这项工作得到了美国国家科学基金会（NSF CHE-1847830）的支持。

1. 制作聚乙烯醇（PVA）溶液
<ol><li>测量水和 PVA 聚合物颗粒（参见 材料表），以 20% PVA 与水的重量比制备 10 mL 溶液。</li>
	<li>在设置为100°C的热板上加热玻璃器皿中的水。</li>
	<li>将PVA聚合物颗粒放入热水中。插入磁力搅拌棒。</li>
	<li>将热量降低至80°C，搅拌至PVA完全溶解。</li>
	<li>盖住玻璃器皿的顶部以防止污染。</li>
	<li>完全溶解后，将 20% PVA 溶液放入适当的储存容器中，在室温下储存。</li>
</ol>2. 制备PVA涂层硅（Si）晶圆
<ol><li>将硅 （Si） 晶圆（见 材料表）切成 ~10 x 10 mm2 正方形。</li>
	<li>使用异丙醇清洁硅基板并使其干燥。</li>
	<li>将干净的硅晶圆放在旋涂机的卡盘上（参见 材料表）。<ol><li>将大约 10 μL PVA 溶液滴注到 Si 衬底的中心。尽量避免气泡形成。</li>
		<li>以每分钟 1,500 转 （rpm） 的速度旋转涂覆 30 秒，用均匀的 PVA 薄膜涂覆 Si 基板。 注意:指定的液体体积和旋涂参数在基材表面形成一层均匀的 PVA，其厚度足以防止旋涂和下一步将 PS 珠子放置到 PVA 表面之间快速干燥。</li>
	</ol></li>
	<li>在转移PS微珠之前，从旋涂机中取出样品并将其放入干净的样品容器中，以防止污染。</li>
</ol>3. 将 PS 珠子放在 PVA 涂层表面上
<ol><li>使用异丙醇清洁硅基板并使其干燥。</li>
	<li>使用移液管，将悬浮在水中的 1 μL PS 珠放在基材的中心。</li>
	<li>将样品放入装有膨润土粘土干燥剂的储藏室中，让水蒸发。 注意:此步骤通过减少暴露于潮湿环境中来保存样品。</li>
	<li>将PVA涂层的基材（步骤2.4）和带有干燥的PS珠的基材（步骤3.3）置于光学显微镜下。根据它们的大小，使用简单的双筒望远镜可以看到单个珠子，或者需要更高的光学放大倍率。</li>
	<li>使用超细镊子轻轻松开珠子（参见 材料表）。用细毛画笔收集一些松散的珠子，然后轻轻敲击新涂有 PVA 涂层的晶圆上的画笔毛发。多次扫描应使珠子积聚在刷子的毛发中。轻敲画笔毛发的顶部以扰乱 PS 珠粉，将珠子释放到粘性 PVA 表面上。 注意: 重要的是画笔是高质量和干净的，以避免将纤维和污染物释放到 PVA 薄膜的表面。在此步骤中快速移动是必不可少的，这样 PVA 就不会完全干燥。</li>
	<li>重复此步骤，直到通过光学显微镜检查确认单个 PS 珠粘附在 PVA 表面上。</li>
	<li>将样品储存在干净的容器中。让样品完全干燥。 注意:在进行进一步的分析尝试之前，应让样品完全冷却和干燥。AFM高度测量或表面轮廓仪测量可以评估连续PVA薄膜的厚度。</li>
</ol>4. 加载样品进行AFM表征
注意:所描述的协议基于nanoIR2（参见 材料表）平台的标准操作程序，但应根据用于测量的AFM模型进行调整。
<ol><li>使用金属 AFM 盘和粘性标签将 PVA 和 PS 微珠样品安装到 AFM 载物台上，以便样品牢固地固定在样品架上。</li>
	<li>将nanoIR探针（例如FORTGG）安装到AFM探针支架上。 注:AFM 悬臂长 225 μm，宽 27 μm，厚 2.7 μm，尖端半径小于 10 nm。悬臂的两侧涂有 45 nm 厚的金膜，以限制其对样品顶部红外照明的响应（参见 材料表）。对于纳米红外光谱测量，最好使用在使用前已储存在无聚二甲基硅氧烷环境中的悬臂。</li>
	<li>通过转动激光对准旋钮（激光位置的 x 和 y 调整以及探测器位置的垂直调整），将读出的激光器对准悬臂光束的自由端。<ol><li>最大化检测器的 SUM 信号。</li>
		<li>通过转动偏转旋钮来调整检测器的位置，使激光与AFM读出系统的位置敏感检测器的中心对齐，对应于~0V的垂直偏转信号。</li>
	</ol></li>
	<li>单击AFM"探针"控制面板中的 "加载 "图标。<ol><li>按照向导屏幕中的提示进行操作。使用 聚焦箭头 确定 nanoIR 悬臂的焦平面。使用 XY 位移控件将悬臂定位在屏幕中央（与白色十字对齐）。</li>
		<li>接下来，单击 焦点箭 头以找到样品表面的焦平面。</li>
		<li>使用系统的光学视图和 XY 位移控制将悬臂尖端定位在感兴趣的磁珠上方，然后单击 下一步。</li>
		<li>在接合屏幕上，将"对峙"设置为 50 μm ，然后单击 Approach Only。</li>
	</ol></li>
	<li>启动 Engage 程序以接近尖端进行成像。</li>
</ol>5. 创建多聚物样品的形貌和纳米红外图像
<ol><li>在标准"接触模式"下采集形貌图像。设置悬臂相对于 PS 磁珠的位置后，通过单击 AFM"探头"控制面板中的 啮合 图标来启动进近。整个研究使用了 0.2 V 偏转差的啮合设定值，对应于 ~100 nN 的力。 在AFM"扫描"控制面板中，将 扫描速率 设置为0.8 Hz， 扫描大小 （高度和宽度）以及用于成像 的每行点数和每张图像的行数 （此处使用512 x 512）。单击"扫描"以获取地形图像。 注:悬臂18 的校准是通过确定悬臂与蓝宝石衬底相互作用时获得的挠度-距离曲线斜率的偏转灵敏度（以nm/V为单位）来完成的（补充图1A）。悬臂刚度由热调谐19 确定（补充图1B）。悬臂的共振是使用洛伦兹函数拟合的。悬臂刚度（单位:N/m）使用均分定理 <img alt="Equation 1" src="/files/ftp_upload/65357/65357eq01.jpg" style="margin: auto;">确定，其中 KB是玻尔兹曼常数，T是温度（T = 295K），P是悬臂热波动的功率谱面积，通过对热调谐数据20的洛伦兹拟合进行积分确定。</li>
	<li>对于nanoIR测量，将AFM尖端放在从形貌图像中识别的感兴趣特征上。<ol><li>选择nanoIR控制面板中的 音叉 图标，以确定悬臂的接触谐振频率。设置一个照明波数，以激发材料中的光热膨胀。设置要扫描的激光脉冲频率范围，并设置nanoIR激光器的占空比。在"激光脉冲调谐窗口"中选择 采集 。</li>
		<li>通过将标记条（绿色垂直线）定位在第二个接触谐振的峰值处，选择尖端样品系统的第二个接触共振以进行 nanoIR 测量。 注意: 接触共振模式的选择可能因悬臂和样品的类型而异。</li>
		<li>单击" 优化 "（Optimize），将红外激光焦点区域的中心与悬臂尖端的位置对齐。对准是在选定的红外照明波数下完成的，对应于探测材料的吸收带。悬臂位于激光足迹的中心（补充图2）。 注意: 根据激光型号的不同，不同波数的对准可能会有所不同。</li>
		<li>获取红外激光照明的背景。这包括在所选脉冲频率下测量红外量子级联激光器（QCL）在发射波长范围内的输出（补充图3）。这对于nanoIR光谱的背景校正非常重要。</li>
		<li>通过选择波数范围（此处， 开始 和 停止 分别设置为 1,530 cm-1 和 1,800 cm-1）、 步长 （2 cm-1） 和用于测量 的平均值数 来获取 nanoIR 光谱。通过将衰减背景测量的光热振幅除以显示的光谱进行背景校正，其中包括将步骤5.2.4中收集的背景乘以为测量选择的功率百分比。</li>
	</ol></li>
	<li>对于 nanoIR 成像，选择 感兴趣的成像区域 。<ol><li>在"激光脉冲调谐窗口"（通过音叉图标访问）中启用锁相环 （PLL） 自动调谐。</li>
		<li>调整最小和最大频率以在常规控制面板中以第二谐振模式为中心的扫描范围。</li>
		<li>通过单击PLL控制面板中的 零 来将相位归零，然后单击"激光脉冲调谐窗口"中的 "确定 "。</li>
		<li>通过在 nanoIR 控制面板的框中打勾来选择 IR Imaging Enabled 。</li>
		<li>在"成像视图"控制面板中，选择 高度 （成像视图 1）、 振幅 2 （成像视图 2）和 相位 2 （成像视图 3）以获取样品的形貌和化学图像。将采集方向设置为 "跟踪 "（或 "跟踪"）。通常需要 线拟合 线来观察所采集样品的形貌图像。捕获拟合度应设置为 "无"。 注意:可以根据需要调整扫描首选项，例如捕获的扫描方向或使用的调色板。</li>
		<li>在AFM"扫描"控制面板中，选择 扫描 图标。</li>
		<li>要保存图像，请在"捕获"控制面板中选择 "现在 "或 "帧结束 "图标。</li>
	</ol></li>
	<li>要导出数据，请右键单击数据列表中的图像或光谱文件名。选择 "导出" ，然后选择要导出的文件格式。将文件保存在所需的计算机文件夹位置。</li>
</ol>

通过纳米级红外光谱探索多相聚合物系统

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作者没有什么可透露的。

AFM与nanoIR光谱相结合，可以使用接触模式的悬臂和脉冲可调谐红外光源提供纳米级化学信息。模型系统，例如在聚合物材料的体积中嵌入具有有限尺寸的吸收器，对于提高对图像形成机制的理解和确定工具的性能非常重要。在本文介绍的PS/PVA配置的情况下，进行了优化以获得位于PVA薄膜表面上方或下方的稳定PS珠。结果发现，从旋涂机上取下涂覆的Si基材后立即沉积PS微珠可产生更好的附着力。PVA?...

原子力显微镜 （AFM） 对于以纳米级分辨率1、2、3 对各种样品的形态进行成像和表征至关重要。通过测量针尖与样品表面相互作用导致的悬臂挠度，已经开发了用于局部刚度测量和针尖-样品粘附的纳米级功能成像协议4,5。对于软凝聚态物质和聚合物分析，探索局部域的纳米力学和纳米化学性质的AFM测量备受追捧6,7,8。在纳米级红外 （nanoIR） 光谱出现之前，对针尖进行了化学修饰，以评估 AFM 力曲线中不同域的存在，并推断针尖-样品相互作用的性质。例如，该方法用于揭示环己烷处理的聚苯乙烯嵌段聚（丙烯酸叔丁酯）嵌段共聚物薄膜表面聚（丙烯酸叔丁酯）嵌段共聚物薄膜表面的微结构域的转变，该薄膜在50nm以下的水平9。
红外 （IR） 光与 AFM 的结合对高分子科学领域产生了重大影响6.传统的红外光谱是研究聚合物材料化学结构的广泛使用的技术10,11，但它无法提供有关单个相和相间行为的信息，因为与用于探测样品的红外光束的大小相比，这些区域太小。这个问题适用于红外显微光谱，因为它受到光学衍射极限6的限制。这种测量平均了红外光激发的整个区域的贡献;探测区域内存在纳米级相所产生的信号要么表现出复杂的指纹，在后处理过程中应进行去卷积处理，要么由于信号电平低于可检测电平而丢失。因此，开发具有纳米级空间分辨率和高红外灵敏度的工具来探索复杂介质中的纳米级化学特征至关重要。
已经开发了实现纳米红外光谱的方案，首先使用金属原子力显微镜尖端作为纳米天线12,13，最近利用悬臂悬臂监测样品12,14,15红外照明期间发生的光热膨胀变化的能力。后者使用脉冲、可调谐的红外光源，该光源调谐到探测材料的吸收带，使样品吸收辐射并发生光热膨胀。这种方法非常适合有机和聚合物材料。脉冲激发使原子力显微镜悬臂以振荡的形式与样品表面接触时可以检测到这种效应。然后，在频谱中观察到的系统接触共振之一的振幅作为照明波长的函数进行监测，该波长构成了AFM尖端15下方材料的nanoIR吸收光谱。纳米红外成像和光谱学的空间分辨率受到材料光热膨胀的各种影响的限制。已经评估了使用接触模式AFM的光热纳米IR光谱可以获得具有亚50nm尺度空间分辨率的材料的振动吸收光谱特性14，最近的工作证明了α-突触核蛋白16,17的单体和二聚体的检测。然而，对以各种构型组装的非均相聚合物材料进行纳米红外测量性能的定量研究仍然有限，例如嵌入各种聚合物薄膜体积中的有限尺寸的吸收器的情况。
本文旨在创建一个具有已知尺寸嵌入特征的聚合物组件，以评估表面分析过程中 nanoIR 的光热膨胀灵敏度和空间分辨率。该协议涵盖了在硅衬底上制备聚乙烯醇（PVA）聚合物薄膜以及将三维聚苯乙烯（PS）珠放置在PVA薄膜上或嵌入PVA薄膜中，这构成了模型系统的形成。NanoIR 成像和光谱测量是在评估位于 PVA 薄膜上或下方的相同 PS 微珠产生的信号的背景下描述的。评估磁珠位置对nanoIR信号的影响。讨论了评估纳米红外图中磁珠空间足迹的方法，并考虑了几个参数的影响。

<table border="1" fo:keep-together.within-page="1" fo:keep-with-next.within-page="always">
	<tbody>
		<tr>
			<td>10|0 2200 Golden Taklon Round</td>
			<td>Zem</td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>5357-8NM Tweezers</td>
			<td>Pelco</td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Adhesive Tabs</td>
			<td>Ted Pella</td>
			<td>16079</td>
			<td></td>
		</tr>
		<tr>
			<td>AFM metal specimen disks</td>
			<td>Ted Pella</td>
			<td>16208</td>
			<td></td>
		</tr>
		<tr>
			<td>Binocular</td>
			<td>AmScope</td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Cantilever for nanoIR measurements</td>
			<td>AppNano</td>
			<td></td>
			<td>FORTGG</td>
		</tr>
		<tr>
			<td>Cell culture dishes</td>
			<td>Greiner bio-one GmbH</td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Desiccator</td>
			<td></td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Floating optical table</td>
			<td>Newport</td>
			<td>RS 4000</td>
			<td></td>
		</tr>
		<tr>
			<td>Hotplate</td>
			<td>VWR</td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Isopropanol&#160;</td>
			<td></td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Kimwipes</td>
			<td>KIMTECH</td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Magnetic stir bar</td>
			<td></td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Microparticles based on polystyrene size: 5 &#181;m</td>
			<td>SIGMA-ALDRICH</td>
			<td>79633</td>
			<td></td>
		</tr>
		<tr>
			<td>nanoIR2 microscope</td>
			<td>Bruker</td>
			<td></td>
			<td>Contact mode NanoIR2</td>
		</tr>
		<tr>
			<td>Nitrogen Tank</td>
			<td>Airgas</td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Petri dishes</td>
			<td>Greiner bio-one GmbH</td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Polyvinyl Alcohol</td>
			<td>SIGMA-ALDRICH</td>
			<td>363170</td>
			<td>this polymer was only 87%-89% hydrolyzed, which explains the presence of residual C=O at 1730 cm-1</td>
		</tr>
		<tr>
			<td>Quantum Cascade Laser</td>
			<td>Daylight Solutions</td>
			<td></td>
			<td>1550-1800 cm-1 range</td>
		</tr>
		<tr>
			<td>Silicon wafer</td>
			<td>MEMC St. Peters</td>
			<td>#901319343000</td>
			<td></td>
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		<tr>
			<td>Spin coater</td>
			<td>Oscilla</td>
			<td></td>
			<td></td>
		</tr>
	</tbody>
</table>

advances in nanoscale infrared spectroscopy to explore multiphase polymeric systems

多相聚合物系统包含局部域，其尺寸可以从几十纳米到几微米不等。它们的成分通常使用红外光谱法进行评估，红外光谱法提供了探测体积中所含各种材料的平均指纹。但是，这种方法没有提供有关材料中相位安排的任何细节。两种聚合物相之间的界面区域（通常在纳米级范围内）也难以进入。光热纳米级红外光谱通过原子力显微镜（AFM）的灵敏探针监测红外光激发的材料的局部响应。虽然该技术适用于研究小特征，例如原始金表面上的单个蛋白质，但三维多组分材料的表征更加难以捉摸。这是由于与AFM尖端探测的纳米级区域相比，发生光热膨胀的材料相对较大，由激光聚焦到样品上和聚合物成分的热特性定义。使用聚苯乙烯 （PS） 珠和聚乙烯醇 （PVA） 薄膜，我们评估了用于表面分析的光热纳米级红外光谱的空间足迹，作为 PS 在 PVA 薄膜中位置的函数。研究了特征位置对纳米级红外图像的影响，并获得了光谱。考虑到具有嵌入聚合物结构的复杂系统的表征，对光热纳米级红外光谱领域的未来进展提出了一些看法。

将PS（（C8H8）n）珠子沉积在干净的Si衬底（图1A）和PVA（（CH2CHOH）n）（图1B，C）上。由于磁珠在硅上的附着力较差，因此无法对该样品进行接触模式下的纳米红外成像。取而代之的是，使用nanoIR上样品的光学视图，镀金的AFM探针以接触模式接合在PS微珠的顶部，估计力约为100 nN（图2...

Watch this Scientific Journal Video about Advances in Nanoscale Infrared Spectroscopy to Explore Multiphase Polymeric Systems at JoVE.com

作者聚焦:探索多相聚合物系统的纳米级红外光谱进展  

该协议描述了原子力显微镜和纳米级红外光谱的应用，以评估光热纳米级红外光谱在三维多聚物样品表征中的性能。

纳米级红外光谱探索多相聚合物体系的进展

Multiphase polymeric systems encompass local domains with dimensions that can vary from a few tens of nanometers to several micrometers. Their composition ...

我们小组专注于推进纳米级功能成像和光谱学领域，以研究复杂系统，重点是纳米级红外光谱学。我们的研究旨在开发方法，使我们能够通过研究异质系统的纳米级特性来理解它们的行为。了解不同频率的驱动作用以提取有关样品的信息至关重要。由于这很复杂，因此开发可以使用物理仿真包进行建模的样本也很重要。纳米级红外光谱法确定测量的穿透深度并了解地下特征如何影响 AFM 针尖检测到的信号非常重要。该协议提出了一种简单的方法来创建一个模型系统，该系统能够量化纳米级红外光谱的穿透深度，以及JUUL加热对多相聚合物材料测量中涉及的样品响应的影响。我们的团队将继续专注于开发新的想法，以改进纳米级红外光谱学和其他纳米级功能工具，以小规模探索现实生活中的系统。

advances-nanoscale-infrared-spectroscopy-to-explore-multiphase

Research

JoVE Journal

Engineering

Advances in Nanoscale Infrared Spectroscopy to Explore Multiphase Polymeric Systems

734 次观看.  University of Central Florida. 我们小组专注于推进纳米级功能成像和光谱学领域，以研究复杂系统，重点是纳米级红外光谱学。我们的研究旨在开发方法，使我们能够通过研究异质系统的纳米级特性来理解它们的行为。了解不同频率的驱动作用以提取有关样品的信息至关重要。由于这很复杂，因此开发可以使用物理仿真包进行建模的样本也很重要。纳米级红外光谱法确定测量的穿透深度并了解地下?...

视频: 作者聚焦:探索多相聚合物系统的纳米级红外光谱进展  

Concurrent Quantitative Conductivity and Mechanical Properties Measurements of Organic Photovoltaic Materials using AFM

Organic photovoltaic (OPV) materials are inherently inhomogeneous at the nanometer scale. Nanoscale inhomogeneity of OPV materials affects performance of photovoltaic devices. Thus, understanding of spatial variations in composition as well as electrical properties of OPV materials is of paramount importance for moving PV technology forward.1,2 In this paper, we describe a protocol for quantitative measurements of electrical and mechanical properties of OPV materials with sub-100 nm resolution. Currently, materials properties measurements performed using commercially available AFM-based techniques (PeakForce, conductive AFM) generally provide only qualitative information. The values for resistance as well as Young's modulus measured using our method on the prototypical ITO/PEDOT:PSS/P3HT:PC61BM system correspond well with literature data. The P3HT:PC61BM blend separates onto PC61BM-rich and P3HT-rich domains. Mechanical properties of PC61BM-rich and P3HT-rich domains are different, which allows for domain attribution on the surface of the film. Importantly, combining mechanical and electrical data allows for correlation of the domain structure on the surface of the film with electrical properties variation measured through the thickness of the film.

Organic photovoltaic (OPV) materials are inherently inhomogeneous at the nanometer scale. Nanoscale inhomogeneity of OPV materials affects performance of photovoltaic devices. In this paper, we describe a protocol for quantitative measurements of electrical and mechanical properties of OPV materials with sub-100 nm resolution.

并行定量的导电性和力学性能测试的有机光伏材料利用原子力显微镜

Organic photovoltaic  (OPV) materials are inherently inhomogeneous at the nanometer scale. Nanoscale  inhomogeneity of OPV materials affects performance ...

科研

工程学

Proton Transfer and Protein Conformation Dynamics in Photosensitive Proteins by Time-resolved Step-scan Fourier-transform Infrared Spectroscopy

Monitoring the dynamics of protonation and protein backbone conformation changes during the function of a protein is an essential step towards understanding its mechanism. Protonation and conformational changes affect the vibration pattern of amino acid side chains and of the peptide bond, respectively, both of which can be probed by infrared (IR) difference spectroscopy. For proteins whose function can be repetitively and reproducibly triggered by light, it is possible to obtain infrared difference spectra with (sub)microsecond resolution over a broad spectral range using the step-scan Fourier transform infrared technique. With ~102-103 repetitions of the photoreaction, the minimum number to complete a scan at reasonable spectral resolution and bandwidth, the noise level in the absorption difference spectra can be as low as ~10-4, sufficient to follow the kinetics of protonation changes from a single amino acid. Lower noise levels can be accomplished by more data averaging and/or mathematical processing. The amount of protein required for optimal results is between 5-100 &#181;g, depending on the sampling technique used. Regarding additional requirements, the protein needs to be first concentrated in a low ionic strength buffer and then dried to form a film. The protein film is hydrated prior to the experiment, either with little droplets of water or under controlled atmospheric humidity. The attained hydration level (g of water / g of protein) is gauged from an IR absorption spectrum. To showcase the technique, we studied the photocycle of the light-driven proton-pump bacteriorhodopsin in its native purple membrane environment, and of the light-gated ion channel channelrhodopsin-2 solubilized in detergent.

Key steps of protein function, in particular backbone conformational changes and proton transfer reactions, often take place in the microsecond to millisecond time scale. These dynamical processes can be studied by time-resolved step-scan Fourier-transform infrared spectroscopy, in particular for proteins whose function is triggered by light.

质子转移和蛋白质构象动力学的光敏蛋白的时间分辨步进扫描傅立叶变换红外光谱

Monitoring the dynamics of protonation and protein backbone conformation changes during the function of a protein is an essential step towards ...

Thermal Measurement Techniques in Analytical Microfluidic Devices

Thermal measurement techniques have been used for many applications such as thermal characterization of materials and chemical reaction detection. Micromachining techniques allow reduction of the thermal mass of fabricated structures and introduce the possibility to perform high sensitivity thermal measurements in the micro-scale and nano-scale devices. Combining thermal measurement techniques with microfluidic devices allows performing different analytical measurements with low sample consumption and reduced measurement time by integrating the miniaturized system on a single chip. The procedures of thermal measurement techniques for particle detection, material characterization, and chemical detection are introduced in this paper.

Here, we present three protocols for thermal measurements in microfluidic devices.

在分析微流体装置的热测量技术

Thermal measurement techniques have been used for many applications such as thermal characterization of materials and chemical reaction detection. ...

Detection and Recovery of Palladium, Gold and Cobalt Metals from the Urban Mine Using Novel Sensors/Adsorbents Designated with Nanoscale Wagon-wheel-shaped Pores

Developing low-cost, efficient processes for recovering and recycling palladium, gold and cobalt metals from urban mine remains a significant challenge in industrialized countries. Here, the development of optical mesosensors/adsorbents (MSAs) for efficient recognition and selective recovery of Pd(II), Au(III), and Co(II) from urban mine was achieved. A simple, general method for preparing MSAs based on using high-order mesoporous monolithic scaffolds was described. Hierarchical cubic Ia3d wagon-wheel-shaped MSAs were fabricated by anchoring chelating agents (colorants) into three-dimensional pores and micrometric particle surfaces of the mesoporous monolithic scaffolds. Findings show, for the first time, evidence of controlled optical recognition of Pd(II), Au(III), and Co(II) ions and a highly selective system for recovery of Pd(II) ions (up to ~95%) in ores and industrial wastes. Furthermore, the controlled assessment processes described herein involve evaluation of intrinsic properties (e.g., visual signal change, long-term stability, adsorption efficiency, extraordinary sensitivity, selectivity, and reusability); thus, expensive, sophisticated instruments are not required. Results show evidence that MSAs will attract worldwide attention as a promising technological means of recovering and recycling palladium, gold and cobalt metals.

Because of the importance and extensive use of palladium, gold and cobalt metals in high-technology equipment, their recovery and recycling constitute an important industrial challenge. The metal recovery system described herein is a simple, low-cost means for the effective detection, removal, and recovery of these metals from the urban mine.

检测和钯的回收，从城市矿山黄金和钴金属使用标有纳米货车车轮形的孔隙新型传感器/吸附剂

Developing low-cost, efficient processes for recovering and recycling palladium, gold and cobalt metals from urban mine remains a significant challenge in ...

Resonance Raman Spectroscopy of Extreme Nanowires and Other 1D Systems

This paper briefly describes how nanowires with diameters corresponding to 1 to 5 atoms can be produced by melting a range of inorganic solids in the presence of carbon nanotubes. These nanowires are extreme in the sense that they are the limit of miniaturization of nanowires and their behavior is not always a simple extrapolation of the behavior of larger nanowires as their diameter decreases. The paper then describes the methods required to obtain Raman spectra from extreme nanowires and the fact that due to the van Hove singularities that 1D systems exhibit in their optical density of states, that determining the correct choice of photon excitation energy is critical. It describes the techniques required to determine the photon energy dependence of the resonances observed in Raman spectroscopy of 1D systems and in particular how to obtain measurements of Raman cross-sections with better than 8% noise and measure the variation in the resonance as a function of sample temperature. The paper describes the importance of ensuring that the Raman scattering is linearly proportional to the intensity of the laser excitation intensity. It also describes how to use the polarization dependence of the Raman scattering to separate Raman scattering of the encapsulated 1D systems from those of other extraneous components in any sample.

The paper describes a method for producing extreme nanowires by melt infiltration into carbon nanotubes and how 1D systems may be characterized and investigated using Resonance Raman Spectroscopy to determine vibrational and optical excitation energies.

至尊纳米线和其他维系统的共振拉曼光谱

This paper briefly describes how nanowires with diameters corresponding to 1 to 5 atoms can be produced by melting a range of inorganic solids in the ...

Free-form Light Actuators &#8212; Fabrication and Control of Actuation in Microscopic Scale

Liquid crystalline elastomers (LCEs) are smart materials capable of reversible shape-change in response to external stimuli, and have attracted researchers&#39; attention in many fields. Most of the studies focused on macroscopic LCE structures (films, fibers) and their miniaturization is still in its infancy. Recently developed lithography techniques, e.g., mask exposure and replica molding, only allow for creating 2D structures on LCE thin films. Direct laser writing (DLW) opens access to truly 3D fabrication in the microscopic scale. However, controlling the actuation topology and dynamics at the same length scale remains a challenge.
In this paper we report on a method to control the liquid crystal (LC) molecular alignment in the LCE microstructures of arbitrary three-dimensional shape. This was made possible by a combination of direct laser writing for both the LCE structures as well as for micrograting patterns inducing local LC alignment. Several types of grating patterns were used to introduce different LC alignments, which can be subsequently patterned into the LCE structures. This protocol allows one to obtain LCE microstructures with engineered alignments able to perform multiple opto-mechanical actuation, thus being capable of multiple functionalities. Applications can be foreseen in the fields of tunable photonics, micro-robotics, lab-on-chip technology and others.

Here, we fabricate 3D polymeric micro/nano structures in which both the shape and the molecular alignment can be engineered with nanometer scale accuracy by the use of direct laser writing. Light induced deformation of several types of liquid crystalline elastomer microstructures can be controlled in the microscopic scale.

自由形式的光驱动器 - 制作和开动控制在微观尺度

Liquid crystalline elastomers (LCEs) are smart materials capable of reversible shape-change in response to external stimuli, and have attracted ...

The Evolution of Silica Nanoparticle-polyester Coatings on Surfaces Exposed to Sunlight

Corrosion of metallic surfaces is prevalent in the environment and is of great concern in many areas, including the military, transport, aviation, building and food industries, amongst others. Polyester and coatings containing both polyester and silica nanoparticles (SiO2NPs) have been widely used to protect steel substrata from corrosion. In this study, we utilized X-ray photoelectron spectroscopy, attenuated total reflection infrared micro-spectroscopy, water contact angle measurements, optical profiling and atomic force microscopy to provide an insight into how exposure to sunlight can cause changes in the micro- and nanoscale integrity of the coatings. No significant change in surface micro-topography was detected using optical profilometry, however, statistically significant nanoscale changes to the surface were detected using atomic force microscopy. Analysis of the X-ray photoelectron spectroscopy and attenuated total reflection infrared micro-spectroscopy data revealed that degradation of the ester groups had occurred through exposure to ultraviolet light to form COO&#903;, -H2C&#903;, -O&#903;, -CO&#903; radicals. During the degradation process, CO and CO2 were also produced.

Two types of surfaces, polyester-coated steel and polyester coated with a layer of silica nanoparticles, were studied. Both surfaces were exposed to sunlight, which was found to cause substantial changes in the chemistry and nanoscale topography of the surface.

表面上的纳米硅聚酯涂料暴露在阳光下的演变

Corrosion of metallic surfaces is prevalent in the environment and is of great concern in many areas, including the military, transport, aviation, ...

High-speed Continuous-wave Stimulated Brillouin Scattering Spectrometer for Material Analysis

Recent years have witnessed a significant increase in the use of spontaneous Brillouin spectrometers for non-contact analysis of soft matter, such as aqueous solutions and biomaterials, with fast acquisition times. Here, we discuss the assembly and operation of a Brillouin spectrometer that uses stimulated Brillouin scattering (SBS) to measure stimulated Brillouin gain (SBG) spectra of water and lipid emulsion-based tissue-like samples in transmission mode with &lt;10 MHz spectral-resolution and &lt;35 MHz Brillouin-shift measurement precision at &lt;100 ms. The spectrometer consists of two nearly counter-propagating continuous-wave (CW) narrow-linewidth lasers at 780 nm whose frequency detuning is scanned through the material Brillouin shift. By using an ultra-narrowband hot rubidium-85 vapor notch filter and a phase-sensitive detector, the signal-to-noise-ratio of the SBG signal is significantly enhanced compared to that obtained with existing CW-SBS spectrometers. This improvement enables measurement of SBG spectra with up to 100-fold faster acquisition times, thereby facilitating high spectral-resolution and high-precision Brillouin analysis of soft materials at high speed.

We describe the construction of a rapid continuous-wave-stimulated-Brillouin-scattering (CW-SBS) spectrometer. The spectrometer employs single-frequency diode-lasers and an atomic vapor notch-filter to acquire transmission spectra of turbid/non-turbid samples with high spectral-resolution at speeds up to 100-fold faster than those of existing CW-SBS spectrometers. This improvement enables high-speed Brillouin material analysis.

用于材料分析的高速连续波受激布里渊散射光谱仪

Recent years have witnessed a significant increase in the use of spontaneous Brillouin spectrometers for non-contact analysis of soft matter, such as ...

A Novel Method for In Situ Electromechanical Characterization of Nanoscale Specimens

Electrically assisted deformation (EAD) is increasingly being used to improve the formability of metals during processes such as sheet metal rolling and forging. Adoption of this technique is proceeding despite disagreement concerning the underlying mechanism responsible for EAD. The experimental procedure described herein enables a more explicit study compared to previous EAD research by removing thermal effects, which are responsible for disagreement in interpreting previous EAD results. Furthermore, as the procedure described here enables EAD observation in situ and in real time in a transmission electron microscope (TEM), it is superior to existing post-mortem methods that observe EAD effects post-test. Test samples consist of a single crystal copper (SCC) foil having a free-standing tensile test section of nanoscale thickness, fabricated using a combination of laser and ion beam milling. The SCC is mounted to an etched silicon base that provides mechanical support and electrical isolation while serving as a heat sink. Using this geometry, even at high current density (~3,500 A/mm2), the test section experiences a negligible temperature increase (&#60;0.02 &#176;C), thus eliminating Joule heating effects. Monitoring material deformation and identifying the corresponding changes to microstructures, e.g. dislocations, are accomplished by acquiring and analyzing a series of TEM images. Our sample preparation and in situ experiment procedures are robust and versatile as they can be readily utilized to test materials with different microstructures, e.g., single and polycrystalline copper.

A Novel Method for In Situ Electromechanical Characterization of Nanoscale Specimens

Isolating electrical and thermal effects on electrically assisted deformation (EAD) is very difficult using macroscopic samples. Metallic sample micro- and nanostructures together with a custom test procedure have been developed to evaluate the impact of applied current on the formation without joule heating and evolution of dislocations on these samples.

一种新的方法<em&gt;原位</em&gt;纳米级样品的机电表征

Electrically assisted deformation (EAD) is increasingly being used to improve the formability of metals during processes such as sheet metal rolling and ...

O-cresol Concentration Online Measurement Based On Near Infrared Spectroscopy Via Partial Least Square Regression

Unlike macroscopic process variables, near-infrared spectroscopy provides process information at the molecular level and can significantly improve the prediction of the components in industrial processes. The ability to record spectra for solid and liquid samples without any pretreatment is advantageous and the method is widely used. However, the disadvantages of analyzing high-dimensional near-infrared spectral data include information redundancy and multicollinearity of the spectral data. Thus, we propose to use partial least squares regression method, which has traditionally been used to reduce the data dimensionality and eliminate the collinearity between the original features. We implement the method for predicting the o-cresol concentration during the production of polyphenylene ether. The proposed approach offers the following advantages over component regression prediction methods: 1) partial least squares regression solves the multicollinearity problem of the independent variables and effectively avoids overfitting, which occurs in a regression analysis due to the high correlation between the independent variables; 2) the use of the near-infrared spectra results in high accuracy because it is a non-destructive and non-polluting method to obtain information at microscopic and molecular scales.

The protocol describes a method of predicting o-cresol concentration during the production of polyphenylene ether using near-infrared spectroscopy and partial least squares regression. To describe the process more clearly and completely, an example of predicting the o-cresol concentration during the production of polyphenylene is used to clarify the steps.

O-cresol 浓度在线测量基于近红外光谱通过部分最小平方回归

Unlike macroscopic process variables, near-infrared spectroscopy provides process information at the molecular level and can significantly improve the ...