Name: microfluidic-based synthesis of covalent organic frameworks (cofs): a tool for continuous production of cof fibers and direct printing on a surface
Uploaded: 2017-07-10T11:30:00.000+00:00
Duration: 8 min 42 s
Description: Watch this Scientific Journal Video about Microfluidic-based Synthesis of Covalent Organic Frameworks COFs: A Tool for Continuous Production of COF Fibers and Direct Printing on a Surface at JoVE.com

作者通过项目号码承认瑞士国家科学基金会（SNF）的财务支持。 200021_160174。

主模具制造<ol><li>执行4英寸硅母模的光刻制造，如前面详细描述的19 ;本研究中使用的主模具使用相同的方案制造。 注意:微流控器件通常通过多步法制造。第一步是使用传统绘图软件设计微流体通道。然后，产生含有微流控网络的高分辨率薄膜光掩模，其特征精度为约5μm。接下来，通过标准光刻技术在4英寸硅晶片上制造母模。在目前的研究中，采用SU-8作为负型光致抗蚀剂来制造母模。在我们的设备中，SU-8结构的高度定义为50μm。最后，通过直接浇铸透明聚合物（通常是聚二甲基硅氧烷）来制造微流体装置羟基硅氧烷（PDMS）。 </li></ol> 2.单层微流体装置的制造注意:协议要求在70°C下进行烤箱操作。在开始制造方案之前，烘箱的温度应稳定在70℃。较低的温度可能导致粘结不良和非功能性的设备。 <ol><li>将制作的主模具放入装有真空泵的干燥器中。然后，将100μL氯代三甲基硅烷倒入玻璃小瓶中，并将其放入干燥器中。 注意:注意！氯代三甲基硅烷是一种腐蚀性，危险和有毒物质。因此，所有的处理步骤应在通风通风橱下进行，并且必须佩戴合适的护目镜，手套和实验室外套。 </li><li>关闭干燥器并置于真空下（本实验中为51毫巴）。等待至少1小时以确保蒸发的氯代三甲基胺的沉积在模具表面的硅烷。 1小时后，轻轻打开干燥器的空气阀将其平衡至大气压力并将其打开。 注意:注意！干燥器打开一旦氯三甲基硅烷蒸气泄漏出来;不要直接在干燥器上方呼吸，并且始终在通风柜中执行上述操作。 </li><li>手动取出硅胶模具，并关闭干燥器。将主模具存放在封闭的箱体（或层流罩内），以避免颗粒在其表面上沉积。 注意:所有进行的步骤必须在均匀空气速度下运行的层流罩下进行。 </li><li>在一次性杯中制备PDMS预聚物和固化剂（重量比为10:0.9）的混合物，并用塑料刮刀剧烈混合。作为指导，使用20g弹性体和1.8g固化剂来制造大约5mm厚的四个PDMS微流体装置。 </li><li>放置含有混合好的PD的杯子MS在干燥器中在真空下脱气并除去气泡。一旦PDMS脱气，打开干燥器并取出杯子。 注意:在本实验中，在51毫巴下大约需要30分钟。 </li><li>轻轻地将四个正方形框架（ 例如 ，内部尺寸为24 mm x 24 mm的聚四氟乙烯（PTFE）框架）放置在主模具上，以使每个框架在主模具上形成围绕单个图案化结构的壁。 </li><li>将脱气的PDMS倒入框架中，并将母模顶部倒入充满状态。将带有方形框架的母模置于70℃的烘箱中2小时。 </li><li> 2小时后，从烤箱中取出母模，将组件放冷至室温。 </li><li>通过将它们与主模具仔细分离并将PDMS芯片滑出正方形框架，手动剥离结构化PDMS板（或PDMS芯片）和方框。 </li><li>冲孔入口和出口孔使用1.5 mm活检穿孔机在设计中， 例如 ，在微流体通道结束时的位置。切割多余的PDMS，并使用胶带从结构化PDMS芯片表面清除任何碎屑。 </li><li>将PDMS芯片（开放通道朝上）以及玻璃盖玻片放入等离子体发生器的腔室并关闭腔室。 </li><li>将等离子体发生器置于真空下（1.4 mbar）;将等离子体发生器切换1分钟。 </li><li> 1分钟后，关闭等离子体发生器，通风室，取出处理过的PDMS芯片和玻璃盖玻片。将PDMS芯片（从结构化通道的一侧）和玻璃盖玻片结合在一起以封闭通道;此时制造单层微流体装置。 </li><li>最后，将粘合的微流体装置放置在70℃的烘箱中至少4小时，以增强PDMS和玻璃之间的粘合。 </li></ol>准备微流体装置和前体溶液的离子<ol><li>在乙酸中制备0.040 M BTCA溶液。 注意:注意！乙酸是一种危险的，腐蚀性和易燃的化合物，其蒸气对眼睛和呼吸系统极度刺激。因此，处理步骤必须在通风橱中进行。此外，使用者必须戴上保护性实验衣，护目镜和手套。 </li><li>制备0.040 M的TAPB溶液在乙酸中。 注意:本实验中使用的微流体装置有四个入口通道（ 图1B和图2 ）。 </li><li>将BTCA和TAPB溶液装入两个不同的注射器（5 mL注射器，此处装有3 mL溶液），将注射器放入并固定到注射泵上，并将其连接到制造的微流体芯片的两个中间入口（每个入口一个试剂），使用PTFE管（内径0.8 mm）。 </li><li>用纯的另外两个注射器装载乙酸（这里是5 mL注射器完全装满），将注射器放入并固定到注射器泵上，并使用相同类型的PTFE管将其连接到微流控芯片的两个入口。 </li><li>将足够长的PTFE管（在当前实验中，约15厘米）连接到微流体芯片的出口。使用计算机控制的注射泵来激励流体流动，如以下步骤所述。 </li></ol>连续合成MF-COF纤维<ol><li>使用注射泵每次以100μL/ min的流速引入两根乙酸溶液，鞘流位于试剂流的外侧（ 图2 ）。 </li><li>等待1分钟，通过两个中间入口（每个入口一个试剂）分别以50μL/ min的流速注入两种试剂（TAPB和BTCA）。等待1分钟，直到稳定的流量建立。 </li><li>观察黄色纤维微结构的形成先前通过傅立叶变换红外（FT-IR）光谱，元素分析和固态13 C CP-MAS-NMR 6表征为MF-COF的固体;在这些条件下，MF-COF的形成不是连续的。 </li><li>将TAPB和BTCA的流速提高到200μL/ min，并保持醋酸的两个鞘流速100μL/ min。现在等待1分钟直到流量稳定。观察黄色MF-COF纤维的高度浓缩悬浮液的形成，最终导致出口堵塞。 </li><li>由于芯片和出口管现在不起作用，请使用新的芯片，并根据步骤3.3-3.6进行实验准备。 </li><li>以100μL/ min的流速引入两根乙酸鞘，并等待1分钟。将TAPB和BTCA的流量分别设置为100μL/ min，观察连续的黄色MF-COF纤维的形成。 </li><li>将管子的出口放在含有醋的培养皿中酸酸。例如，将10mL乙酸放入玻璃培养皿（直径60mm）中。一旦合成的纤维离开位于微流体装置的出口处的管，将管移动到表面上以便于连续MF-COF纤维的排出。 </li></ol>直接打印2D和3D MF-COF结构注意:由于合成纤维可能不完全均匀，必须调整沉积速度以确保连续印刷。 <ol><li>按照第3节所述准备微流体装置，并以100μL/ min的流速注入所有四种溶液。 </li><li>等待1分钟，直到流稳定，合成的MF-COF纤维离开位于微流体装置出口处的管。在位于微流体装置出口处的管的出口旁边准备一个干净的基材，用于直接印刷MF-COF纤维。 注意:在我们的调查中，24毫米所有印刷实验都采用x 76毫米玻璃盖玻片。 </li><li>将管连接到微流体装置的出口，使其端部比玻璃盖玻片高出几毫米。缓慢地将管子移动到玻璃盖玻片上，以方便MF-COF纤维的排出并避免聚集。 </li><li>一旦流动稳定，缓慢地将位于微流体装置出口处的管子从玻璃盖玻片大约2-3厘米处提起，以观察独立且稳定的MF-COF纤维。 </li><li>要继续打印，请将管道的出口朝玻璃盖玻片移回，并手动将管子移动到表面上，以绘制所需的2D或3D MF-COF结构。 </li></ol>

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作者没有什么可以披露的。

这里报道的基于微流体的合成方法提供了一种用于在表面上直接印刷COF材料的新颖且简单的方法。使用单层微流体装置进行合成，该装置包括与玻璃盖玻片接合的微流体PDMS芯片。微流体装置的制造可以通过PDMS相对于硅母模的常规铸造并随后将PDMS与压印的微通道对接在玻璃盖玻片上来实现。 为了成功组装微流体装置，重要的是在洁净室环境中制造母模以避免在光刻期间的污?...

共价有机骨架（COFs）是一类已知的多孔和结晶材料，其中有机结构单元通过共价键1,2,3,4,5牢固地保持在一起。 COF通常按照超分子化学原理进行组装，其中组成的分子结构单元选择性地反应以限定最终和预定的多孔组件。这种方法允许合成具有受控和有序结构的材料（ 例如 ，具有限定的孔尺寸）和组合物3,6,7,8 。与其他多孔材料相比，COF是独特的，因为它们由轻元素（C，H，B，N和O）组成，并具有可调谐孔<html>精神1，5 。受到这些独特和内在特征的启发，COF已经被评估为在化学分离中的潜在应用9 ，气体储存10和催化11 ，传感器12 ，光电子13 ，清洁能源技术14和电化学能量装置15 。 迄今为止，用于制备COF材料的绝大多数方法是基于溶剂热自缩合和共缩合反应，其中以高温和高压为标准。虽然COF是热稳定的，但它们通常受到有限的加工性能的影响， 即 COF通常是不溶性和不可加工的结晶粉末，这显着地限制了它们在潜在和实际应用范围内的使用ss ="xref"&gt; 2，6，8，16，17。尽管COF合成方面取得了显着的进展，但是在该领域的主要挑战是开发一种能够在适当反应条件（ 如温度和压力）下制备COF的方法，从而可以促进其在表面上的加工性能。 最近研究表明，Shiff碱化学可用于在室温下合成基于亚胺的COF。由于1,3,5-三（4-氨基苯基）苯（TAPB）和1,3,5-苯三甲醛（BTCA） 17 （ 图 ）的快速有效反应，形成了命名为RT-COF-1的COF 1A ）。通过使用平版印刷法在刚性和柔性表面上直接印刷RT-COF-1的微米和亚微米图案来证明该合成方法的功效，喷墨打印技术。最近，利用微流体，我们已经证明了用于连续合成相同亚胺基COF（以下称为MF-COF 6）的纤维的有效方法。与用于生成COF 18的其他报道的合成方法不同，这种基于微流体的合成方法使得能够在几秒钟内在环境温度和压力下快速合成MF-COF纤维。此外，由于合成的MF-COF纤维的机械稳定性，我们已经证明了这种基于微流体的方法如何能够在表面上直接印刷2D和3D结构。在这里，我们证明该方法可用于在具有不同化学和物理性质的各种表面上绘制COF结构。我们认为，这种新方法为不同方向和各种表面上的COF的良好控制图案化和直接印刷打开了新的途径。

<table><tbody><tr><td>High resolution film masks</td><td>Microlitho, UK</td><td>-</td><td>Features down to 5um</td></tr><tr><td>Silicon wafers</td><td>Silicon Materials Inc., Germany</td><td>4&quot; Silicon Wafers</td><td>Front surface: polished, back surface: etched</td></tr><tr><td>Silicone Elastomer KIT (PDMS)</td><td>Dow Corning, USA</td><td>Sylgard 184</td><td>-</td></tr><tr><td>Chlorotrimethylsilane</td><td>Sigma-Aldrich, Switzerland</td><td>386529</td><td>&amp;ge;97%, CAUTION: Handle it only under fume hood.</td></tr><tr><td>Biopsy puncher</td><td>Miltex GmBH, Germany</td><td>33-31A-P/25</td><td>1.5 mm</td></tr><tr><td>Glass coverslip</td><td>Menzel-Glaser, Germany</td><td>BB024040SC</td><td>24 mm &amp;times; 40 mm, #5</td></tr><tr><td>Plasma generator instrument</td><td>Diener</td><td>Zepto B</td><td>Frequency: 40 kHz and plasma generator power: 0-30 W</td></tr><tr><td>PTFE tubing</td><td>PKM SA, Switzerland</td><td>AWG-TFS-XXX</td><td>AWG 20TFS, roll of 100 m</td></tr><tr><td>neMESYS Syringe Pumps</td><td>Cetoni GmbH, Germany</td><td>Low Pressure (290N)</td><td>-</td></tr><tr><td>Disposable Cup</td><td>Semadeni, Switzerland</td><td>8323</td><td>PS, 200 ml</td></tr><tr><td>Plastic Spatula</td><td>Semadeni, Switzerland</td><td>3340</td><td>L &amp;times; W : 135 mm x 14 mm</td></tr><tr><td>Disposable Scalpels</td><td>B. Braun, Switzerland</td><td>233-5320</td><td>Nr. 20</td></tr><tr><td>Disposable Syringes</td><td>VWR, Switzerland</td><td>613-3951</td><td>5 ml, Discardit II</td></tr><tr><td>Acetic Acid</td><td>Sigma-Aldrich, Switzerland</td><td>695092-500</td><td>&gt;=99.7%, CAUTION: Handle it only under fume hood.</td></tr><tr><td>1,3,5-benzenetricarbaldehyde</td><td>Aldrich-Fine Chemicals</td><td>753491</td><td>97%</td></tr><tr><td>1,3,5-Tris(4-aminophenyl)benzene</td><td>Tokyo Chemical Industry</td><td>T2728-5G</td><td>&gt;93.0%</td></tr></tbody></table>

microfluidic-based synthesis of covalent organic frameworks (cofs): a tool for continuous production of cof fibers and direct printing on a surface

共价有机骨架（COFs）是一类多孔共价材料，经常被合成为不可加工的结晶粉末。 2005年第一次报告了COF，其重点是建立新的合成路线进行准备。迄今为止，用于COF合成的大多数可用的合成方法是基于在溶剂热条件下的体积混合。因此，越来越多的兴趣开发COF合成的系统方案，提供对反应条件的精细控制，并提高表面上的COF加工性，这对于在实际应用中的应用至关重要。在本文中，我们提出了一种新型的基于微流体的COF合成方法，其中两个构成结构单元1,3,5-苯三甲醛（BTCA）和1,3,5-三（4-氨基苯基）苯（TAPB）之间的反应，在受控扩散条件下和室温下进行。使用这种方法会产生海绵样的哭泣COF材料的高分子纤维，以下称为MF-COF。 MF-COF的机械性能和该方法的动态特性允许连续生产MF-COF纤维并直接印刷在表面上。一般方法开辟了新的潜在应用，需要在柔性或刚性表面上高级打印2D或3D COF结构。

在我们的研究中使用的微流体装置是使用传统的PDMS复制模制20制造的，并且包括合并到主微通道中的四个微流体入口通道。最终的微流体装置由结构化PDMS层和用于封闭印迹微通道的玻璃盖玻片组成， 如图1B所示。 <img alt="图1" class="xfigimg" src="/files/ftp_upload/56020/56020fig1.jpg" /> 图1...

Watch this Scientific Journal Video about Microfluidic-based Synthesis of Covalent Organic Frameworks COFs: A Tool for Continuous Production of COF Fibers and Direct Printing on a Surface at JoVE.com

Microfluidic-based Synthesis of Covalent Organic Frameworks COFs: A Tool for Continuous Production of COF Fibers and Direct Printing on a Surface

我们提出一种新型的基于微流体的合成共价有机骨架（COFs）的方法。我们展示了如何使用这种方法来生产连续的COF纤维，以及表面上的2D或3D COF结构。

基于微流体的共价有机骨架（COFs）的合成:用于连续生产COF纤维和直接印刷在表面上的工具

Covalent Organic Frameworks (COFs) are a class of porous covalent materials which are frequently synthesized as unprocessable crystalline powders. The ...

microfluidic-based-synthesis-covalent-organic-frameworks-cofs-tool

Universidad San Sebastian

Research

JoVE Journal

Chemistry

Microfluidic-based Synthesis of Covalent Organic Frameworks (COFs): A Tool for Continuous Production of COF Fibers and Direct Printing on a Surface

13.3K 次观看.  ETH Zurich. 我们提出一种新型的基于微流体的合成共价有机骨架（COFs）的方法。我们展示了如何使用这种方法来生产连续的COF纤维，以及表面上的2D或3D COF结构。 

视频: Microfluidic-based Synthesis of Covalent Organic Frameworks COFs: A Tool for Continuous Production of COF Fibers and Direct Printing on a Surface

Fabrication, Densification, and Replica Molding of 3D Carbon Nanotube Microstructures

The introduction of new materials and processes to microfabrication has, in large part, enabled many important advances in microsystems, lab-on-a-chip devices, and their applications. In particular, capabilities for cost-effective fabrication of polymer microstructures were transformed by the advent of soft lithography and other micromolding techniques 1, 2, and this led a revolution in applications of microfabrication to biomedical engineering and biology. Nevertheless, it remains challenging to fabricate microstructures with well-defined nanoscale surface textures, and to fabricate arbitrary 3D shapes at the micro-scale. Robustness of master molds and maintenance of shape integrity is especially important to achieve high fidelity replication of complex structures and preserving their nanoscale surface texture. The combination of hierarchical textures, and heterogeneous shapes, is a profound challenge to existing microfabrication methods that largely rely upon top-down etching using fixed mask templates. On the other hand, the bottom-up synthesis of nanostructures such as nanotubes and nanowires can offer new capabilities to microfabrication, in particular by taking advantage of the collective self-organization of nanostructures, and local control of their growth behavior with respect to microfabricated patterns. 
Our goal is to introduce vertically aligned carbon nanotubes (CNTs), which we refer to as CNT "forests", as a new microfabrication material. We present details of a suite of related methods recently developed by our group: fabrication of CNT forest microstructures by thermal CVD from lithographically patterned catalyst thin films; self-directed elastocapillary densification of CNT microstructures; and replica molding of polymer microstructures using CNT composite master molds. In particular, our work shows that self-directed capillary densification ("capillary forming"), which is performed by condensation of a solvent onto the substrate with CNT microstructures, significantly increases the packing density of CNTs. This process enables directed transformation of vertical CNT microstructures into straight, inclined, and twisted shapes, which have robust mechanical properties exceeding those of typical microfabrication polymers. This in turn enables formation of nanocomposite CNT master molds by capillary-driven infiltration of polymers. The replica structures exhibit the anisotropic nanoscale texture of the aligned CNTs, and can have walls with sub-micron thickness and aspect ratios exceeding 50:1. Integration of CNT microstructures in fabrication offers further opportunity to exploit the electrical and thermal properties of CNTs, and diverse capabilities for chemical and biochemical functionalization 3.

We present methods for fabrication of patterned microstructures of vertically aligned carbon nanotubes (CNTs), and their use as master molds for production of polymer microstructures with organized nanoscale surface texture. The CNT forests are densified by condensation of solvent onto the substrate, which significantly increases their packing density and enables self-directed formation of 3D shapes.

制备，致密，副本三维碳纳米管微结构成型

The introduction of new materials and processes to microfabrication has, in large part, enabled many important advances in microsystems, lab-on-a-chip ...

科研

工程学

Manufacturing of Three-dimensionally Microstructured Nanocomposites through Microfluidic Infiltration

Microstructured composite beams reinforced with complex three-dimensionally (3D) patterned nanocomposite microfilaments are fabricated via nanocomposite in&#64257;ltration of 3D interconnected microfluidic networks. The manufacturing of the reinforced beams begins with the fabrication of microfluidic networks, which involves layer-by-layer deposition of fugitive ink filaments using a dispensing robot, filling the empty space between filaments using a low viscosity resin, curing the resin and finally removing the ink.&#160;Self-supported 3D structures with other geometries and many layers (e.g.&#160;a few hundreds layers) could be built using this method. The resulting tubular micro&#64258;uidic networks are then infiltrated with thermosetting nanocomposite suspensions containing nanofillers (e.g.&#160;single-walled carbon nanotubes), and subsequently cured. The infiltration is done by applying a pressure gradient between two ends of the empty network (either by applying a vacuum or vacuum-assisted microinjection). Prior to the infiltration, the nanocomposite suspensions are prepared by dispersing nanofillers into polymer matrices using ultrasonication and three-roll mixing methods. The nanocomposites (i.e.&#160;materials infiltrated) are then solidified under UV exposure/heat cure, resulting in a 3D-reinforced composite structure. The technique presented here enables the design of functional nanocomposite macroscopic products for microengineering applications such as actuators and sensors.

Three-dimensional (3D) microstructured composite beams are fabricated through the directed and localized infiltration of nanocomposites into 3D porous microfluidic networks. The flexibility of this manufacturing method enables the utilization of different thermosetting materials and nanofillers in order to achieve a variety of functional 3D reinforced nanocomposite macroscopic products.

通过微流体渗透制备三维微结构纳米复合材料的制造

Microstructured composite beams reinforced with complex three-dimensionally (3D) patterned nanocomposite microfilaments are fabricated via nanocomposite ...

化学

Synthesis and Characterization of Functionalized Metal-organic Frameworks

Metal-organic frameworks have attracted extraordinary amounts of research attention, as they are attractive candidates for numerous industrial and technological applications. Their signature property is their ultrahigh porosity, which however imparts a series of challenges when it comes to both constructing them and working with them. Securing desired MOF chemical and physical functionality by linker/node assembly into a highly porous framework of choice can pose difficulties, as less porous and more thermodynamically stable congeners (e.g., other crystalline polymorphs, catenated analogues) are often preferentially obtained by conventional synthesis methods. Once the desired product is obtained, its characterization often requires specialized techniques that address complications potentially arising from, for example, guest-molecule loss or preferential orientation of microcrystallites. Finally, accessing the large voids inside the MOFs for use in applications that involve gases can be problematic, as frameworks may be subject to collapse during removal of solvent molecules (remnants of solvothermal synthesis). In this paper, we describe synthesis and characterization methods routinely utilized in our lab either to solve or circumvent these issues. The methods include solvent-assisted linker exchange, powder X-ray diffraction in capillaries, and materials activation (cavity evacuation) by supercritical CO2 drying. Finally, we provide a protocol for determining a suitable pressure region for applying the Brunauer-Emmett-Teller analysis to nitrogen isotherms, so as to estimate surface area of MOFs with good accuracy.

Synthesis, activation, and characterization of intentionally designed metal-organic framework materials is challenging, especially when building blocks are incompatible or unwanted polymorphs are thermodynamically favored over desired forms. We describe how applications of solvent-assisted linker exchange, powder X-ray diffraction in capillaries and activation via supercritical CO2 drying, can address some of these challenges.

功能化的合成与表征金属 - 有机骨架

Metal-organic frameworks have attracted extraordinary amounts of research attention, as they are attractive candidates for numerous industrial and ...

Prescribed 3-D Direct Writing of Suspended Micron/Sub-micron Scale Fiber Structures via a Robotic Dispensing System

A 3-axis dispensing system is utilized to control the initiating and terminating fiber positions and trajectory via the dispensing software. The polymer fiber length and orientation is defined by the spatial positioning of the dispensing system 3-axis stages. The fiber diameter is defined by the prescribed dispense time of the dispensing system valve, the feed rate (the speed at which the stage traverses from an initiating to a terminating position), the gauge diameter of the dispensing tip, the viscosity and surface tension of the polymer solution, and the programmed drawing length. The stage feed rate affects the polymer solution&#8217;s evaporation rate and capillary breakup of the filaments. The dispensing system consists of a pneumatic valve controller, a droplet-dispensing valve and a dispensing tip. Characterization of the direct write process to determine the optimum combination of factors leads to repeatedly acquiring the desired range of fiber diameters. The advantage of this robotic dispensing system is the ease of obtaining a precise range of micron/sub-micron fibers onto a desired, programmed location via automated process control. Here, the discussed self-assembled micron/sub-micron scale 3D structures have been employed to fabricate suspended structures to create micron/sub-micron fluidic devices and bioengineered scaffolds.

Here, we present a protocol to fabricate freely-suspended, micron/sub-micron scale polymer fibers and &#8220;web-like&#8221; structures generated via automated direct writing procedure by means of a 3-axis dispensing system.

暂停规定微米/亚微米尺度的纤维结构的3-D直写经全自动点胶系统

A 3-axis dispensing system is utilized to control the initiating and terminating fiber positions and trajectory via the dispensing software. The polymer ...

Microfluidic Pneumatic Cages: A Novel Approach for In-chip Crystal Trapping, Manipulation and Controlled Chemical Treatment

The precise localization and controlled chemical treatment of structures on a surface are significant challenges for common laboratory technologies. Herein, we introduce a microfluidic-based technology, employing a double-layer microfluidic device, which can trap and localize in situ and ex situ synthesized structures on microfluidic channel surfaces. Crucially, we show how such a device can be used to conduct controlled chemical reactions onto on-chip trapped structures and we demonstrate how the synthetic pathway of a crystalline molecular material and its positioning inside a microfluidic channel can be precisely modified with this technology. This approach provides new opportunities for the controlled assembly of structures on surface and for their subsequent treatment.

Herein, we describe the fabrication and operation of a double-layer microfluidic system made of polydimethylsiloxane (PDMS). We demonstrate the potential of this device for trapping, directing the coordination pathway of a crystalline molecular material and controlling chemical reactions onto on-chip trapped structures.

微流控气动笼:在芯片水晶捕获，处理的新方法和控制化学处理

The precise localization and controlled chemical treatment of structures on a surface are significant challenges for common laboratory technologies. ...

Millifluidics for Chemical Synthesis and Time-resolved Mechanistic Studies

Procedures utilizing millifluidic devices for chemical synthesis and time-resolved mechanistic studies are described by taking three examples. In the first, synthesis of ultra-small copper nanoclusters is described. The second example provides their utility for investigating time resolved kinetics of chemical reactions by analyzing gold nanoparticle formation using in situ X-ray absorption spectroscopy. The final example demonstrates continuous flow catalysis of reactions inside millifluidic channel coated with nanostructured catalyst.

Millifluidic devices are utilized for controlled synthesis of nanomaterials, time-resolved analysis of reaction mechanisms and continuous flow catalysis.

Millifluidics的化学合成和时间分辨机理研究

Procedures utilizing millifluidic devices for chemical synthesis and time-resolved mechanistic studies are described by taking three examples. In the ...

生物工程

Microfluidic Fabrication of Polymeric and Biohybrid Fibers with Predesigned Size and Shape

A &#8220;sheath&#8221; fluid passing through a microfluidic channel at low Reynolds number can be directed around another &#8220;core&#8221; stream and used to dictate the shape as well as the diameter of a core stream.&#160;Grooves in the top and bottom of a microfluidic channel were designed to direct the sheath fluid and shape the core fluid.&#160;By matching the viscosity and hydrophilicity of the sheath and core fluids, the interfacial effects are minimized and complex fluid shapes can be formed.&#160;Controlling the relative flow rates of the sheath and core fluids determines the cross-sectional area of the core fluid.&#160;Fibers have been produced with sizes ranging from 300 nm to ~1 mm, and fiber cross-sections can be round, flat, square, or complex as in the case with double anchor fibers. Polymerization of the core fluid downstream from the shaping region solidifies the fibers.&#160;Photoinitiated click chemistries are well suited for rapid polymerization of the core fluid by irradiation with ultraviolet light.&#160;Fibers with a wide variety of shapes have been produced from a list of polymers including liquid crystals, poly(methylmethacrylate), thiol-ene and thiol-yne resins, polyethylene glycol, and hydrogel derivatives. Minimal shear during the shaping process and mild polymerization conditions also makes the fabrication process well suited for encapsulation of cells and other biological components.

Two adjacent fluids passing through a grooved microfluidic channel can be directed to form a sheath around a prepolymer core; thereby&#160;determining both shape and cross-section. Photoinitiated polymerization, such as thiol click chemistry, is well suited for rapidly solidifying the core fluid into a microfiber with predetermined size and shape.

预设计尺寸和形状的聚合物纤维和生物贿赂纤维的微流体制造

A &#8220;sheath&#8221; fluid passing through a microfluidic channel at low Reynolds number can be directed around another &#8220;core&#8221; stream and ...

Solvothermal Synthesis of MIL-96 and UiO-66-NH2 on Atomic Layer Deposited Metal Oxide Coatings on Fiber Mats

Metal-organic frameworks (MOFs), which contain reactive metal clusters and organic ligands allowing for large porosities and surface areas, have proven effective in gas adsorption, separations, and catalysis. MOFs are most commonly synthesized as bulk powder, requiring additional processes to adhere them to functional devices and fabrics that risk decreasing the powder porosity and adsorption capacity. Here, we demonstrate a method of first coating fabrics with metal oxide films using atomic layer deposition (ALD). This process creates conformal films of controllable thickness on each fiber, while providing a more reactive surface for MOF nucleation. By submerging the ALD coated fabric in solution during solvothermal MOF synthesis, the MOFs create a conformal, well-adhered coating on the fibers, resulting in a MOF-functionalized fabric, without additional adhesion materials that may block MOF pores and functional sites. Here we demonstrate two solvothermal synthesis methods. First, we form a MIL-96(Al) layer on polypropylene fibers using synthetic conditions that convert the metal oxide to MOF. Using initial inorganic films of varying thicknesses, diffusion of the organic linker into the inorganic allows us to control the extent of MOF loading on the fabric. Second, we perform a solvothermal synthesis of UiO-66-NH2 in which the MOF nucleates on the conformal metal oxide coating on polyamide-6 (PA-6) fibers, thereby producing a uniform and conformal thin film of MOF on the fabric. The resulting materials can be directly incorporated into filter devices or protective clothing and eliminate the maladroit qualities of loose powder.

Solvothermal Synthesis of MIL-96 and UiO-66-NH2 on Atomic Layer Deposited Metal Oxide Coatings on Fiber Mats

Metal-organic frameworks are effective in gas storage and heterogeneous catalysis, but typical synthesis methods result in loose powders that are difficult to incorporate into smart materials. We demonstrate a method of first coating fabrics with ALD metal oxides, resulting in conformal films of MOF on the fabrics during solvothermal synthesis.

溶剂热合成 MIL-96 和 UiO-66-NH2在纤维垫上原子层沉积金属氧化物涂层上的合成

Metal-organic frameworks (MOFs), which contain reactive metal clusters and organic ligands allowing for large porosities and surface areas, have proven ...

Electrophoretic Crystallization of Ultrathin High-performance Metal-organic Framework Membranes

We report the synthesis of thin, highly intergrown, polycrystalline metal-organic framework (MOF) membranes on a wide range of unmodified porous and non-porous supports (polymer, ceramic, metal, carbon, and graphene). We developed a novel crystallization technique, which is termed the ENACT approach: the electrophoretic nuclei assembly for the crystallization of highly intergrown thin films (ENACT). This approach allows for a high density of heterogeneous nucleation of MOFs on a chosen substrate via the electrophoretic deposition (EPD) directly from the precursor sol. The growth of well-packed MOF nuclei leads to a highly intergrown polycrystalline MOF film. We show that this simple approach can be used for the synthesis of thin, intergrown zeolite imidazole framework (ZIF)-7 and ZIF-8 films. The resulting 500 nm-thick ZIF-8 membranes show a considerably high H2 permeance (8.3 x 10-6 mol m-2 s-1 Pa-1) and ideal gas selectivities (7.3 for H2/CO2, 15.5 for H2/N2, 16.2 for H2/CH4, and 2655 for H2/C3H8). An attractive performance for C3H6/C3H8 separation is also achieved (a C3H6 permeance of 9.9 x 10-8 mol m-2 s-1 Pa-1 and a C3H6/C3H8 ideal selectivity of 31.6 at 25 &#176;C). Overall, the ENACT process, owing to its simplicity, can be extended to synthesize intergrown thin films of a wide range of nanoporous crystalline materials.

A simple, reproducible, and versatile approach for the synthesis of intergrown, polycrystalline metal-organic framework membranes on a wide range of unmodified porous and non-porous supports is presented.

超薄高性能金属-有机骨架膜的电泳结晶

We report the synthesis of thin, highly intergrown, polycrystalline metal-organic framework (MOF) membranes on a wide range of unmodified porous and ...

Synthesis of Single-Crystalline Core-Shell Metal-Organic Frameworks

Because of their designability and unprecedented synergistic effects, core-shell metal-organic frameworks (MOFs) have been actively examined recently. However, the synthesis of single-crystalline core-shell MOFs is very challenging, and thus a limited number of examples have been reported. Here, we suggest a method of synthesizing single-crystalline HKUST-1@MOF-5 core-shells, which is HKUST-1 at the center of MOF-5. Through the computational algorithm, this pair of MOFs was predicted to have the matched lattice parameters and chemical connection points at the interface. To construct the core-shell structure, we prepared the octahedral- and cubic-shaped HKUST-1 crystals as a core MOF, in which the (111) and (001) facets were mainly exposed, respectively. Via the sequential reaction, the MOF-5 shell was well-grown on the exposed surface, showing a seamless connect interface, which resulted in the successful synthesis of single-crystalline HKUST-1@MOF-5. Their pure phase formation was proved by optical microscopic images and powder X-ray diffraction (PXRD) patterns. This method presents the potential of and insights into the single-crystalline core-shell synthesis with different kinds of MOFs.

Here, we demonstrate a protocol for the two-step synthesis of single-crystalline core-shells using a non-isostructural metal-organic framework (MOF) pair, HKUST-1 and MOF-5, which have well-matched crystal lattices.

单晶核壳金属有机骨架的合成

Because of their designability and unprecedented synergistic effects, core-shell metal-organic frameworks (MOFs) have been actively examined recently. ...