这项研究得到了院气候变化研究中心的支持 (格兰特 No。N11160012), 由科学、ICT 和未来规划部资助的韩国国家研究基金会领导的国外研究院招聘项目 (赠款 No. 2011-0030065), 主要的人力资源培训计划通过由科学、ICT 和未来规划部资助的韩国国家研究基金会 (NRF) 的区域新产业 (批准号:NRF-2016H1D5A1910603)。他们的支持得到了极大的赞赏。

1. 材料准备 <ol> <li> 复合材料的制备 注: 警告, 请在使用前查阅所有相关的材料安全数据表 (MSDS)。这些方法中使用的几种化学物质可能是有毒和致癌的。纳米材料与它们的散装相比可能有额外的危害。在进行试验时, 请使用所有适当的安全做法, 包括使用工程控制 (油烟罩、手套箱) 和个人防护用品 (安全眼镜、手套、实验室大衣、全长长裤、脚趾鞋). 
	注: 根据应用的不同, 增强纤维的类型可以是以下一种或多种: 单向纤维、梭织织物、无纺毡、切碎纤维。
	<ol> <li> 单向光纤类型 <ol> <li> 使用上复合材料 (预浸料), 因为它是最方便使用的. </li>
			<li> 将预浸料堆叠在包含0和 #176; 以及90和 #176 的堆叠序列中, 以避免分裂。例如, 堆叠到 [0 3 /90 3 ] s 。
		</ol> </li> <li> 梭织织物类型 <ol> <li> 准备编织的碳织物和膜型环氧树脂。如果使用预浸料, 请跳过步骤1.1.2.1 到 1.1.2.6. </li>
			<li> 用99.5% 丙酮或另一种溶剂清洗织物脱脂。清洗后要小心处理, 避免污染。将织物放在干净的表面或无绒的擦拭上. </li>
			<li> 在室温条件下干燥10分钟, 去除溶剂. </li>
			<li> 剥离环氧树脂的备份膜, 并将1层的薄膜型环氧树脂连接到碳织物1层. </li>
			<li> 将环氧连接的碳布放在预热70和 #176 的热板上; pre-impregnation 十年代的 C. </li>
			<li> 将准备好的预浸料在环境条件下冷却10分钟, 剥离其他备份胶片. </li>
			<li> 堆叠具有所需堆叠顺序的结构; 例如, 堆叠到 [0] 3 . </li>
		</ol> </li> <li> 无纺毡 <ol> <li> 准备无纺毡。
			<li> 用99.5% 丙酮或另一种溶剂清洁毛毡以进行脱脂。清洗后要小心, 避免污染。将毛毡放在干净的表面或无绒的擦拭上. </li>
			<li> 剥离环氧树脂的备份膜, 并将3层膜型环氧树脂连接到每一侧的1股碳毡上. </li>
			<li> 将环氧附着的碳毡放在预热70和 #176 的热板上; C 为 pre-impregnation 的十年代. </li>
			<li> 将准备好的预浸料在环境条件下冷却10分钟, 剥离其他备份胶片. </li>
		</ol> </li> </ol> </li> <li> 准备软层 注: 对于软层, 含氟聚合物如聚四氟乙烯 (PTFE) 或氟化乙烯丙烯 (FEP), 聚烯烃如聚乙烯或聚丙烯, 或合成橡胶, 如硅橡胶或氟可以使用。该方案采用了 FEP 膜, 其屈服强度大大超过120和 #176; C. 25 和 #181; m 厚 FEP 适用于单向纤维和无纺毡复合材料, 而厚的100和 #181; m 厚 FEP 适合于机织面料类型复合 10 。
	<ol> <li> 清除99.5% 丙酮的软层。小心处理, 避免皱纹和针孔. </li>
		<li> 用无绒抹布擦拭软层上的丙酮。确保软层上没有污染物, 因为在固化过程中它会被转移到复合材料中。始终保持软层远离灰尘和小颗粒, 因为这些可能不仅损害了复合材料, 而且还压缩模具. </li>
	</ol> </li> </ol> 2。复合制造 <ol> 压缩模具的安装 <ol> <li> 准备一个大小为120毫米和 #215 的空腔的压缩模具; 120 mm </li>
		<li> 将模具释放到压缩模具。只需粘贴或喷雾模具释放到模具, 并擦拭无绒抹布, 直到只有薄薄的一层的模具释放保持. </li>
		<li> 将准备好的复合板切割为118毫米和 #215 的尺寸; 118 mm </li>
		<li> 放置1层25和 #181; m 厚 FEP 膜在下部模具上. </li>
		<li> 将复合层压板放在 FEP 膜上, 并在层板上放置另一 FEP 膜. </li>
		<li> 拼合软层并去除在软层和复合层压板之间的气泡. </li>
		<li> 关闭模压成型模具. </li>
	</ol> </li> <li> 压缩成型 <ol> <li> 将热烫机加热到150和 #176; C. 
		注: 模具内的试样温度为140和 #176; C 在这种情况下。如果软层采用弹性体或聚烯烃, 也可以使用较低的温度。考虑复合材料的固化温度和软层软化温度, 以确定固化温度. </li>
		<li> 将模具放置在热压机中. </li>
		<li> 使用热压机施加压力; 固化时间和压力取决于复合类型。
		<ol> <li> 对于单向纤维复合材料, 在30分钟内施加20兆帕斯卡的恒定压力; 不需要其他进程. </li>
			<li> 对于梭织织物类型的复合, 应用20兆帕斯卡。4分钟和8分钟后, 将施加的压力释放到零, 并立即再次应用20兆帕斯卡. 
			注: 这个过程被称为清除, 其目的是去除过量的树脂和被诱捕的气泡。根据复合材料的大小, 清除步骤的数量可能会增加;尺寸复合材料需要更多的清洗。
			<ol> <li> 然而, 在树脂的黏度开始增加之后, 不要清除。治疗总共30分钟. </li>
			</ol> </li> <li> 无纺毡型复合物, 适用3兆帕斯卡30分钟. 当心压力过冲, 这将导致最终产品的空隙和缺陷。慢慢增加压力, 避免压力过大. </li>
		</ol> </li> <li> 在热压机中冷却压缩模具而不将压力释放到低于120和 #176; C, 这是预制复合材料的玻璃化转变温度. </li>
		<li> 释放压力并从热压机中取出压缩模具. </li>
		<li> 从压缩模具中脱模最终产品. </li>
	</ol>
	</li>
</ol>

<ol>
	<li>Hwang, I. U., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Bipolar+plate+made+of+carbon+fiber+epoxy+composite+for+polymer+electrolyte+membrane+fuel+cells.">Bipolar plate made of carbon fiber epoxy composite for polymer electrolyte membrane fuel cells.</a> J Power Sources. 184 (1), 90-94 (2008).</li><li>Avasarala, B., Haldar, P. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Effect+of+surface+roughness+of+composite+bipolar+plates+on+the+contact+resistance+of+a+proton+exchange+membrane+fuel+cell.">Effect of surface roughness of composite bipolar plates on the contact resistance of a proton exchange membrane fuel cell.</a> J Power Sources. 188 (1), 225-229 (2009).</li><li>Yu, H. N., Lim, J. W., Kim, M. K., Lee, D. G. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Plasma+treatment+of+the+carbon+fiber+bipolar+plate+for+PEM+fuel+cell.">Plasma treatment of the carbon fiber bipolar plate for PEM fuel cell.</a> Compos Struct. 94 (5), 1911-1918 (2012).</li><li>Lim, J. W., Lee, D. G. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Development+of+composite-metal+hybrid+bipolar+plates+for+PEM+fuel+cells.">Development of composite-metal hybrid bipolar plates for PEM fuel cells.</a> Int J Hydrogen Energy. 37 (17), (2012).</li><li>Kim, B. G., Lee, D. G. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Electromagnetic-carbon+surface+treatment+of+composite+bipolar+plate+for+high-efficiency+polymer+electrolyte+membrane+fuel+cells.">Electromagnetic-carbon surface treatment of composite bipolar plate for high-efficiency polymer electrolyte membrane fuel cells.</a> J Power Sources. 195 (6), 1577-1582 (2010).</li><li>Kim, B. G., Lim, J. W., Lee, D. G. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=A+single-type+aluminum/composite+hybrid+bipolar+plate+with+surface+modification+for+high+efficiency+PEMFC.">A single-type aluminum/composite hybrid bipolar plate with surface modification for high efficiency PEMFC.</a> Int J Hydrogen Energy. 36 (4), 3087-3095 (2011).</li><li>Yu, H. N., Lim, J. W., Suh, J. D., Lee, D. G. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=A+graphite-coated+carbon+fiber+epoxy+composite+bipolar+plate+for+polymer+electrolyte+membrane+fuel+cell.">A graphite-coated carbon fiber epoxy composite bipolar plate for polymer electrolyte membrane fuel cell.</a> J Power Sources. 196 (23), 9868-9875 (2011).</li><li>Kim, K. H., Kim, B. G., Lee, D. G. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Development+of+carbon+composite+bipolar+plate+(BP)+for+vanadium+redox+flow+battery+(VRFB).">Development of carbon composite bipolar plate (BP) for vanadium redox flow battery (VRFB).</a> Compos Struct. 109, 253-259 (2014).</li><li>Lee, D., Lim, J. W., Nam, S., Choi, I., Lee, D. G. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Gasket-integrated+carbon/silicone+elastomer+composite+bipolar+plate+for+high-temperature+PEMFC.">Gasket-integrated carbon/silicone elastomer composite bipolar plate for high-temperature PEMFC.</a> Compos Struct. 128, 284-290 (2015).</li><li>Lee, D., Lee, D. G. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Electro-mechanical+properties+of+the+carbon+fabric+composites+with+fibers+exposed+on+the+surface.">Electro-mechanical properties of the carbon fabric composites with fibers exposed on the surface.</a> Compos Struct. 140, 77-83 (2016).</li><li>Lee, D., Lim, J. W., Nam, S., Choi, I., Lee, D. G. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Method+for+exposing+carbon+fibers+on+composite+bipolar+plates.">Method for exposing carbon fibers on composite bipolar plates.</a> Compos Struct. 134, 1-9 (2015).</li><li>Lee, D., Lee, D. G. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Carbon+composite+bipolar+plate+for+high-temperature+proton+exchange+membrane+fuel+cells+(HT-PEMFCs).">Carbon composite bipolar plate for high-temperature proton exchange membrane fuel cells (HT-PEMFCs).</a> J Power Sources. 327, 119-126 (2016).</li><li>Lee, D., Choe, J., Nam, S., Lim, J. W., Choi, I., Lee, D. 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G. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Cathode/anode+integrated+composite+bipolar+plate+for+high-temperature+PEMFC.">Cathode/anode integrated composite bipolar plate for high-temperature PEMFC.</a> Compos Struct. 167, 144-151 (2017).</li><li>Lee, D., Oh, Y., Nam, S., Choe, J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Adhesion+Characteristics+of+Fiber-exposed+Glass+Composites.">Adhesion Characteristics of Fiber-exposed Glass Composites.</a> Compos Struct. 165, 9-14 (2017).</li></ol>

作者没有什么可透露的。

与传统方法相比, 软层法具有明显的优越性, 且制造成本较低。软层法制备的三种复合材料的电学性能、力学性能、透气性、附着力等方面都具有独特的特性。
对于电学性能的测量, 采用了四点探针法。对 ASR 进行了5次测量, 平均值作为双极板的代表值。共测量了五双极板, 并对误差条使用了最大和最小的 ASR 值。
由于暴露的碳纤维 (图 2a</st...

双极板是能量转换系统和能量存储系统 (如燃料电池和电池) 的多功能关键部件。双极板的关键功能要求如下: 高电导率在穿过厚度方向, 以减少欧姆损耗, 高机械性能, 承受高压实压力和外部冲击, 以及高批量生产的生产率。
与传统上采用的石墨和金属作为双极板材料相比, 碳纤维/环氧树脂复合材料具有较高的比强度和刚度, 这表明系统的重量可以大大降低用复合材料取代传统的双极板材料1。然而, 传统的碳/环氧复合材料在穿透厚度方向上的导电性较差, 导致了大面积的电阻 (ASR), 这是由于复合表面上形成了树脂丰富的层。该绝缘树脂层防止导电炭纤维与相邻元件之间的直接接触, 如另双极板、气体扩散层 (GDL) 和碳毡电极。
许多研究是为了解决高 ASR 由于树脂丰富的层。第一种方法是表面处理方法, 以选择性地去除树脂丰富的层。例如, 机械磨损试图去除表面上的树脂2。然而, 碳纤维也被损坏, 导致了一个糟糕的 ASR。等离子体处理3、4和微波处理方法5、6也被开发以避免纤维损坏, 但它们导致生产率和均匀性低下。第二种方法, 导电层涂层方法, 包括膨胀石墨涂层7,8。该方法成功地降低了 ASR, 被认为是制造复合双极板的标准方法。然而, 它是昂贵的, 有耐久性和分层问题, 由于机械强度低。
在这项研究中, "软层法", 一种新的制造方法, 可以暴露碳纤维的复合双极板表面, 证明。该方法的主要目的是获得低的 ASR, 低的制造成本。软层法采用薄软层, 如在压缩模和双极板之间的聚合物释放膜。在压缩模和软层分离后, 制备的双极板显示在表面上暴露的碳纤维, 无任何 post-surface 处理。该方法不仅降低了 ASR, 而且大大提高了机械性能, 解决了气体渗透性问题。这种方法可用于许多其他用途: 发展一个导电板, 制造一个薄的复合材料, 和制造的粘合剂连接没有表面处理。

<table><tbody><tr><td>Unidirectional carbon/epoxy prepreg</td><td>SK Chemicals</td><td>USN020</td><td>Used to fabricate unidirectional carbon composite</td></tr><tr><td>Plain weave carbon fabric/epoxy prepreg</td><td>SK Chemicals</td><td>WSN 1k</td><td>Used to fabricate fabric carbon composite</td></tr><tr><td>Plain weave carbon fabric</td><td>SK Chemicals</td><td>C-112</td><td>Used to fabricate fabric carbon composite</td></tr><tr><td>Non-woven carbon felt</td><td>Newell</td><td>Graphite felt 3 mm</td><td>Used to fabricated felt carbon composite</td></tr><tr><td>Film type epoxy resin</td><td>SK Chemicals</td><td>K51</td><td>Used as a matrix of the composite</td></tr><tr><td>Acetone 99.5%</td><td>Samchun</td><td>67-64-1</td><td>Used to cleanse the carbon fiber and the soft layers</td></tr><tr><td>Mold release</td><td>ShinEtsu</td><td>KF-96</td><td>Used to coat the mold</td></tr><tr><td>Release film</td><td>Airtech</td><td>A4000V</td><td>Used as a soft layer</td></tr><tr><td>Compression mold</td><td>N/A</td><td>N/A</td><td>Machined in lab. Material: NAK80</td></tr><tr><td>Hot press</td><td>Hydrotek 100</td><td>N/A</td><td>Used to apply pressure and heat</td></tr><tr><td>Scanning electron microscope</td><td>FEI Compnay</td><td>Magellan 400</td><td>Used to investigate the surface of the composite</td></tr></tbody></table>

experimental implementation of a new composite fabrication method: exposing bare fibers on the composite surface by the soft layer method

双极板是质子交换膜燃料电池 (电池) 和钒氧化还原流电池 (VRFBs) 的关键部件。它是一种具有高导电性、高机械性能和高生产率的多功能元件。
在这方面, 碳纤维/环氧树脂复合材料可以是取代传统的石墨双极板的理想材料, 这往往导致整个系统的灾难性故障, 因为其固有的脆性。虽然碳/环氧树脂复合材料具有很高的机械性能, 易于制造, 但由于在其表面形成了富树脂层, 所以通过厚度方向的导电性较差。因此, 采用膨胀石墨涂层来解决导电问题。然而, 膨胀石墨涂层不仅增加了制造成本, 而且机械性能较差。
在本研究中, 展示了一种在复合表面上暴露纤维的方法。目前有许多方法可以暴露纤维的表面处理后, 复合材料的制造。然而, 这种新方法不需要表面处理, 因为纤维是在复合材料制造过程中暴露出来的。通过暴露表面裸露的碳纤维, 使复合材料的导电性和机械强度大幅度提高。

使用扫描电子显微镜 (SEM) (图 1) 观察制作的标本。因为覆盖纤维顶端的富树脂层只有几微米厚, 在标本顶部观察到的光学显微图像是不合适的。通过5倾斜标本观察到的 SEM 图像提供了更具代表性的图像。与传统的模压成型复合材料相比, 采用软层法制备复合材料, 其表面覆盖有树脂, 裸露纤维无缺陷。软层法适用于单向碳复合材料、炭纤维复合材料和?...

Watch this Scientific Journal Video about Experimental Implementation of a New Composite Fabrication Method: Exposing Bare Fibers on the Composite Surface by the Soft Layer Method at JoVE.com

Experimental Implementation of a New Composite Fabrication Method: Exposing Bare Fibers on the Composite Surface by the Soft Layer Method

提出了一种通过消除树脂富区来暴露复合材料表面裸露纤维的协议。纤维被暴露在复合材料的制造过程中, 而不是通过后表面处理。暴露的碳基复合材料在穿透厚度方向和高机械性能上表现出较高的电导率。

一种新的复合制备方法的实验实现: 用软层法对复合材料表面裸露纤维进行曝光

The bipolar plate is a key component in proton exchange membrane fuel cells (PEMFCs) and vanadium redox flow batteries (VRFBs). It is a multi-functional ...

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JoVE Journal

Engineering

8.3K 次观看.  Korea Advanced Institute of Science and Technology. 提出了一种通过消除树脂富区来暴露复合材料表面裸露纤维的协议。纤维被暴露在复合材料的制造过程中, 而不是通过后表面处理。暴露的碳基复合材料在穿透厚度方向和高机械性能上表现出较高的电导率。

视频: Experimental Implementation of a New Composite Fabrication Method: Exposing Bare Fibers on the Composite Surface by the Soft Layer Method

Fabricating Metamaterials Using the Fiber Drawing Method

Metamaterials are man-made composite materials, fabricated by assembling components much smaller than the wavelength at which they operate 1. They owe their electromagnetic properties to the structure of their constituents, instead of the atoms that compose them. For example, sub-wavelength metal wires can be arranged to possess an effective electric permittivity that is either positive or negative at a given frequency, in contrast to the metals themselves 2. This unprecedented control over the behaviour of light can potentially lead to a number of novel devices, such as invisibility cloaks 3, negative refractive index materials 4, and lenses that resolve objects below the diffraction limit 5. However, metamaterials operating at optical, mid-infrared and terahertz frequencies are conventionally made using nano- and micro-fabrication techniques that are expensive and produce samples that are at most a few centimetres in size 6-7. Here we present a fabrication method to produce hundreds of meters of metal wire metamaterials in fiber form, which exhibit a terahertz plasmonic response 8. We combine the stack-and-draw technique used to produce microstructured polymer optical fiber 9 with the Taylor-wire process 10, using indium wires inside polymethylmethacrylate (PMMA) tubes. PMMA is chosen because it is an easy to handle, drawable dielectric with suitable optical properties in the terahertz region; indium because it has a melting temperature of 156.6 &deg;C which is appropriate for codrawing with PMMA. We include an indium wire of 1 mm diameter and 99.99% purity in a PMMA tube with 1 mm inner diameter (ID) and 12 mm outside diameter (OD) which is sealed at one end. The tube is evacuated and drawn down to an outer diameter of 1.2 mm. The resulting fiber is then cut into smaller pieces, and stacked into a larger PMMA tube. This stack is sealed at one end and fed into a furnace while being rapidly drawn, reducing the diameter of the structure by a factor of 10, and increasing the length by a factor of 100. Such fibers possess features on the micro- and nano- scale, are inherently flexible, mass-producible, and can be woven to exhibit electromagnetic properties that are not found in nature. They represent a promising platform for a number of novel devices from terahertz to optical frequencies, such as invisible fibers, woven negative refractive index cloths, and super-resolving lenses.

Metamaterials at terahertz frequencies offer unique opportunities, but are challenging to fabricate in bulk. We adapt the fabrication procedure for microstructured polymer optical fibers to inexpensively fabricate metamaterials potentially on an industrial scale. We produce polymethylmethacrylate fibers containing ~10 &mu;m diameter indium wires separated by ~100 &mu;m, which exhibit a terahertz plasmonic response.

制造超材料使用光纤拉丝法

Metamaterials are man-made composite materials, fabricated by assembling components much smaller than the wavelength at which they operate 1. They owe ...

科研

工程学

Process of Making Three-dimensional Microstructures using Vaporization of a Sacrificial Component

Vascular structures in natural systems are able to provide high mass transport through high surface areas and optimized structure. Few synthetic material fabrication techniques are able to mimic the complexity of these structures while maintaining scalability. The Vaporization of a Sacrificial Component (VaSC) process is able to do so. This process uses sacrificial fibers as a template to form hollow, cylindrical microchannels embedded within a matrix. Tin (II) oxalate (SnOx) is embedded within poly(lactic) acid (PLA) fibers which facilitates the use of this process. The SnOx catalyzes the depolymerization of the PLA fibers at lower temperatures. The lactic acid monomers are gaseous at these temperatures and can be removed from the embedded matrix at temperatures that do not damage the matrix. Here we show a method for aligning these fibers using micromachined plates and a tensioning device to create complex patterns of three-dimensionally arrayed microchannels. The process allows the exploration of virtually any arrangement of fiber topologies and structures.

The Vaporization of a Sacrificial Component (VaSC) process is used to fabricate microvascular structures. This procedure uses sacrificial poly(lactic) acid fibers to form hollow microchannels with precise 3D geometric positioning provided by laser micromachined guide plates.

制作三维微结构，用牺牲部分汽化过程

Vascular structures in natural systems are able to provide high mass transport through high surface areas and optimized structure. Few synthetic material ...

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

Strain Sensing Based on Multiscale Composite Materials Reinforced with Graphene Nanoplatelets

The electrical response of NH2-functionalized graphene nanoplatelets composite materials under strain was studied. Two different manufacturing methods are proposed to create the electrical network in this work: (a) the incorporation of the nanoplatelets into the epoxy matrix and (b) the coating of the glass fabric with a sizing filled with the same nanoplatelets. Both types of multiscale composite materials, with an in-plane electrical conductivity of ~10-3 S/m, showed an exponential growth of the electrical resistance as the strain increases due to distancing between adjacent functionalized graphene nanoplatelets and contact loss between overlying ones. The sensitivity of the materials analyzed during this research, using the described procedures, has been shown to be higher than commercially available strain gauges. The proposed procedures for self-sensing of the structural composite material would facilitate the structural health monitoring of components in difficult to access emplacements such as offshore wind power farms. Although the sensitivity of the multiscale composite materials was considerably higher than the sensitivity of metallic foils used as strain gauges, the value reached with NH2 functionalized graphene nanoplatelets coated fabrics was nearly an order of magnitude superior. This result elucidated their potential to be used as smart fabrics to monitor human movements such as bending of fingers or knees. By using the proposed method, the smart fabric could immediately detect the bending and recover instantly. This fact permits precise monitoring of the time of bending as well as the degree of bending.

The integration of conductive nanoparticles, such as graphene nanoplatelets, into glass fiber composite materials creates an intrinsic electrical network susceptible to strain. Here, different methods to obtain strain sensors based on the addition of graphene nanoplatelets into the epoxy matrix or as a coating on glass fabrics are proposed.

基于多尺度复合材料的增强与石墨烯纳米片应变传感

The electrical response of NH2-functionalized graphene nanoplatelets composite materials under strain was studied. Two different manufacturing methods are ...

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 ...

生物工程

Magnet Assisted Composite Manufacturing: A Flexible New Technique for Achieving High Consolidation Pressure in Vacuum Bag/Lay-Up Processes

This work demonstrates a protocol to improve the quality of composite laminates fabricated by wet lay-up vacuum bag processes using the recently developed magnet assisted composite manufacturing (MACM) technique. In this technique, permanent magnets are utilized to apply a sufficiently high consolidation pressure during the curing stage. To enhance the intensity of the magnetic field, and thus, to increase the magnetic compaction pressure, the magnets are placed on a magnetic top plate. First, the entire procedure of preparing the composite lay-up on a magnetic bottom steel plate using the conventional wet lay-up vacuum bag process is described. Second, placement of a set of Neodymium-Iron-Boron permanent magnets, arranged in alternating polarity, on the vacuum bag is illustrated. Next, the experimental procedures to measure the magnetic compaction pressure and volume fractions of the composite constituents are presented. Finally, methods used to characterize microstructure and mechanical properties of composite laminates are discussed in detail. The results prove the effectiveness of the MACM method in improving the quality of wet lay-up vacuum bag laminates. This method does not require large capital investment for tooling or equipment and can also be used to consolidate geometrically complex composite parts by placing the magnets on a matching top mold positioned on the vacuum bag.

A new technique for applying consolidation pressure on the vacuum bag lay-up to fabricate composite laminates is described. The goal of this protocol is to develop a simple, cost-effective technique to improve the quality of laminates fabricated by the wet lay-up vacuum bag method.

磁铁辅助复合制造: 真空袋/糊化过程中实现高固结压力的一种柔性新技术

This work demonstrates a protocol to improve the quality of composite laminates fabricated by wet lay-up vacuum bag processes using the recently developed ...

Multiscale Structures Aggregated by Imprinted Nanofibers for Functional Surfaces

Multiscale surface structures have attracted increasing interest owing to several potential applications in surface devices. However, an existing challenge in the field is the fabrication of hybrid micro-nano structures using a facile, cost-effective, and high-throughput method. To overcome these challenges, this paper proposes a protocol to fabricate multiscale structures using only an imprint process with an anodic aluminum oxide (AAO) filter and an evaporative self-aggregation process of nanofibers. Unlike previous attempts that have aimed to straighten nanofibers, we demonstrate a unique fabrication method for multiscale aggregated nanofibers with high aspect ratios. Furthermore, the surface morphology and wettability of these structures on various liquids were investigated to facilitate their use in multifunctional surfaces.

Presented is an easy method to fabricate nano-micro multiscale structures, for functional surfaces, by aggregating nanofibers fabricated using an anodic aluminum oxide filter.

功能表面用印迹纳米纤维聚合的多尺度结构

Multiscale surface structures have attracted increasing interest owing to several potential applications in surface devices. However, an existing ...

Fabrication and Design of Wood-Based High-Performance Composites

Delignified densified wood is a new promising and sustainable material that possesses the potential to replace synthetic materials, such as glass fiber reinforced composites, due to its excellent mechanical properties. Delignified wood, however, is rather fragile in a wet state, which makes handling and shaping challenging. Here we present two fabrication processes, closed-mold densification and vacuum densification, to produce high-performance cellulose composites based on delignified wood, including an assessment of their advantages and limitations. Further, we suggest strategies for how the composites can be re-used or decomposed at the end-of-life cycle. Closed-mold densification has the advantage that no elaborate lab equipment is needed. Simple screw clamps or a press can be used for densification. We recommend this method for small parts with simple geometries and large radii of curvature. Vacuum densification in an open-mold process is suitable for larger objects and complex geometries, including small radii of curvature. Compared to the closed-mold process, the open-mold vacuum approach only needs the manufacture of a single mold cavity.

Delignified densified wood represents a new promising lightweight, high-performance and bio-based material with great potential to partially substitute natural fiber reinforced- or glass fiber reinforced composites in the future. We here present two versatile fabrication routes and demonstrate the possibility to create complex composite parts.

基于木材的高性能复合材料的制造与设计

Delignified densified wood is a new promising and sustainable material that possesses the potential to replace synthetic materials, such as glass fiber ...

纤维复合材料层压板的制造和机械性能评估

Measuring the Mechanical Properties of Glass Fiber Reinforcement Polymer Composite Laminates Obtained by Different Fabrication Processes

The traditional wet hand lay-up process (WL) has been widely applied in the manufacturing of fiber composite laminates. However, due insufficiency in the forming pressure, the mass fraction of fiber is reduced and lots of air bubbles are trapped inside, resulting in low-quality laminates (low stiffness and strength). The wet hand lay-up/vacuum bag (WLVB) process for the fabrication of composite laminates is based on the traditional wet hand lay-up process, using a vacuum bag to remove air bubbles and provide pressure, and then carrying out the heating and curing process. 
Compared with the traditional hand lay-up process, laminates manufactured by the WLVB process show superior mechanical properties, including better strength and stiffness, higher fiber volume fraction, and lower void volume fraction, which are all benefits for composite laminates. This process is completely manual, and it is greatly influenced by the skills of the preparation personnel. Therefore, the products are prone to defects such as voids and uneven thickness, leading to unstable qualities and mechanical properties of the laminate. Hence, it is necessary to finely describe the WLVB process, finely control steps, and quantify material ratios, in order to ensure the mechanical properties of laminates. 
This paper describes the meticulous process of the WLVB process for preparing woven plain patterned glass fiber reinforcement composite laminates (GFRPs). The fiber volume content of laminates was calculated using the formula method, and the calculated results showed that the fiber volume content of WL laminates was 42.04%, while that of WLVB laminates was 57.82%, increasing by 15.78%. The mechanical properties of the laminates were characterized using tensile and impact tests. The experimental results revealed that with the WLVB process, the strength and modulus of the laminates were enhanced by 17.4% and 16.35%, respectively, and the specific absorbed energy was increased by 19.48%.

作者聚焦：使用湿法手糊/真空袋工艺提高纤维复合材料层压板质量 

This paper describes a fabrication process for fiber-reinforced polymer matrix composite laminates obtained using the wet hand lay-up/vacuum bag method.

测量通过不同制造工艺获得的玻璃纤维增强聚合物复合层压板的机械性能

The traditional wet hand lay-up process (WL) has been widely applied in the manufacturing of fiber composite laminates. However, due insufficiency in the ...

一种新的复合制备方法的实验实现: 用软层法对复合材料表面裸露纤维进行曝光

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此视频中的章节

制造超材料使用光纤拉丝法

制作三维微结构，用牺牲部分汽化过程

通过微流体渗透制备三维微结构纳米复合材料的制造

基于多尺度复合材料的增强与石墨烯纳米片应变传感

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

磁铁辅助复合制造: 真空袋/糊化过程中实现高固结压力的一种柔性新技术

功能表面用印迹纳米纤维聚合的多尺度结构

基于木材的高性能复合材料的制造与设计

测量通过不同制造工艺获得的玻璃纤维增强聚合物复合层压板的机械性能

测量通过不同制造工艺获得的玻璃纤维增强聚合物复合层压板的机械性能