这项工作得到了科技部台湾中华民国国家科技计划赞助NSC 103-2112-M-002-008-MY3的支持。

1.制造Microchip <ol><li> 制备ITO电极 <ol><li>使用商业插图软件绘制交叉图案。将对角电极之间的距离设置为160μm，并使十字图案的臂宽30 mm，长55 mm， 如图1所示。将插图文件保存为DXF文件。 </li><li>使用玻璃切割机将ITO玻璃修剪成尺寸为25 mm x 50 mm（宽x长）。使用75％乙醇和去离子水冲洗ITO玻璃几次。 </li><li>将ITO玻璃放在脉冲光纤激光打标机上。通过将ITO玻璃和激光之间的距离调整到279.5mm，将激光对焦在ITO玻璃的表面上。 注意:此处使用的激光器具有以下规格:1,064 nm，20 W，90至120 ns脉冲宽度和20至80 kHz脉冲重复频率，脉冲光强度约为5 x 10 5 W / cm 2）。 </li><li>直接将图示文件（DXF文件）输入激光打标机的计算机上。单击"标记参数"按钮，输入以下参数:速度"800 mm / s"权力"60％"和频率"40 kHz"。勾选"框架"，"填充"和"填充第一"条款。 <ol><li>点击"预览"按钮将图案放置在ITO玻璃中心。点击"标记样品"按钮对ITO玻璃进行图案化（ 图 1A ）。 </li></ol></li></ol></li><li> 设置四相发电机并连接实验微芯片 <ol><li>构建逆变器的电路，如图2A所示。 </li><li>通过与胶带直接接触将4根电线连接在四相电极上，如图2C所示。划分"通"el 1"的功能发生器分为两个分支，使用双BNC连接器。 <ol><li>将一个分支连接到连接到ITO电极的电线（＃1），另一个连接到逆变器的输入端。将反相器的输出连接到导线（＃3）， 如图2 B所示。 </li></ol></li><li>以与步骤1.2.2相同的步骤连接"通道2"，但如图2B所示连接到电线（＃2和＃4）。 </li><li>对于EROT实验，将两个通道之间的相移设置为90°，直接在函数发生器上。在实验过程中，以0.5-4 V pp电压振幅和频率范围为100 Hz至5 MHz施加正弦波， 如图2 D所示。 </li><li>对于DEP实验，将通道1的一个分支连接到连接到ITO电极的另一个线（＃1）输入反相器。将变频器的输出连接到电线（＃2）。使用相同的步骤连接通道2，但连接到电线（＃3和＃4）。 </li><li>在0°之间直接在函数发生器上设置2个通道之间的相移。在实验过程中，以0.5-4 V pp电压振幅和频率范围为100 Hz至5 MHz施加正弦波， 如图2 D所示。 </li></ol></li></ol> 2.准备样品<ol><li> Janus颗粒的制备 <ol><li>以2,200×g离心2μm二氧化硅颗粒水悬浮液（10％w / w）1分钟。 </li><li>将2μL沉淀二氧化硅颗粒吸入1.5 mL微量离心管中，加入500μL乙醇（99.5％v / v）。 注意:上清液不需要丢弃;只需将其保存在4°C的冰箱中即可。在pipettin之前不需要重新悬浮G。 </li><li>使用超声波仪（43kHz，50W）超声处理乙醇 - 二氧化硅颗粒悬浮液1分钟，然后以2200×g离心3分钟。 </li><li>用500μL乙醇代替上清液，重复步骤2.1.3三次。 </li><li>用8μL乙醇代替上清液，并使用超声波仪（43 kHz，50 W）超声处理乙醇 - 二氧化硅颗粒悬浮液3 min。 注意:在此步骤中约10μL乙醇 - 二氧化硅颗粒悬浮液应保留在管中。 </li><li>移取2μL乙醇 - 二氧化硅颗粒悬浮液，并将其放在普通玻璃载玻片（宽度:25mm，长度:75mm，厚度:1.2mm）上以形成液滴。 注意:这一数量的颗粒悬浮液足以制备5-6片幻灯片的单层（每张幻灯片2μL）。 </li><li>用玻璃杯缓慢地将乙醇 - 二氧化硅颗粒微滴略微地拉成二氧化硅颗粒单层（ 图3） </st荣&gt; A ）。 </li><li>将具有二氧化硅颗粒的单层的载玻片放入用Au涂覆的溅射装置中。 <ol><li>从100 mTorr的溅射室中取出空气，并注入氩气10分钟（用氩气代替空气）。停止注入氩气，然后从70 mTorr的室中取出氩气。 </li><li>将电流设置为15 mA，持续200 s。 （ 图 3B ）;在此步骤中已经准备了Janus颗粒。 </li></ol></li><li>在溅射的载玻片上滴入20μL去离子水，并使用正常的200μL移液管尖从单层刮掉Janus颗粒。 注意:在此步骤中，从单层刮掉的Janus颗粒悬浮在DI水滴中。 </li><li>移取Janus颗粒悬液液滴并滴入另一个1.5 mL离心管中。 </li><li>使用Janus颗粒悬浮液通过用DI水稀释至合适的浓度来制备样品为实验。 注意:本文所述实验中颗粒悬浮液的浓度约为2,000次/μL。 </li></ol></li><li> 完全涂覆金属颗粒的制备 14 <ol><li>以10:1的重量比混合PDMS聚合物基质和固化剂。 </li><li>围绕玻璃片粘贴以形成容器的侧壁。将PDMS的混合物倒入带胶片上以获得2-3mm的PDMS层， 如图4A所示。 </li><li>将胶带滑块（容器）与PDMS混合物放入气密室中，运行真空泵30分钟以除去PDMS混合物中的气泡。 </li><li>将带有PDMS混合物的胶带（容器）（步骤2.2.3）放入烤箱。在70℃下固化PDMS混合物2小时以形成PDMS印章。 </li><li> PDMS邮票固化后，取出幻灯片和胶带，以获取PDMS邮票，表面其最初附着在玻璃板上，形成平坦的表面，如图4B所示。 </li><li>按照2.1.1-2.1.8中的步骤在幻灯片上制备单层Janus粒子。 </li><li>使用PDMS邮票的平整表面均匀压印单层。 </li><li>将PDMS邮票与从步骤2.1.8中制作的载玻片倒置的Janus粒子单层进入待镀Au的溅射装置中。 <ol><li>从100 mTorr的溅射室中取出空气，并注入氩气10分钟（用氩气代替空气）。停止注入氩气，然后从70 mTorr的室中取出氩气。 </li><li>将电流设置为15 mA，持续200 s（ 图4 C ）;在该步骤中已经制备了完全涂覆的金属颗粒。 </li></ol></li><li>按照2.1.9-2.1.11中的步骤准备实验样品。 </li> &lt;/醇&gt; </li></ol>交流电动测量实验<ol><li> 包裹5片石蜡膜以制备间隔物。使用热枪将ITO电极阵列与厚度为500μm的膜间隔物结合，并将电极放置在显微镜载物台上。 <ol><li>将8μL在步骤2.1和2.2中制备的颗粒悬浮液滴到交叉电极阵列的中心。在隔片上放置一个盖玻片。 </li></ol></li><li> 对于EROT实验，在功能发生器上，将2个通道之间的相移设置为90°。在实验期间以0.5-4 V pp电压幅度和范围从100 Hz到5 MHz的频率施加正弦波（基于步骤1.2.2-1.2.3中的连接）。 <ol><li>通过单击函数发生器上的"波形"按钮选择波形。使用功能ge上的编号按钮输入电压和频率值然后点击"输出"按钮打开交流信号。 </li></ol></li><li>对于DEP实验，将2个通道之间的相移设置为0°。在实验期间（基于步骤1.2.5中的连接），以0.5-4 V pp电压幅度和频率100 Hz至5 MHz施加正弦波，方法如第3.2.1节中那样设置函数发生器。 </li><li>通过点击"输出"按钮打开交流信号，并使用相机用40X，NA 0.6物镜在倒置光学显微镜下捕获颗粒运动和旋转的图像。 </li><li>将粒子运动和旋转的图像输入到软件中，并通过粒子跟踪分析粒子的轨迹，以获得粒子和角速度。 注意:"Image J"软件及其"MultiTracker"插件用于图像二值化和粒子跟踪。 </li></ol>

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作者没有什么可以披露的。

使用光纤激光打标机制造ITO电极阵列提供了制备具有任意图案的电极的快速方法。然而，与通过传统方法制造的金属电极相比，该方法仍然存在诸如较少的电荷载体和较低的ITO电极的制造精度的缺点。这些缺点可能会限制一些实验。例如，当电极之间存在大的距离时，较少的载流子可能影响电场的分布。此外，图案化参数的调整是该方法中的关键步骤，其直接影响ITO电极阵列的质量。例如，激光?...

以罗马神命名为双面的Janus粒子是不对称的粒子，其双面在物理或化学上具有不同的表面性质1,2 。由于这种不对称特征，Janus颗粒在电场下表现出特殊的反应，例如DEP3,4,5,6，EROT2和诱导电荷电泳（ICEP） 7,8,9 。最近报道了几种制备Janus颗粒的方法，包括Pickering乳液法10 ，电动液体共喷射法11和微流体光聚合法12 。然而，这些方法需要一系列的组合提示设备和程序。本文介绍了一种简单的方法来制备Janus颗粒和完全涂覆的金属颗粒。在干燥过程中制备单层微尺度二氧化硅颗粒，并将其放入用Au涂覆的溅射装置中。颗粒的一个半球是阴影的，只有另一个半球涂有Au 2，13。 Janus颗粒的单层用聚二甲基硅氧烷（PDMS）印模冲压，然后用第二次涂覆工艺处理以制备完全涂覆的金属颗粒14 。 为了表征Janus颗粒的电学性质，不同的AC电动反应（如DEP，EROT和电取向）被广泛使用9,15,16,17,18 <s， 19 。例如，EROT是在外部施加的旋转电场2,9,15,16处的颗粒的稳态旋转响应。通过测量EROT，可以获得颗粒的感应偶极子与电场之间的相互作用。由诱发偶极子和不均匀电场之间的相互作用产生的DEP能够导致粒子运动3,4,5,9,15 。可以将不同种类的颗粒吸引到（正DEP）或排斥（负DEP）电极边缘，其用作操纵和表征微流体装置中的颗粒的一般方法。翻译（DEP）和旋转<html>电场下的粒子特征（EROT）分别由克劳修斯 - 莫索蒂（CM）因子的实部和虚部支配。 CM因子取决于粒子和周围液体的电学性质，从特征频率ωC =2σ/ aC DL ，DEP和EROT可知，其中σ是液体电导率，a是粒子半径， C DL是电双层15,16的电容。为了测量颗粒的EROT和DEP，需要特别设计的电极阵列图案。传统上，使用光刻技术来产生电极阵列并且需要一系列复杂的过程，包括光刻胶旋涂，掩模对准，曝光和显影15,18 ，s ="xref"&gt; 19，20。 在本文中，电极阵列的快速制造通过直接光学图案化来证明。通过光纤激光打标机（1,064nm，20W，90〜120ns脉冲宽度，20〜80kHz脉冲重复频率）部分地除去涂布在玻璃基板上的透明薄膜ITO层，形成四相电极阵列。对角电极之间的距离为150-800μm，可以进行调整以适应实验。四相电极阵列可用于表征和浓缩不同微流体装置15,16,18中的颗粒。为了产生四相电场，电极阵列连接到2通道功能发生器和两个反相器。相邻电极之间的相移设置为90°（对于EROT）或180°（DEP） 15 。 AC信号以0.5至4 V pp电压幅度施加，运行过程中频率范围为100 Hz至5 MHz。将Janus颗粒，金属颗粒和二氧化硅颗粒用作样品以测量其AC电动性质。将颗粒的悬浮液放置在电极阵列的中心区域，并在具有40X，NA 0.6目标的倒置光学显微镜下观察。使用数码相机记录颗粒运动和旋转。 DEP运动被记录在径向远离阵列中心的40至65μm之间的环形区域处，并且EROT被记录在径向远离阵列中心的圆形区域65μm处。颗粒速度和角速度通过粒子跟踪方法测量。粒子质心通过灰度或使用软件的粒子几何来区分。粒子速度和角速度由测量粒子质心的运动。 本文提供了一种快速制造任意图案化电极阵列的简单方法。它介绍了完全或部分涂覆的金属颗粒的制备，可用于不同领域，从生物学到工业应用。

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			<td>1.5ml</td>
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preparation of janus particles and alternating current electrokinetic measurements with a rapidly fabricated indium tin oxide electrode array

本文提供了一种制备部分或完全涂覆的金属颗粒并执行电极阵列的快速制造的简单方法，其可以促进微流体装置中的电学实验。 Janus颗粒是在其两侧含有两种不同表面性质的不对称颗粒。为了制备Janus颗粒，通过干燥过程制备单层二氧化硅颗粒。使用溅射装置将金（Au）沉积在每个颗粒的一侧上。完全涂覆的金属颗粒在第二次涂覆工艺之后完成。为了分析Janus粒子的电气表面性质，进行了在实验装置中需要专门设计的电极阵列的交流电（AC）电动力学测量，例如介电电泳（DEP）和电旋转（EROT）。然而，制造电极阵列的传统方法，例如光刻技术，需要一系列的复杂程序。在这里，我们介绍一种灵活的方法来制造设计的电极阵列。通过光纤激光打标机（1,064nm，20W，脉冲宽度为90〜120ns，脉冲重复频率为20〜80kHz）对铟锡氧化物（ITO）玻璃进行图案化，形成四相电极阵列。为了产生四相电场，电极连接到2通道功能发生器和两个反相器。相邻电极之间的相移设置为90°（对于EROT）或180°（对于DEP）。提出了具有四相ITO电极阵列的交流电动测量的代表性结果。

四相电极阵列由光纤激光打标机产生。通过聚焦激光去除涂覆在玻璃上的ITO导电层，形成间隙为160μm的交叉图案， 如图1B所示。 <img alt="图1" class="xfigimg" src="/files/ftp_upload/55950/55950fig1.jpg" /> 图1 :ITO电极的制备。 （ A ）使用光纤激光打标机（1,064nm，20W，9...

Watch this Scientific Journal Video about Preparation of Janus Particles and Alternating Current Electrokinetic Measurements with a Rapidly Fabricated Indium Tin Oxide Electrode Array at JoVE.com

Preparation of Janus Particles and Alternating Current Electrokinetic Measurements with a Rapidly Fabricated Indium Tin Oxide Electrode Array

在本文中，证明了使用快速制造的氧化铟锡（ITO）电极阵列制备部分或完全涂覆的金属颗粒和进行交流电动特性测量的简单方法。

使用快速制造的氧化铟锡电极阵列制备Janus粒子和交流电动势测量

This article provides a simple method to prepare partially or fully coated metallic particles and to perform the rapid fabrication of electrode arrays, ...

preparation-janus-particles-alternating-current-electrokinetic

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Education

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Electrical Engineering

Engineering

Unit 1

AC Circuit Analysis

SCIENTISTS IN ACTION

8.1K 次观看.  National Taiwan University. 在本文中，证明了使用快速制造的氧化铟锡（ITO）电极阵列制备部分或完全涂覆的金属颗粒和进行交流电动特性测量的简单方法。 

视频: Preparation of Janus Particles and Alternating Current Electrokinetic Measurements with a Rapidly Fabricated Indium Tin Oxide Electrode Array

Probing and Mapping Electrode Surfaces in Solid Oxide Fuel Cells

Solid oxide fuel cells (SOFCs) are potentially the most efficient and cost-effective solution to utilization of a wide variety of fuels beyond hydrogen 1-7. The performance of SOFCs and the rates of many chemical and energy transformation processes in energy storage and conversion devices in general are limited primarily by charge and mass transfer along electrode surfaces and across interfaces. Unfortunately, the mechanistic understanding of these processes is still lacking, due largely to the difficulty of characterizing these processes under in situ conditions. This knowledge gap is a chief obstacle to SOFC commercialization. The development of tools for probing and mapping surface chemistries relevant to electrode reactions is vital to unraveling the mechanisms of surface processes and to achieving rational design of new electrode materials for more efficient energy storage and conversion2. Among the relatively few in situ surface analysis methods, Raman spectroscopy can be performed even with high temperatures and harsh atmospheres, making it ideal for characterizing chemical processes relevant to SOFC anode performance and degradation8-12. It can also be used alongside electrochemical measurements, potentially allowing direct correlation of electrochemistry to surface chemistry in an operating cell. Proper in situ Raman mapping measurements would be useful for pin-pointing important anode reaction mechanisms because of its sensitivity to the relevant species, including anode performance degradation through carbon deposition8, 10, 13, 14 ("coking") and sulfur poisoning11, 15 and the manner in which surface modifications stave off this degradation16. The current work demonstrates significant progress towards this capability. In addition, the family of scanning probe microscopy (SPM) techniques provides a special approach to interrogate the electrode surface with nanoscale resolution. Besides the surface topography that is routinely collected by AFM and STM, other properties such as local electronic states, ion diffusion coefficient and surface potential can also be investigated17-22. In this work, electrochemical measurements, Raman spectroscopy, and SPM were used in conjunction with a novel test electrode platform that consists of a Ni mesh electrode embedded in an yttria-stabilized zirconia (YSZ) electrolyte. Cell performance testing and impedance spectroscopy under fuel containing H2S was characterized, and Raman mapping was used to further elucidate the nature of sulfur poisoning. In situ Raman monitoring was used to investigate coking behavior. Finally, atomic force microscopy (AFM) and electrostatic force microscopy (EFM) were used to further visualize carbon deposition on the nanoscale. From this research, we desire to produce a more complete picture of the SOFC anode.

We present a unique platform for characterizing electrode surfaces in solid oxide fuel cells (SOFCs) that allows simultaneous performance of multiple characterization techniques (e.g. in situ Raman spectroscopy and scanning probe microscopy alongside electrochemical measurements). Complementary information from these analyses may help to advance toward a more profound understanding of electrode reaction and degradation mechanisms, providing insights into rational design of better materials for SOFCs.

在固体氧化物燃料电池电极表面的探测和测绘

Solid oxide fuel cells (SOFCs) are potentially the most efficient and cost-effective solution to utilization of a wide variety of fuels beyond hydrogen ...

科研

工程学

Characterization of Electrode Materials for Lithium Ion and Sodium Ion Batteries Using Synchrotron Radiation Techniques

Intercalation compounds such as transition metal oxides or phosphates are the most commonly used electrode materials in Li-ion and Na-ion batteries. During insertion or removal of alkali metal ions, the redox states of transition metals in the compounds change and structural transformations such as phase transitions and/or lattice parameter increases or decreases occur. These behaviors in turn determine important characteristics of the batteries such as the potential profiles, rate capabilities, and cycle lives. The extremely bright and tunable x-rays produced by synchrotron radiation allow rapid acquisition of high-resolution data that provide information about these processes. Transformations in the bulk materials, such as phase transitions, can be directly observed using X-ray diffraction (XRD), while X-ray absorption spectroscopy (XAS) gives information about the local electronic and geometric structures (e.g.&#160;changes in redox states and bond lengths). In situ experiments carried out on operating cells are particularly useful because they allow direct correlation between the electrochemical and structural properties of the materials. These experiments are time-consuming and can be challenging to design due to the reactivity and air-sensitivity of the alkali metal anodes used in the half-cell configurations, and/or the possibility of signal interference from other cell components and hardware. For these reasons, it is appropriate to carry out ex situ experiments (e.g.&#160;on electrodes harvested from partially charged or cycled cells) in some cases. Here, we present detailed protocols for the preparation of both ex situ and in situ samples for experiments involving synchrotron radiation and demonstrate how these experiments are done.

We describe the use of synchrotron X-ray absorption spectroscopy (XAS) and X-ray diffraction (XRD) techniques to probe details of intercalation/deintercalation processes in electrode materials for Li-ion and Na-ion batteries. Both in situ and ex situ experiments are used to understand structural behavior relevant to the operation of devices

正极材料的同步辐射技术锂离子和钠离子电池表征

Intercalation compounds such as transition metal oxides or phosphates are the most commonly used electrode materials in Li-ion and Na-ion batteries. ...

Development of a 3D Graphene Electrode Dielectrophoretic Device

The design and fabrication of a novel 3D electrode microdevice using 50 &#181;m thick graphene paper and 100 &#181;m double sided tape is described. The protocol details the procedures to construct a versatile, reusable, multiple layer, laminated dielectrophoresis chamber. Specifically, six layers of 50 &#181;m x&#160;0.7 cm x&#160;2 cm graphene paper and five layers of double sided tape were alternately stacked together, then clamped to a glass slide. Then a 700 &#956;m diameter micro-well was drilled through the laminated structure using a computer-controlled micro drilling machine. Insulating properties of the tape layer between adjacent graphene layers were assured by resistance tests. Silver conductive epoxy connected alternate layers of graphene paper and formed stable connections between the graphene paper and external copper wire electrodes. The finished device was then clamped and sealed to a glass slide. The electric field gradient was modeled within the multi-layer device. Dielectrophoretic behaviors of 6 &#956;m polystyrene beads were demonstrated in the 1 mm deep micro-well, with medium conductivities ranging from 0.0001 S/m to 1.3 S/m, and applied signal frequencies from 100 Hz to 10 MHz. Negative dielectrophoretic responses were observed in three dimensions over most of the conductivity-frequency space and cross-over frequency values are consistent with previously reported literature values. The device did not prevent AC electroosmosis and electrothermal flows, which occurred in the low and high frequency regions, respectively. The graphene paper utilized in this device is versatile and could subsequently function as a biosensor after dielectrophoretic characterizations are complete.

A microdevice with high throughput potential is used to demonstrate three-dimensional (3D) dielectrophoresis (DEP) with novel materials. Graphene nanoplatelet paper and double sided tape were alternately stacked; a 700 &#956;m micro-well was drilled transverse to the layers. DEP behavior of polystyrene beads was demonstrated in the micro-well.

三维石墨电极介电泳装置的研制

The design and fabrication of a novel 3D electrode microdevice using 50 &#181;m thick graphene paper and 100 &#181;m double sided tape is described. The ...

Writing and Low-Temperature Characterization of Oxide Nanostructures

Oxide nanoelectronics is a rapidly growing field which seeks to develop novel materials with multifunctional behavior at nanoscale dimensions. Oxide interfaces exhibit a wide range of properties that can be controlled include conduction, piezoelectric behavior, ferromagnetism, superconductivity and nonlinear optical properties. Recently, methods for controlling these properties at extreme nanoscale dimensions have been discovered and developed. Here are described explicit step-by-step procedures for creating LaAlO3/SrTiO3 nanostructures using a reversible conductive atomic force microscopy technique. The processing steps for creating electrical contacts to the LaAlO3/SrTiO3 interface are first described. Conductive nanostructures are created by applying voltages to a conductive atomic force microscope tip and locally switching the LaAlO3/SrTiO3 interface to a conductive state. A versatile nanolithography toolkit has been developed expressly for the purpose of controlling the atomic force microscope (AFM) tip path and voltage. Then, these nanostructures are placed in a cryostat and transport measurements are performed. The procedures described here should be useful to others wishing to conduct research in oxide nanoelectronics.

Oxide nanostructures provide new opportunities for science and technology. The interfacial conductivity between LaAlO3 and SrTiO3 can be controlled with near-atomic precision using a conductive atomic force microscopy technique. The protocol for creating and measuring conductive nanostructures at LaAlO3/SrTiO3 interfaces is demonstrated.

写作和氧化物纳米结构的低温特性

Oxide nanoelectronics is a rapidly growing field which seeks to develop novel materials with multifunctional behavior at nanoscale dimensions.  Oxide ...

Preparation and Friction Force Microscopy Measurements of Immiscible, Opposing Polymer Brushes

Solvated polymer brushes are well known to lubricate high-pressure contacts, because they can sustain a positive normal load while maintaining low friction at the interface. Nevertheless, these systems can be sensitive to wear due to interdigitation of the opposing brushes. In a recent publication, we have shown via molecular dynamics simulations and atomic force microscopy experiments, that using an immiscible polymer brush system terminating the substrate and the slider surfaces, respectively, can eliminate such interdigitation. As a consequence, wear in the contacts is reduced. Moreover, the friction force is two orders of magnitude lower compared to traditional miscible polymer brush systems. This newly proposed system therefore holds great potential for application in industry. Here, the methodology to construct an immiscible polymer brush system of two different brushes each solvated by their own preferred solvent is presented. The procedure how to graft poly(N-isopropylacrylamide) (PNIPAM) from a flat surface and poly(methyl methacrylate) (PMMA) from an atomic force microscopy (AFM) colloidal probe is described. PNIPAM is solvated in water and PMMA in acetophenone. Via friction force AFM measurements, it is shown that the friction for this system is indeed reduced by two orders of magnitude compared to the miscible system of PMMA on PMMA solvated in acetophenone.

The methodology to perform friction force microscopy experiments for contacting brushes is presented: Two polymer brushes that are grafted from (a) substrates and (b) colloidal probes are slid to show that, by using two contacting immiscible brush systems, friction in sliding contacts is reduced compared to miscible brush systems.

互溶的测量准备和摩擦力显微镜，反对聚合物刷

Solvated polymer brushes are well known to lubricate high-pressure contacts, because they can sustain a positive normal load while maintaining low ...

Ultrasound Velocity Measurement in a Liquid Metal Electrode

A growing number of electrochemical technologies depend on fluid flow, and often that fluid is opaque. Measuring the flow of an opaque fluid is inherently more difficult than measuring the flow of a transparent fluid, since optical methods are not applicable. Ultrasound can be used to measure the velocity of an opaque fluid, not only at isolated points, but at hundreds or thousands of points arrayed along lines, with good temporal resolution. When applied to a liquid metal electrode, ultrasound velocimetry involves additional challenges: high temperature, chemical activity, and electrical conductivity. Here we describe the experimental apparatus and methods that overcome these challenges and allow the measurement of flow in a liquid metal electrode, as it conducts current, at operating temperature. Temperature is regulated within &#177;2 &#176;C using a Proportional-Integral-Derivative (PID) controller that powers a custom-built furnace. Chemical activity is managed by choosing vessel materials carefully and enclosing the experimental setup in an argon-filled glovebox. Finally, unintended electrical paths are carefully prevented. An automated system logs control settings and experimental measurements, using hardware trigger signals to synchronize devices. This apparatus and these methods can produce measurements that are impossible with other techniques, and allow optimization and control of electrochemical technologies like liquid metal batteries.

Ultrasound velocimetry is used to study mixing by fluid flow in liquid metal electrodes. The focus of this manuscript is to illustrate the methods used for making precise, spatially-resolved ultrasound measurements while limiting oxidation and controlling and monitoring temperature, applied current, and the heater power being supplied.

超声速度测量的液态金属电极

A growing number of electrochemical technologies depend on fluid flow, and often that fluid is opaque. Measuring the flow of an opaque fluid is inherently ...

Surface Enhanced Raman Spectroscopy Detection of Biomolecules Using EBL Fabricated Nanostructured Substrates

Fabrication and characterization of conjugate nano-biological systems interfacing metallic nanostructures on solid supports with immobilized biomolecules is reported. The entire sequence of relevant experimental steps is described, involving the fabrication of nanostructured substrates using electron beam lithography, immobilization of biomolecules on the substrates, and their characterization utilizing surface-enhanced Raman spectroscopy (SERS). Three different designs of nano-biological systems are employed, including protein A, glucose binding protein, and a dopamine binding DNA aptamer. In the latter two cases, the binding of respective ligands, D-glucose and dopamine, is also included. The three kinds of biomolecules are immobilized on nanostructured substrates by different methods, and the results of SERS imaging are reported. The capabilities of SERS to detect vibrational modes from surface-immobilized proteins, as well as to capture the protein-ligand and aptamer-ligand binding are demonstrated. The results also illustrate the influence of the surface nanostructure geometry, biomolecules immobilization strategy, Raman activity of the molecules and presence or absence of the ligand binding on the SERS spectra acquired.

We describe the fabrication and characterization of nano-biological systems interfacing nanostructured substrates with immobilized proteins and aptamers. The relevant experimental steps involving lithographic fabrication of nanostructured substrates, bio-functionalization, and surface-enhanced Raman spectroscopy (SERS) characterization, are reported. SERS detection of surface-immobilized proteins, and probing of protein-ligand and aptamer-ligand binding is demonstrated.

表面增强拉曼光谱检测生物分子利用EBL装配纳米衬底

Fabrication and characterization of conjugate nano-biological systems interfacing metallic nanostructures on solid supports with immobilized biomolecules ...

Iridium Oxide-reduced Graphene Oxide Nanohybrid Thin Film Modified Screen-printed Electrodes as Disposable Electrochemical Paper Microfluidic pH Sensors

A facile, controllable, inexpensive and green electrochemical synthesis of IrO2-graphene nanohybrid thin films is developed to fabricate an easy-to-use integrated paper microfluidic electrochemical pH sensor for resource-limited settings. Taking advantages from both pH meters and strips, the pH sensing platform is composed of hydrophobic barrier-patterned paper micropad (&#181;PAD) using polydimethylsiloxane (PDMS), screen-printed electrode (SPE) modified with IrO2-graphene films and molded acrylonitrile butadiene styrene (ABS) plastic holder. Repetitive cathodic potential cycling was employed for graphene oxide (GO) reduction which can completely remove electrochemically unstable oxygenated groups and generate a 2D defect-free homogeneous graphene thin film with excellent stability and electronic properties. A uniform and smooth IrO2 film in nanoscale grain size is anodically electrodeposited onto the graphene film, without any observable cracks. The resulting IrO2-RGO electrode showed slightly super-Nernstian responses from pH 2-12 in Britton-Robinson (B-R) buffers with good linearity, small hysteresis, low response time and reproducibility in different buffers, as well as low sensitivities to different interfering ionic species and dissolved oxygen. A simple portable digital pH meter is fabricated, whose signal is measured with a multimeter, using high input-impedance operational amplifier and consumer batteries. The pH values measured with the portable electrochemical paper-microfluidic pH sensors were consistent with those measured using a commercial laboratory pH meter with a glass electrode.

The study demonstrates the growth of iridium oxide-reduced graphene oxide (IrO2-RGO) nanohybrid thin films on irregular and rough screen-printed carbon substrate through a green electrochemical synthesis, and their implementation as a pH sensor with a patterned paper-fluidic platform.

氧化铱还原氧化石墨烯纳米杂化薄膜修饰丝网印刷电极一次性电化学微流控纸pH传感器

A facile, controllable, inexpensive and green electrochemical synthesis of IrO2-graphene nanohybrid thin films is developed to fabricate an easy-to-use ...

Non-aqueous Electrode Processing and Construction of Lithium-ion Coin Cells

Research into new and improved materials to be utilized in lithium-ion batteries (LIB) necessitates an experimental counterpart to any computational analysis. Testing of lithium-ion batteries in an academic setting has taken on several forms, but at the most basic level lies the coin cell construction. In traditional LIB electrode preparation, a multi-phase slurry composed of active material, binder, and conductive additive is cast out onto a substrate. An electrode disc can then be punched from the dried sheet and used in the construction of a coin cell for electrochemical evaluation. Utilization of the potential of the active material in a battery is critically dependent on the microstructure of the electrode, as an appropriate distribution of the primary components are crucial to ensuring optimal electrical conductivity, porosity, and tortuosity, such that electrochemical and transport interaction is optimized. Processing steps ranging from the combination of dry powder, wet mixing, and drying can all critically affect multi-phase interactions that influence the microstructure formation. Electrochemical probing necessitates the construction of electrodes and coin cells with the utmost care and precision. This paper aims at providing a step-by-step guide of non-aqueous electrode processing and coin cell construction for lithium-ion batteries within an academic setting and with emphasis on deciphering the influence of drying and calendaring.

Non-aqueous electrode processing is central to the construction of coin cells and the evaluation of new electrode chemistries for lithium-ion batteries. A step-by-step guide to the basic practices needed as an electrochemical engineer working with batteries in an academic experimental setting is furnished.

锂离子纽扣电池的非水电极加工和施工

Research into new and improved materials to be utilized in lithium-ion batteries (LIB) necessitates an experimental counterpart to any computational ...

Methods for Measuring the Orientation and Rotation Rate of 3D-printed Particles in Turbulence

Experimental methods are presented for measuring the rotational and translational motion of anisotropic particles in turbulent fluid flows. 3D printing technology is used to fabricate particles with slender arms connected at a common center. Shapes explored are crosses (two perpendicular rods), jacks (three perpendicular rods), triads (three rods in triangular planar symmetry), and tetrads (four arms in tetrahedral symmetry). Methods for producing on the order of 10,000 fluorescently dyed particles are described. Time-resolved measurements of their orientation and solid-body rotation rate are obtained from four synchronized videos of their motion in a turbulent flow between oscillating grids with R&#955; = 91. In this relatively low-Reynolds number flow, the advected particles are small enough that they approximate ellipsoidal tracer particles. We present results of time-resolved 3D trajectories of position and orientation of the particles as well as measurements of their rotation rates.

We use 3D printing to fabricate anisotropic particles in the shapes of jacks, crosses, tetrads, and triads, whose alignments and rotations in turbulent fluid flow can be measured from multiple simultaneous video images.

测量的方向和旋转速率方法3D打印在湍流颗粒

Experimental methods are presented for measuring the rotational and translational motion of anisotropic particles in turbulent fluid flows. 3D printing ...