上述程序。对于测量, 在平面磁场中应用的角度倾斜由约45°从摩擦方向 (正常到 smectic 层), 因为最大的磁场诱导极化检测在这个配置16。
图 9A显示了电极化?...

Watch this Scientific Journal Video about Measuring Magnetically-Tuned Ferroelectric Polarization in Liquid Crystals at JoVE.com

Measuring Magnetically-Tuned Ferroelectric Polarization in Liquid Crystals

在本报告中, 我们提出了一种检验直接磁电效应的协议,即在液晶中应用磁场来诱导铁磁极化。该协议提供了一个独特的方法, 支持的柔软的液晶, 以实现室温 magnetoelectrics。

液晶中磁调谐铁电极化的测量

Materials showing coupling phenomena between magnetism and (ferro)electricity, i.e., magnetoelectric effects, have attracted a great deal of attention due ...

measuring-magnetically-tuned-ferroelectric-polarization-liquid

Universidad de Cartagena UDEC

Research

JoVE Journal

Engineering

8.7K 次观看.  Osaka University. 在本报告中, 我们提出了一种检验直接磁电效应的协议,即在液晶中应用磁场来诱导铁磁极化。该协议提供了一个独特的方法, 支持的柔软的液晶, 以实现室温 magnetoelectrics。

视频: Measuring Magnetically-Tuned Ferroelectric Polarization in Liquid Crystals

Chemical Vapor Deposition of an Organic Magnet, Vanadium Tetracyanoethylene

Recent progress in the field of organic materials has yielded devices such as organic light emitting diodes (OLEDs) which have advantages not found in traditional materials, including low cost and mechanical flexibility. In a similar vein, it would be advantageous to expand the use of organics into high frequency electronics and spin-based electronics. This work presents a synthetic process for the growth of thin films of the room temperature organic ferrimagnet, vanadium tetracyanoethylene (V[TCNE]x, x~2) by low temperature chemical vapor deposition (CVD). The thin film is grown at &#60;60 &#176;C, and can accommodate a wide variety of substrates including, but not limited to, silicon, glass, Teflon and flexible substrates. The conformal deposition is conducive to pre-patterned and three-dimensional structures as well. Additionally this technique can yield films with thicknesses ranging from 30 nm to several microns. Recent progress in optimization of film growth creates a film whose qualities, such as higher Curie temperature (600 K), improved magnetic homogeneity, and narrow ferromagnetic resonance line-width (1.5 G) show promise for a variety of applications in spintronics and microwave electronics.

We present the synthesis of the organic-based ferrimagnet vanadium tetracyanoethylene (V[TCNE]x, x~2) via low temperature chemical vapor deposition (CVD). This optimized recipe yields an increase in Curie temperature from 400 K to over 600 K and a dramatic improvement in magnetic resonance properties.

化学气相沉积的有机磁体，钒四氰

Recent progress in the field of organic materials has yielded devices such as organic light emitting diodes (OLEDs) which have advantages not found in ...

科研

化学

Phase Diagram Characterization Using Magnetic Beads as Liquid Carriers

Magnetic beads with ~1.9 &#181;m average diameter were used to transport microliter volumes of liquids between contiguous liquid segments with a tube for the purpose of investigating phase change of those liquid segments. The magnetic beads were externally controlled using a magnet, allowing for the beads to bridge the air valve between the adjacent liquid segments. A hydrophobic coating was applied to the inner surface of the tube to enhance the separation between two liquid segments. The applied magnetic field formed an aggregate cluster of magnetic beads, capturing a certain liquid amount within the cluster that is referred to as carry-over volume. A fluorescent dye was added to one liquid segment, followed by a series of liquid transfers, which then changed the fluorescence intensity in the neighboring liquid segment. Based on the numerical analysis of the measured fluorescence intensity change, the carry-over volume per mass of magnetic beads has been found to be ~2 to 3 &#181;l/mg. This small amount of liquid allowed for the use of comparatively small liquid segments of a couple hundred microliters, enhancing the feasibility of the device for a lab-in-tube approach. This technique of applying small compositional variation in a liquid volume was applied to analyzing the binary phase diagram between water and the surfactant C12E5 (pentaethylene glycol monododecyl ether), leading to quicker analysis with smaller sample volumes than conventional methods.

Here, we present a protocol to investigate multi-component phase diagrams using externally controlled magnetic beads as liquid carriers in a lab-in-tube approach. This approach can aid in applications that seek to gather further information on phase change in complex liquid systems.

相图表征使用磁珠用作液体载体

Magnetic beads with ~1.9 &#181;m average diameter were used to transport microliter volumes of liquids between contiguous liquid segments with a tube for ...

工程学

From Molecules to Materials: Engineering New Ionic Liquid Crystals Through Halogen Bonding

Herein, we demonstrate that a bottom-up approach, based on halogen bonding (XB), can be successfully applied for the design of a new type of ionic liquid crystals (ILCs). Taking advantages of the high specificity of XB for haloperfluorocarbons and the ability of anions to act as XB-acceptors, we obtained supramolecular complexes based on 1-alkyl-3-methylimidazolium iodides and iodoperfluorocarbons, overcoming the well-known immiscibility between hydrocarbons (HCs) and perfluorocarbons (PFCs). The high directionality of the XB combined with the fluorophobic effect, allowed us to obtain enantiotropic liquid crystals where a rigid, non-aromatic, XB supramolecular anion acts as mesogenic core.
X-ray structure analysis of the complex between 1-ethyl-3-methylimidazolium iodide and iodoperfluorooctane showed the presence of a layered structure, which is a manifestation of the well-known tendency to segregation of perfluoroalkyl chains. This is consistent with the observation of smectic mesophases. Moreover, all the reported complexes melt below 100 &#176;C, and most are mesomorphic even at room temperature, despite that the starting materials were non-mesomorphic in nature.
The supramolecular strategy reported here provides new design principles for mesogen design allowing a totally new class of functional materials.

A protocol for the synthesis of a new type of mesogens, based on the halogen-bonded supramolecular anion [CnF2n+1-I&#183;&#183;&#183;I&#183;&#183;&#183;I-CnF2n+1]&#8722;, is reported.

从分子到材料: 通过卤素键合工程新的离子液体晶体

Herein, we demonstrate that a bottom-up approach, based on halogen bonding (XB), can be successfully applied for the design of a new type of ionic liquid ...

Orientational Transition in a Liquid Crystal Triggered by the Thermodynamic Growth of Interfacial Wetting Sheets

In liquid crystal (LC) physical chemistry, molecules near the surface play a great role in controlling bulk orientation. Thus far, mainly to achieve desired molecular orientation states in LC displays, the "static" surface property of LCs, so-called surface anchoring, has been intensively studied. As a rule of thumb, once the initial orientation of LCs is "locked" by specific surface treatments, such as rubbing or treatment with a specific alignment layer, it hardly changes with temperature. Here, we present a system exhibiting an orientational transition upon temperature variation, which conflicts with the consensus. Right on the transition, the bulk LC molecules experience the orientational rotation, with 90&#176; between the planar (P) orientation at high temperatures and the vertical (V) orientation at low temperatures in the first-order transitional manner. We have tracked thermodynamic surface anchoring behavior by means of polarizing optical microscopy (POM), dielectric spectroscopy (DS), high-resolution differential scanning calorimetry (HR-DSC), and grazing incidence X-ray diffraction (GI-XRD) and reached a plausible physical explanation: that the transition is triggered by a growth of surface wetting sheets, which impose the V orientation locally against the P orientation in the bulk. This landscape would provide a general link explaining how the equilibrium bulk orientation is affected by surface-localized orientation in many LC systems. In our characterization, POM and DS are advantageous by offering information on the spatial distribution of the orientation of LC molecules. HR-DSC gives information about the precise thermodynamic information on transitions, which cannot be addressed by conventional DSC instruments due to limited resolution. GI-XRD provides information on surface-specific molecular orientation and short-range orderings. The goal of this paper is to present a protocol for preparing a sample that exhibits the transition and to demonstrate how the thermodynamic structural variation, both in the bulk and on surfaces, can be analyzed through the abovementioned methods.

Here, we present a protocol to trigger an orientational transition of a liquid crystal in response to temperature. Methodologies are described for preparing a sample in order to observe the transition and the detailed transitional evolution.

由界面润湿片的热力学生长触发的液晶中的定向转变

In liquid crystal (LC) physical chemistry, molecules near the surface play a great role in controlling bulk orientation. Thus far, mainly to achieve ...

Fabrication Procedures and Birefringence Measurements for Designing Magnetically Responsive Lanthanide Ion Chelating Phospholipid Assemblies

Bicelles are tunable disk-like polymolecular assemblies formed from a large variety of lipid mixtures. Applications range from membrane protein structural studies by nuclear magnetic resonance (NMR) to nanotechnological developments including the formation of optically active and magnetically switchable gels. Such technologies require high control of the assembly size, magnetic response and thermal resistance. Mixtures of 1,2-dimyristoyl-sn-glycero-3-phosphocholine (DMPC) and its lanthanide ion (Ln3+) chelating phospholipid conjugate, 1,2-dimyristoyl-sn-glycero-3-phospho-ethanolamine-diethylene triaminepentaacetate (DMPE-DTPA), assemble into highly magnetically responsive assemblies such as DMPC/DMPE-DTPA/Ln3+ (molar ratio 4:1:1) bicelles. Introduction of cholesterol (Chol-OH) and steroid derivatives in the bilayer results in another set of assemblies offering unique physico-chemical properties. For a given lipid composition, the magnetic alignability is proportional to the bicelle size. The complexation of Ln3+ results in unprecedented magnetic responses in terms of both magnitude and alignment direction. The thermo-reversible collapse of the disk-like structures into vesicles upon heating allows tailoring of the assemblies&#39; dimensions by extrusion through membrane filters with defined pore sizes. The magnetically alignable bicelles are regenerated by cooling to 5 &#176;C, resulting in assembly dimensions defined by the vesicle precursors. Herein, this fabrication procedure is explained and the magnetic alignability of the assemblies is quantified by birefringence measurements under a 5.5 T magnetic field. The birefringence signal, originating from the phospholipid bilayer, further enables monitoring of polymolecular changes occurring in the bilayer. This simple technique is complementary to NMR experiments that are commonly employed to characterize bicelles.

Fabrication procedures for highly magnetically responsive lanthanide ion chelating polymolecular assemblies are presented. The magnetic response is dictated by the assembly size, which is tailored by extrusion through nanopore membranes. The assemblies&#39; magnetic alignability and temperature-induced structural changes are monitored by birefringence measurements, a complimentary technique to nuclear magnetic resonance and small angle neutron scattering.

设计磁响应稀土离子螯合磷脂组件的制备方法及双折射测量

Bicelles are tunable disk-like polymolecular assemblies formed from a large variety of lipid mixtures. Applications range from membrane protein structural ...

Novel Techniques for Observing Structural Dynamics of Photoresponsive Liquid Crystals

We discuss in this article the experimental measurements of the molecules in liquid crystal (LC) phase using the time-resolved infrared (IR) vibrational spectroscopy and time-resolved electron diffraction. Liquid crystal phase is an important state of matter that exists between the solid and liquid phases and it is common in natural systems as well as in organic electronics. Liquid crystals are orientationally ordered but loosely packed, and therefore, the internal conformations and alignments of the molecular components of LCs can be modified by external stimuli. Although advanced time-resolved diffraction techniques have revealed picosecond-scale molecular dynamics of single crystals and polycrystals, direct observations of packing structures and ultrafast dynamics of soft materials have been hampered by blurry diffraction patterns. Here, we report time-resolved IR vibrational spectroscopy and electron diffractometry to acquire ultrafast snapshots of a columnar LC material bearing a photoactive core moiety. Differential-detection analyses of the combination of time-resolved IR vibrational spectroscopy and electron diffraction are powerful tools for characterizing structures and photoinduced dynamics of soft materials.

Here, we present the protocols of differential-detection analyses of time-resolved infrared vibrational spectroscopy and electron diffraction which enable observations of the deformations of local structures around photoexcited molecules in a columnar liquid crystal, giving an atomic perspective on the relationship between the structure and the dynamics of this photoactive material.

观测 Photoresponsive 液晶结构动力学的新方法

We discuss in this article the experimental measurements of the molecules in liquid crystal (LC) phase using the time-resolved infrared (IR) vibrational ...

A Fabrication and Measurement Method for a Flexible Ferroelectric Element Based on Van Der Waals Heteroepitaxy

Flexible non-volatile memories have received much attention as they are applicable for portable smart electronic device in the future, relying on high-density data storage and low-power consumption capabilities. However, the high-quality oxide based nonvolatile memory on flexible substrates is often constrained by the material characteristics and the inevitable high-temperature fabrication process. In this paper, a protocol is proposed to directly grow an epitaxial yet flexible lead zirconium titanate memory element on muscovite mica. The versatile deposition technique and measurement method enable the fabrication of flexible yet single-crystalline non-volatile memory elements necessary for the next generation of smart devices.

In this paper, we present a protocol to directly grow an epitaxial yet flexible lead zirconium titanate memory element on muscovite mica.

基于范德华 Heteroepitaxy 的柔性铁电元件制备及测量方法

Flexible non-volatile memories have received much attention as they are applicable for portable smart electronic device in the future, relying on ...

An Electrochemical Cholesteric Liquid Crystalline Device for Quick and Low-Voltage Color Modulation

We demonstrate a method for fabricating a prototype reflective display device that contains cholesteric liquid crystal (LC) as an active component. The cholesteric LC is composed of a nematic LC 4&#39;-pentyloxy-4-cyanobiphenyl (5OCB), redox-responsive chiral dopant (FcD), and a supporting electrolyte 1-ethyl-3-methylimidazolium trifluoromethanesulfonate (EMIm-OTf). The most important component is FcD. This molecule changes its helical twisting power (HTP) value in response to redox reactions. Therefore, in situ electrochemical redox reactions in the LC mixture allow for the device to change its reflection color in response to electrical stimuli. The LC mixture was introduced, by a capillary action, into a sandwich-type ITO glass cell comprising two glass slides with patterned indium tin oxide (ITO) electrodes, one of which was coated with poly(3,4-ethylenedioxythiophene)-co-poly(ethylene glycol) doped with perchlorate (PEDOT+). Upon application of +1.5 V, the reflection color of the device changed from blue (467 nm) to green (485 nm) in 0.4 s. Subsequent application of 0 V made the device recover the original blue color in 2.7 s. This device is characterized by its fastest electrical response and lowest operating voltage among any previously reported cholesteric LC device. This device could pave the way for the development of next generation reflective displays with low energy consumption rates.

A protocol for the fabrication of a reflective cholesteric liquid crystalline display device containing a redox-responsive chiral dopant allowing quick and low-voltage operation is presented.

一种用于快速和低压彩色调制的电化学胆固醇液晶器件

We demonstrate a method for fabricating a prototype reflective display device that contains cholesteric liquid crystal (LC) as an active component. The ...

Spectral and Angle-Resolved Magneto-Optical Characterization of Photonic Nanostructures

Photonic crystals are periodic nanostructures that can support a variety of confined electromagnetic modes. Such confined modes are usually accompanied by local enhancement of electric field intensity that strengthens light-matter interactions, enabling applications such as surface-enhanced Raman scattering (SERS) and surface plasmon enhanced sensing. In the presence of magneto-optically active materials, the local field enhancement gives rise to anomalous magneto-optical activity. Typically, the confined modes of a given photonic crystal depend strongly on the wavelength and incidence angle of the incident electromagnetic radiation. Thus, spectral and angular-resolved measurements are needed to fully identify them as well as to establish their relationship with the magneto-optical activity of the crystal. In this article, we describe how to use a Fourier-plane (back focal plane) microscope to characterize magneto-optically active samples. As a model system, here we use a plasmonic grating built out of magneto-optically active Au/Co/Au multilayer. In the experiments, we apply a magnetic field on the grating in situ and measure its reciprocal space response, obtaining the magneto-optical response of the grating over a range of wavelengths and incident angles. This information enables us to build a complete map of the plasmonic band structure of the grating and the angle and wavelength dependent magneto-optical activity. These two images allow us to pinpoint the effect that the plasmon resonances have on the magneto-optical response of the grating. The relatively small magnitude of magneto-optical effects requires a careful treatment of the acquired optical signals. To this end, an image processing protocol for obtaining magneto-optical response from the acquired raw data is laid out.

Photonic band structure enables understanding how confined electromagnetic modes propagate within a photonic crystal. In photonic crystals that incorporate magnetic elements, such confined and resonant optical modes are accompanied by enhanced and modified magneto-optical activity. We describe a measurement procedure to extract the magneto-optical band structure by Fourier space microscopy.

光子纳米结构的光谱和角度解析磁-光学特性

Photonic crystals are periodic nanostructures that can support a variety of confined electromagnetic modes. Such confined modes are usually accompanied by ...

High-Contrast and Fast Photorheological Switching of a Twist-Bend Nematic Liquid Crystal

Smart viscoelastic materials that respond to specific stimuli are one of the most attractive classes of materials important to future technologies, such as on-demand switchable adhesion technologies, actuators, molecular clutches, and nano-/microscopic mass transporters. Recently it was found that through a special solid-liquid transition, rheological properties can exhibit significant changes, thus providing suitable smart viscoelastic materials. However, designing materials with such a property is complex, and forward and backward switching times are usually long. Therefore, it is important to explore new working mechanisms to realize solid-liquid transitions, shorten the switching time, and enhance the contrast of rheological properties during switching. Here, a light-induced crystal-liquid phase transition is observed, which is characterized by means of polarizing light microscopy (POM), photorheometry, photo-differential scanning calorimetry (photo-DSC), and X-ray diffraction (XRD). The light-induced crystal-liquid phase transition presents key features such as (1) fast switching of crystal-liquid phases for both forward and backward reactions and (2) a high contrast ratio of viscoelasticity. In the characterization, POM is advantageous in offering information on the spatial distribution of LC molecule orientations, determining the type of liquid crystalline phases appearing in the material, and studying the orientation of LCs. Photorheometry allows measurement of a material&#8217;s rheological properties under light stimuli and can reveal the photorheological switching properties of materials. Photo-DSC is a technique to investigate thermodynamic information of materials in darkness and under light irradiation. Lastly, XRD allows studying of microscopic structures of materials. The goal of this article is to clearly present how to prepare and measure the discussed properties of a photorheological material.

This protocol demonstrates the preparation of a photorheological material that exhibits a solid phase, various liquid crystalline phases, and an isotropic liquid phase by increasing temperature. Presented here are methods for measuring the structure-viscoelasticity relationship of the material.

扭曲弯曲的液晶的高对比度和快速光圈开关

Smart viscoelastic materials that respond to specific stimuli are one of the most attractive classes of materials important to future technologies, such ...