Name: nanothermite with meringue-like morphology: from loose powder to ultra-porous objects
Uploaded: 2017-12-24T13:00:00.000+00:00
Duration: 7 min 46 s
Description: Watch this Scientific Journal Video about Nanothermite with Meringue-like Morphology: From Loose Powder to Ultra-porous Objects at JoVE.com

作者要感谢 ISL 的摄影师, 伊夫 Suma 和雅尼克 Boehrer, 为样品的照片和观察由高速视频的合成和燃烧的 nanothermite 泡沫。他们还想对他们的同事 Dr. 文森特 Pichot 从 NS3E 实验室的 X 射线衍射表征材料表示感谢。

警告: 执行本文中描述的所有反应, 在一个具有装甲窗口的爆炸证明的会议厅, 允许通过高速视频对发泡/燃烧过程进行目视检查和观察。注意铝成分的潜在点火和空气中氢气爆炸引起的实验风险。为此, 总是在一个装有适当排气通风的爆炸证明的房间里工作。请记住, 关于高能材料的实验必须由有经验的科学家进行, 他们充分意识到烟火的危害, 并且所有的测试都必须按照当地法律和安全条例进行。请注意, 作者拒绝对这些结果的不当使用承担任何责任。
1. 铝矩阵的编制
注: 实验在室温 (15-25 ° c) 下进行。
<ol>
	<li>重3.00 克铝纳米。</li>
	<li>在150毫升烧杯中重4.00 克的商业溶液 (85%) 的正磷酸酸 (H3PO4); 将酸滴与3毫升的聚乙烯巴斯德吸管一起添加。
	<ol>
		<li>可选地, 从 0-2 毫升的去离子水的体积可以添加到正磷酸酸。</li>
		<li>质的解决方案, 放慢旋转烧杯的手约 100 rpm。</li>
	</ol>
	</li>
	<li>将装有酸的烧杯放在爆炸室中。</li>
	<li>将步骤1.1 中称重的铝纳米倒入包含 H3PO4解决方案的烧杯中。</li>
	<li>用不锈钢刮刀快速搅拌;在不到一分钟的时间内执行此步骤。</li>
	<li>立即关闭爆炸室。</li>
	<li>等到发泡反应发生。</li>
	<li>之后, 等待额外的10分钟, 铝矩阵冷却。</li>
	<li>使用实验室弓钳将烧杯从爆炸室中取出。</li>
	<li>通过小心地打破烧杯壁来恢复样品。当心酸性残留物的存在, 不要用手套来处理这些材料。</li>
</ol>
2. Nanothermite 泡沫的合成
注: 实验在室温下 (15-25 ° c) 进行。
<ol>
	<li>nanothermite 合剂的制备
	<ol>
		<li>在一个100毫升的圆形底烧瓶, 分别称3.00 克和3.45 克 Al 和禾3纳米粉。</li>
		<li>混合在 2500 rpm 运行的涡流混频器的纳米粉。</li>
		<li>用不锈钢刮刀轻轻搅拌混合质。在操作过程中, 避免圆底烧瓶玻璃墙与刮刀之间的任何摩擦。 注意: 在这一步, 实验者必须接地, 以避免任何静电放电, 这可能导致混合物的点火。</li>
		<li>重复操作2.1.2。</li>
	</ol>
	</li>
	<li>准备 H 3 PO 4解决方案
	<ol>
		<li>在150毫升烧杯中重4.00 克的商业溶液 (85%) 的正磷酸酸 (H3PO4); 将酸滴与3毫升的聚乙烯巴斯德吸管一起添加。</li>
		<li>准备稀释的 H3PO4解决方案:<ol>
			<li>采取步骤2.2.1 准备的样品, 并添加0至2毫升去水与1毫升聚乙烯巴斯德吸管。</li>
			<li>用手在大约 100 rpm 的速度下用的烧杯的缓慢旋转运动质溶液。</li>
		</ol>
		</li>
	</ol>
	</li>
	<li>nanothermite 泡沫的制备
	<ol>
		<li>将装有酸的烧杯放在爆炸室的2.2 步中。</li>
		<li>将步骤2.1 中准备的 nanothermite 倒入包含 H3PO4解决方案的烧杯中。</li>
		<li>用不锈钢刮刀快速搅拌;在不到一分钟的时间内执行此步骤。</li>
		<li>立即关闭爆炸室。</li>
		<li>等到发泡反应发生。</li>
		<li>之后, 等待额外的10分钟冷却下来的 nanothermite 泡沫。</li>
		<li>用实验室的弓钳将烧杯从爆炸室中取出。</li>
		<li>通过小心地打破烧杯壁来恢复样品。当心酸性残留物的存在, 避免使用无手套的材料。</li>
	</ol>
	</li>
</ol>
3. Nanothermite 泡沫的燃烧
<ol>
	<li>将在步骤1.10 中准备的铝矩阵或在爆炸室中的台阶2.3.8 中制备的 nanothermite 泡沫。</li>
	<li>放置一个烟火点火器接近样品从步骤3.1。</li>
	<li>关闭爆炸室</li>
	<li>将点火器连接到一个安全的电子设备。</li>
	<li>点燃烟火链</li>
	<li>观察燃烧通过装甲窗口与一个超快相机运行在1万至3万帧/秒。</li>
</ol>

<ol>
	<li>Comet, M., Martin, C., Schnell, F., Spitzer, D. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Nanothermite+foams:+From+nanopowder+to+object.">Nanothermite foams: From nanopowder to object.</a> Chem. Eng. J. 316, 807-812 (2017).</li><li>Lafontaine, E., Comet, M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=.">.</a> Nanothermites. , (2016).</li><li>Comet, M., 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=Preparation+of+Cr2O3+nanoparticles+for+superthermites+by+the+detonation+of+an+explosive+nanocomposite+material.">Preparation of Cr2O3 nanoparticles for superthermites by the detonation of an explosive nanocomposite material.</a> J. Nanopart. Res. 13 (5), 1961-1969 (2011).</li><li>Gibot, P., 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=Highly+Insensitive/Reactive+Thermite+Prepared+from+Cr2O3+Nanoparticles.">Highly Insensitive/Reactive Thermite Prepared from Cr2O3 Nanoparticles.</a> Propell. Explos. Pyrot. 36 (1), 80-87 (2011).</li><li>Tillotson, T. M., Gash, A. E., Simpson, R. L., Hrubesh, L. W., Satcher, J. H., Poco, J. F. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Nanostructured+energetic+materials+using+sol-gel+methodologies.">Nanostructured energetic materials using sol-gel methodologies.</a> J. Non-Cryst. Solids. 285 (1-3), 338-345 (2001).</li><li>Yang, Y., 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=Hierarchical+MnO2/SnO2+Heterostructures+for+a+Novel+Free-Standing+Ternary+Thermite+Membrane.">Hierarchical MnO2/SnO2 Heterostructures for a Novel Free-Standing Ternary Thermite Membrane.</a> Inorg. Chem. 52 (16), 9449-9455 (2013).</li><li>Prentice, D., Pantoya, M. L., Gash, A. E. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Combustion+Wave+Speeds+of+Sol-Gel-Synthesized+Tungsten+Trioxide+and+Nano-Aluminum:+The+Effect+of+Impurities+on+Flame+Propagation.">Combustion Wave Speeds of Sol-Gel-Synthesized Tungsten Trioxide and Nano-Aluminum: The Effect of Impurities on Flame Propagation.</a> Energ. Fuel. 20 (6), 2370-2376 (2006).</li><li>Bockmon, B. S., Pantoya, M. L., Son, S. F., Asay, B. W., Mang, J. T. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Combustion+velocities+and+propagation+mechanisms+of+metastable+interstitial+composites.">Combustion velocities and propagation mechanisms of metastable interstitial composites.</a> Appl. Phys. Lett. 98, 064903 (2005).</li><li>Apperson, S., 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=Generation+of+fast+propagating+combustion+and+shock+waves+with+copper+oxide/aluminum+nanothermite+composites.">Generation of fast propagating combustion and shock waves with copper oxide/aluminum nanothermite composites.</a> Appl. Phys. Lett. 91, 243109 (2007).</li><li>Wang, L., Luss, D., Martirosyan, K. S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+behavior+of+nanothermite+reaction+based+on+Bi2O3/Al.">The behavior of nanothermite reaction based on Bi2O3/Al.</a> J. Appl. Phys. 110, 074311 (2011).</li><li>Martirosyan, K. S., Wang, L., Vicent, A., Luss, D. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Synthesis+and+performances+of+bismuth+trioxide+nanoparticles+for+high+energy+gas+generator+use.">Synthesis and performances of bismuth trioxide nanoparticles for high energy gas generator use.</a> Nanotechnology. 20 (8), 405609 (2009).</li><li>Armstrong, R. W., Baschung, B., Booth, D. W., Samirant, M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Enhanced+Propellant+Combustion+with+Nanoparticles.">Enhanced Propellant Combustion with Nanoparticles.</a> Nano Lett. 3 (2), 253-255 (2003).</li><li>Wu, C., Sullivan, K., Chowdhury, S., Jian, G., Zhou, L., Zachariah, M. R. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Encapsulation+of+Perchlorate+Salts+within+Metal+Oxides+for+Application+as+Nanoenergetic+Oxidizers.">Encapsulation of Perchlorate Salts within Metal Oxides for Application as Nanoenergetic Oxidizers.</a> Adv. Funct. Mater. 22 (1), 78-85 (2012).</li><li>Sullivan, K. T., Piekiel, N. W., Chowdhury, S., Wu, C., Zachariah, M. R., Johnson, C. E. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Ignition+and+Combustion+Characteristics+of+Nanoscale+Al/AgIO3:+A+Potential+Energetic+Biocidal+System.">Ignition and Combustion Characteristics of Nanoscale Al/AgIO3: A Potential Energetic Biocidal System.</a> Combust. Sci. Technol. 183 (3), 285-302 (2010).</li><li>Wang, H., Jian, G., Zhou, W., Delisio, J. B., Lee, V. T., Zachariah, M. R. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Metal+iodate-based+energetic+composites+and+their+combustion+and+biocidal+performances.">Metal iodate-based energetic composites and their combustion and biocidal performances.</a> ACS Appl. Mater. Interfaces. 7 (31), 17363-17370 (2015).</li><li>Jian, G., Feng, J., Jacob, R. J., Egan, G. C., Zachariah, M. R. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Super-reactive+Nanoenergetic+Gas+Generators+Based+on+Periodate+Salts.">Super-reactive Nanoenergetic Gas Generators Based on Periodate Salts.</a> Angew. Chem. Int. Ed. 52 (37), 9743-9746 (2013).</li><li>Comet, M., Vidick, G., Schnell, F., Suma, Y., Baps, B., Spitzer, D. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Sulfates-Based+Nanothermites:+An+Expanding+Horizon+for+Metastable+Interstitial+Composites.">Sulfates-Based Nanothermites: An Expanding Horizon for Metastable Interstitial Composites.</a> Angew. Chem. Int. Ed. 54 (15), 4458-4462 (2015).</li><li>Zhou, W., Delisio, J. B., Li, X., Liu, L., Zachariah, M. R. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Persulfate+salt+as+an+oxidizer+for+biocidal+energetic+nano-thermites.">Persulfate salt as an oxidizer for biocidal energetic nano-thermites.</a> J. Mater. Chem. A. 3 (22), 11838-11846 (2015).</li><li>Sun, J., Pantoya, M. L., Simon, S. L. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Dependence+of+size+and+size+distribution+on+reactivity+of+aluminum+nanoparticles+in+reactions+with+oxygen+and+MoO3.">Dependence of size and size distribution on reactivity of aluminum nanoparticles in reactions with oxygen and MoO3.</a> Thermochim. Acta. 444 (2), 117-127 (2006).</li><li>Levitas, V. I., Asay, B. W., Son, S. F., Pantoya, M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Melt+dispersion+mechanism+for+fast+reaction+of+nanothermites.">Melt dispersion mechanism for fast reaction of nanothermites.</a> Appl. Phys. Lett. 89, 071909 (2006).</li><li>Park, E. -. J., Kim, H., Kim, Y., Choi, K. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Repeated-dose+toxicity+attributed+to+aluminum+nanoparticles+following+28-day+oral+administration,+particularly+on+gene+expression+in+mouse+brain.">Repeated-dose toxicity attributed to aluminum nanoparticles following 28-day oral administration, particularly on gene expression in mouse brain.</a> Toxicol. Environ. Chem. 93 (1), 120-133 (2011).</li><li>Walter, K. C., Aumann, C. E., Carpenter, R. D., O'Neill, E. H., Pesiri, D. R. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Energetic+materials+development+at+technanogy+materials+development.">Energetic materials development at technanogy materials development.</a> Mater. Res. Soc. Symp. Proc. 800, 27-37 (2004).</li><li>Khasainov, B., Comet, M., Veyssi&#232;re, B., Spiter, D. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Comparison+of+performance+of+fast–reacting+nanothermites+and+primary+explosives.">Comparison of performance of fast–reacting nanothermites and primary explosives.</a> Propell. Explos. Pyrot. , (2017).</li><li>Siegert, B., Comet, M., Spitzer, D. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Safer+energetic+materials+by+a+nanotechnological+approach.">Safer energetic materials by a nanotechnological approach.</a> Nanoscale. 3, 3534-3544 (2011).</li><li>Sullivan, K. T., Kuntz, J. D., Gash, A. E. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Electrophoretic+deposition+and+mechanistic+studies+of+nano-Al/CuO+thermites.">Electrophoretic deposition and mechanistic studies of nano-Al/CuO thermites.</a> J. Appl. Phys. 112, 024316 (2012).</li><li>Blobaum, K. J., Reiss, M. E., Plitzko, J. M., Weihs, T. P. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Deposition+and+characterization+of+a+self-propagating+CuOx/Al+thermite+reaction+in+a+multilayer+foil+geometry.">Deposition and characterization of a self-propagating CuOx/Al thermite reaction in a multilayer foil geometry.</a> J. Appl. Phys. 94 (5), 2915-2922 (2003).</li><li>Gash, A. E., Tillotson, T. M., Satcher, J. H., Poco, J. F., Hrubesh, L. W., Simpson, R. L. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Use+of+epoxides+in+the+sol-gel+synthesis+of+porous+iron+(III)+oxide+monoliths+from+Fe(III)+salts.">Use of epoxides in the sol-gel synthesis of porous iron (III) oxide monoliths from Fe(III) salts.</a> Chem. Mater. 13 (3), 999-1007 (2001).</li><li>Yan, S., Jian, G., Zachariah, M. R. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Electrospun+nanofiber-based+thermite+textiles+and+their+reactive+properties.">Electrospun nanofiber-based thermite textiles and their reactive properties.</a> ACS Appl. Mater. Interfaces. 4, 6432-6435 (2012).</li><li>Puszynski, J. A., Groven, L. J., Altavilla, C., Ciliberto, E. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Formation+of+nanosized+aluminum+and+its+applications+in+condensed+phase+reactions.">Formation of nanosized aluminum and its applications in condensed phase reactions.</a> Inorganic nanoparticles. Synthesis, applications and perspectives. , (2011).</li><li>Shimizu, T. A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Concept+and+the+use+of+negative+explosives.">Concept and the use of negative explosives.</a> Proceedings of the 11th International Pyrotechnics Seminar, Vail, Colorado, July 7-11. , (1986).</li><li>Molkov, V. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=.">.</a> Fundamentals of Hydrogen Safety Engineering. 1, (2012).</li><li>Comet, M., Martin, C., Klaum&#252;nzer, M., Schnell, F., Spitzer, D. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Energetic+nanocomposites+for+detonation+initiation+in+high+explosives+without+primary+explosives.">Energetic nanocomposites for detonation initiation in high explosives without primary explosives.</a> Appl. Phys. Lett. 107, 243108 (2015).</li></ol>

我们没有什么要透露的。

为了安全起见, 必须迅速进行粉体与酸的混合过程和爆炸室的关闭。反应延迟可能在某种程度上变化 (1-10 min), 这取决于实验条件。当室温过高或外部热源如聚光灯的存在时, 它会缩短, 这会引起发泡反应的早期活化。反之, 当室温较低时, 它会增加。在太多的起泡延迟 (和 #62; 15 分钟) 的情况下, 可以通过快速地将大量的水倒入烧杯 (100 毫升) 来阻止反应。铝基体或 nanothermite 泡沫的制备必须在室温 (15...

本文报告了一种将纳米铝混合物 (Al/窝3) 从松散粉末状态转换为泡沫1的方法。Nanothermites 是快速燃烧的能量组合物, 是最频繁地由金属氧化物或盐的物理混合准备以一个减少的金属, 以粉末状的形式2。用于准备 nanothermites 的最具代表性的氧化物是 Cr2O33,4, Fe2O35, MnO26, 沃 3 7, MoO38, 厝9和 Bi2O31011, 而使用的金属盐是氯酸12,13, 盐14,15,periodates16, 硫化17或 persulfates18。铝纳米是最好的选择, 作为燃料 nanothermites 由于其众多的可取性质, 如高氧化热 (10-25 焦/克)19, 快速反应动力学20, 低毒性21,和公平稳定程度一旦它已经准确地钝化22。
在基 nanothermites, 火焰锋在高速传播 (0.1-2.5 公里/秒), 但是, 这不能被视为爆炸23。反应机理实际上是由热气体在未材料孔隙中的对流驱动的。换言之, 孔隙率是 nanothermites 快速燃烧的必要条件。然而, 从物理角度看, 松散的 nanothermite 粉是不稳定的。它们被冲击或振动压实, 其最致密的成分 (通常是氧化物) 通过重力的作用逐渐与成分分离。nanothermite 孔隙度的稳定是其在未来烟火系统中集成的关键挑战。
本发明所述的制备过程的主要优点是赋予高孔隙、固态、nanothermite 的巨, 可通过将其形成的糊状物成型。此外, nanothermite 泡沫是相当不敏感的冲击, 摩擦和静电放电相比, nanothermite 松散粉末。这种不灵敏使他们特别安全处理和机器, 例如通过锯或钻。
当松散的 nanothermite 粉末被压制或颗粒时, 其孔隙度降低, 物体形成。这些材料的凝聚来源于表面作用力, 它们负责纳米粒子的聚集。在碳纳米纤维存在的情况下, nanothermite 球团的机械强度可以提高, 这是加强这些物体的一个框架24。不幸的是, 压力强烈地降低了 nanothermites 的反应性。根据学徒et al., 纳米-铝/纳米-禾3组合物的压制导致它们的反应速度由两个数量级的7的崩溃。总之, 与大多数炸药相反, nanothermites 不能通过压制来形成。
到目前为止, 在 nanothermites 的科学文献中, 很少有关于构造 nanothermites 的方法。Nanothermites 可以沉积在基板上, 无论是从其组分的粉末分散到液体介质通过电泳25, 或通过溅射其组件在连续层的26。这两种方法都导致致密沉积物, 它们比松散的粉末反应更少, 并倾向于从其制备的基质中分层。
玛丽·泰洛特森et al.提出了由 nanothermite 组成的 "三维" 物体的制备方法5, 使用由切口et al.开发的溶胶-凝胶合成, 由金属盐的胶凝溶液环27组成。Nanothermite 巨是在溶胶中分散 Al 纳米, 然后再进行凝胶制备。该凝胶随后在热室中干燥, 以产生干或由使用超临界 CO2获得气凝胶的复杂过程。Nanothermite 气凝胶不仅具有很强的反应性, 而且由于其优异的机械性能, 也可以加工。此外, 溶胶-凝胶工艺允许一个合成微孔材料和在混合燃料 (铝) 和氧化物之间无与伦比程度的同质性。尽管有这些有趣的特点, 溶胶-凝胶过程的使用是有限的: (i) 批次综合的复杂性, 这取决于许多参数;(二) 在最终材料中不可避免地存在合成副产品 (杂质), 以及 (iii) 过程的不同步骤所需的很长时间。
nanothermite 的可燃垫由硝化纤维素 (粘合剂) 的静电纺丝制备而成, 由铝和氧化铜的溶液28。这些 nanothermite 毡是由纤维组成的微米鳞片直径, 这是先验无渗透性。在这些材料中, 孔隙度是由纤维纠缠所定义的。nanothermite 垫的样品燃烧缓慢 (0.06-1.06 米/秒) 相比, 纯纳米铝/厝混合物在一个松散的粉末状态, 其中火焰前传播的速度几百米/秒29。最后, 使用硝化纤维作为粘合剂的 nanothermites 是不理想的, 因为它大大提高其热灵敏度和改变其长期的化学稳定性。
nanothermites 膜的制备由杨et al.从复杂的分层 MnO2/诺2异混合与 al 纳米粒子6。在这些材料中, 氧化物相具有非常特殊的形貌, 其中 MnO2纳米线由诺2分支覆盖。由于其特殊的结构, 氧化物不仅能捕获铝纳米粒子, 而且还能保证膜的机械阻力。MnO2/诺2/铝膜的制备过程非常简单;它包括过滤的 nanothermite 中所包含的液体中, 它已经准备, 使用滤饼作为膜。
综上所述, 科学文献中提到的唯一的 nanothermite 物体是沉积在基质、气凝胶或垫上。以固体泡沫塑料的形式制备 nanothermites 的想法为将这些高能材料集成到功能性烟火系统中开辟了新的视野。本文报道的发泡过程简单, 可以应用于任何从铝纳米制备的 nanothermite。发泡剂为正磷酸酸 (H3PO4), 一种常见的、廉价的和无毒的化学物质, 它与纳米铝反应, 使水泥 (狗4) 和气体 (h2, h2O 蒸气) 产生的孔隙度材料1。磷酸铝在高温下特别稳定, 与有机粘合剂如高能聚合物 (硝化纤维素) 相反。然而, 根据清水30提出的 "负爆炸物" 的概念, 狗4在高温下表现为对纳米 Al 的氧化剂。

<table><tbody><tr><td>Aluminum nanopowder</td><td>Intrinsiq Materials</td><td>-</td><td>nanopowder, &amp;asymp; 100 nm particle size Al QNA891</td></tr><tr><td>Tungsten(VI) oxide</td><td>Sigma-Aldrich</td><td>550086-25G</td><td>nanopowder, &amp;lt;100 nm particle size (TEM) Lot# MKBR9903V</td></tr><tr><td>Orthophosphoric Acid</td><td>Fisher Scientific</td><td>-</td><td>85% solution</td></tr><tr><td>polyethylene Pasteur pipette 3 mL</td><td>Th. Geyer</td><td>7691062</td><td>LABSOLUTE Pasteur pipettes made of polyethylene (PE) graduation 0,50 ml, Length 145 mm</td></tr><tr><td>polyethylene Pasteur pipette 1 mL</td><td>Th. Geyer</td><td>7691063</td><td>LABSOLUTE Pasteur pipettes made of polyethylene (PE) graduation 0,25 ml, Length 150 mm</td></tr><tr><td>Test tube shaker Reax Control</td><td>Heidolph</td><td>541-11000-00</td><td>Vortex mixer with strong 5 mm vibration orbit yields</td></tr></tbody></table>

nanothermite with meringue-like morphology: from loose powder to ultra-porous objects

本文所描述的协议的目的是以多孔、单片状物体的形式制备铝成分 (nanothermites)。Nanothermites 是由无机燃料和氧化剂组成的易燃材料。在 nanothermite 泡沫中, 铝是燃料, 磷酸铝和三氧化钨是氧化基。在松散粉末中观察到 nanothermites 中最高的火焰传播速度 (FPVs), 并通过球团 nanothermite 粉强烈降低 FPVs。从物理角度来看, nanothermite 松散粉末是亚稳态系统。它们的性质可以通过冲击或振动引起的无意压实或由粒子随时间的分离而改变, 这是由其组分的密度差异产生的。从粉末到物体的移动是在烟火系统中集成 nanothermites 必须克服的挑战。Nanothermite 物体必须具有高开口孔隙度和良好的机械强度。Nanothermite 泡沫符合这两个标准, 并通过分散纳米铝混合物 (Al/窝3) 在正磷酸酸中制备。铝与酸性溶液的反应使狗4 "水泥", 其中 Al 和禾3纳米粒子被嵌入。在 nanothermite 泡沫中, 磷酸铝具有粘结剂和氧化剂的双重作用。该方法可与三氧化钨配合使用, 不因制备工艺而改变。它可能被扩展到一些氧化物, 通常用于制备高性能 nanothermites。本文描述的禾3基 nanothermite 泡沫塑料对撞击和摩擦的影响特别敏感, 这使得它们比松散的铝/禾3粉末更安全。这些材料的快速燃烧在烟火点火中有着有趣的应用。它们在雷管中作为引物使用将需要在其组成中加入二次炸药。

铝基体含有结晶铝 (铝) 和磷酸铝 (狗4)。X 射线衍射证实了这些相的存在 (图 1)。此外, 重量实验表明, 该材料还包含一个晶部分, 这是无定形氧化铝。在这些材料中, 磷酸铝作为粘合剂和氧化剂的行为。狗4的氧化性能通过测量50/50 重量级的爆炸热 (3340 J/克) 来证明./重量% 纳米铝/狗4混合物在炸弹量热计1中。...

Watch this Scientific Journal Video about Nanothermite with Meringue-like Morphology: From Loose Powder to Ultra-porous Objects at JoVE.com

Nanothermite with Meringue-like Morphology: From Loose Powder to Ultra-porous Objects

本手稿描述了由正磷酸酸 (H3PO4) 与铝纳米的反应合成可燃铝矩阵。当这种反应是在三氧化钨纳米的情况下进行过量铝, 它会导致一个固体, 多孔 nanothermite 泡沫。

Nanothermite 与蛋白酥样形态学: 从松散的粉末到超多孔物体

The goal of the protocol described in this article is to prepare aluminothermic compositions (nanothermites) in the form of porous, monolithic objects. ...

nanothermite-with-meringue-like-morphology-from-loose-powder-to-ultra

Universidad de Cartagena UDEC

Research

JoVE Journal

Chemistry

7.6K 次观看.  French-German Research Institute of Saint-Louis (ISL). 本手稿描述了由正磷酸酸 (H3PO4) 与铝纳米的反应合成可燃铝矩阵。当这种反应是在三氧化钨纳米的情况下进行过量铝, 它会导致一个固体, 多孔 nanothermite 泡沫。

视频: Nanothermite with Meringue-like Morphology: From Loose Powder to Ultra-porous Objects

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

Nanomoulding of Functional Materials, a Versatile Complementary Pattern Replication Method to Nanoimprinting

We describe a nanomoulding technique which allows low-cost nanoscale patterning of functional materials, materials stacks and full devices. Nanomoulding combined with layer transfer enables the replication of arbitrary surface patterns from a master structure onto the functional material. Nanomoulding can be performed on any nanoimprinting setup and can be applied to a wide range of materials and deposition processes. In particular we demonstrate the fabrication of patterned transparent zinc oxide electrodes for light trapping applications in solar cells.

We describe a nanomoulding technique which allows low-cost nanoscale patterning of functional materials, materials stacks and full devices. Nanomoulding can be performed on any nanoimprinting setup and can be applied to a wide range of materials and deposition processes.

Nanomoulding功能材料，灵活的互补模式的复制方法，以奈米

We describe a nanomoulding technique which  allows low-cost nanoscale patterning of functional materials, materials stacks  and full devices. Nanomoulding ...

Reverse Microemulsion-mediated Synthesis of Monometallic and Bimetallic Early Transition Metal Carbide and Nitride Nanoparticles

A reverse microemulsion is used to encapsulate monometallic or bimetallic early transition metal oxide nanoparticles in microporous silica shells. The silica-encapsulated metal oxide nanoparticles are then carburized in a methane/hydrogen atmosphere at temperatures over 800 &#176;C to form silica-encapsulated early transition metal carbide nanoparticles. During the carburization process, the silica shells prevent the sintering of adjacent carbide nanoparticles while also preventing the deposition of excess surface carbon. Alternatively, the silica-encapsulated metal oxide nanoparticles can be nitridized in an ammonia atmosphere at temperatures over 800 &#176;C to form silica-encapsulated early transition metal nitride nanoparticles. By adjusting the reverse microemulsion parameters, the thickness of the silica shells, and the carburization/nitridation conditions, the transition metal carbide or nitride nanoparticles can be tuned to various sizes, compositions, and crystal phases. After carburization or nitridation, the silica shells are then removed using either a room-temperature aqueous ammonium bifluoride solution or a 0.1 to 0.5 M NaOH solution at 40-60 &#176;C. While the silica shells are dissolving, a high surface area support, such as carbon black, can be added to these solutions to obtain supported early transition metal carbide or nitride nanoparticles. If no high surface area support is added, then the nanoparticles can be stored as a nanodispersion or centrifuged to obtain a nanopowder.

A &#8220;removable ceramic coating method&#8221; is presented in visual format for the synthesis of non-sintered and metal-terminated monometallic and bimetallic early transition metal carbide and nitride nanoparticles with tunable sizes and crystal structures.

单金属和双金属前过渡金属碳化物和氮化物纳米粒子的反相微乳液介导的合成

A reverse microemulsion is used to encapsulate monometallic or bimetallic early transition metal oxide nanoparticles in microporous silica shells. The ...

化学

Synthesis and Reaction Chemistry of Nanosize Monosodium Titanate

This paper describes the synthesis and peroxide-modification of nanosize monosodium titanate (nMST), along with an ion-exchange reaction to load the material with Au(III) ions. The synthesis method was derived from a sol-gel process used to produce micron-sized monosodium titanate (MST), with several key modifications, including altering reagent concentrations, omitting a particle seed step, and introducing a non-ionic surfactant to facilitate control of particle formation and growth. The resultant nMST material exhibits spherical-shaped particle morphology with a monodisperse distribution of particle diameters in the range from 100 to 150&#160;nm. The nMST material was found to have a Brunauer-Emmett-Teller (BET) surface area of 285 m2g-1, which is more than an order of magnitude higher than the micron-sized MST. The isoelectric point of the nMST measured 3.34 pH units, which is a pH unit lower than that measured for the micron-size MST. The nMST material was found to serve as an effective ion exchanger under weakly acidic conditions for the preparation of an Au(III)-exchange nanotitanate. In addition, the formation of the corresponding peroxotitanate was demonstrated by reaction of the nMST with hydrogen peroxide.

The surfactant mediated sol-gel synthesis of nanosized monosodium titanate is described, along with preparation of the corresponding peroxide modified material. An ion-exchange reaction with Au(III) is also presented.

纳米尺寸钛酸二氢钠的合成和化学反应

This paper describes the synthesis and peroxide-modification of nanosize monosodium titanate (nMST), along with an ion-exchange reaction to load the ...

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 ...

Facile Preparation of Ultrafine Aluminum Hydroxide Particles with or without Mesoporous MCM-41 in Ambient Environments

An aqueous suspension of nanogibbsite was synthesized via the titration of aluminum aqua acid [Al(H2O)6]3+ with L-arginine to pH 4.6. Since the hydrolysis of aqueous aluminum salts is known to produce a wide array of products with a wide range of size distributions, a variety of state-of-the-art instruments (i.e., 27Al/1H NMR, FTIR, ICP-OES, TEM-EDX, XPS, XRD, and BET) were used to characterize the synthesis products and identification of byproducts. The product, which was comprised of nanoparticles (10-30 nm), was isolated using gel permeation chromatography (GPC) column technique. Fourier transform infrared (FTIR) spectroscopy and powder X-ray diffraction (PXRD) identified the purified material as the gibbsite polymorph of aluminum hydroxide. The addition of inorganic salts (e.g., NaCl) induced electrostatic destabilization of the suspension, thereby agglomerating the nanoparticles to yield Al(OH)3 precipitate with large particle sizes. By utilizing the novel synthetic method described here, Al(OH)3 was partially loaded inside the highly ordered mesoporous framework of MCM-41, with average pore dimensions of 2.7 nm, producing an aluminosilicate material with both octahedral and tetrahedral Al (Oh/Td = 1.4). The total Al content, measured using energy-dispersive X-ray spectrometry (EDX), was 11% w/w with a Si/Al molar ratio of 2.9. A comparison of bulk EDX with surface X-ray photoelectron spectroscopy (XPS) elemental analysis provided insight into the distribution of Al within the aluminosilicate material. Furthermore, a higher ratio of Si/Al was observed on the external surface (3.6) as compared to the bulk (2.9). Approximations of O/Al ratios suggest a higher concentration of Al(O)3 and Al(O)4 groups near the core and external surface, respectively. The newly developed synthesis of Al-MCM-41 yields a relatively high Al content while maintaining the integrity of the ordered silica framework and can be used for applications where hydrated or anhydrous Al2O3 nanoparticles are advantageous.

An ultrafine aluminum hydroxide nanoparticle suspension was prepared via the controlled titration of [Al(H2O)]3+ with L-arginine to pH 4.6 with and without cage-effect confinement within mesoporous channels of MCM-41.

在环境环境中制备具有或不具有介孔MCM-41的超细氢氧化铝颗粒

An aqueous suspension of nanogibbsite was synthesized via the titration of aluminum aqua acid [Al(H2O)6]3+ with L-arginine to pH 4.6. Since the hydrolysis ...

Processing of Bulk Nanocrystalline Metals at the US Army Research Laboratory

Given their potential for significant property improvements relative to their large grained counterparts, much work has been devoted to the continued development of nanocrystalline metals. Despite these efforts, the transition of these materials from the lab bench to actual applications has been blocked by the inability to produce large scale parts that retain the desired nanocrystalline microstructures. Following the development of a method proven to stabilize the nanosized grain structure to temperatures approaching that of the melting point for the given metal, the US Army Research Laboratory (ARL) has progressed to the next stage in the development of these materials - namely the production of large scale parts suitable for testing and evaluation in a range of relevant test environments. This report provides a broad overview of the ongoing efforts in the processing, characterization, and consolidation of these materials at ARL. In particular, focus is placed on the methodology used for producing the nanocrystalline metal powders, in both small and large-scale amounts, that are at the center of ongoing research efforts.

This paper provides a brief overview of the ongoing efforts at the Army Research Laboratory on the processing of bulk nanocrystalline metals with an emphasis on the methodologies used for the production of the novel metal powders.

美国陆军研究实验室散装纳米晶金属的加工

Given their potential for significant property improvements relative to their large grained counterparts, much work has been devoted to the continued ...

Surface Properties of Synthesized Nanoporous Carbon and Silica Matrices

In this work, we report the synthesis and characterization of ordered nanoporous carbon material (also called ordered mesoporous carbon material [OMC]) with a 4.6 nm pore size, and ordered silica porous matrix, SBA-15, with a 5.3 nm pore size. This work describes the surface properties of nanoporous molecular sieves, their wettability, and the melting behavior of D2O confined in the differently ordered porous materials with similar pore sizes. For this purpose, OMC and SBA-15 with highly ordered nanoporous structures are synthesized via impregnation of the silica matrix by applying a carbon precursor and by the sol-gel method, respectively. The porous structure of investigated systems is characterized by an N2 adsorption-desorption analysis at 77 K. To determine the electrochemical character of the surface of synthesized materials, potentiometric titration measurements are conducted; the obtained results for OMC shows a significant pHpzc shift toward the higher values of pH, relative to SBA-15. This suggests that investigated OMC has surface properties related to oxygen-based functional groups. To describe the surface properties of the materials, the contact angles of liquids penetrating the studied porous beds are also determined. The capillary rise method has confirmed the increased wettability of the silica walls relative to the carbon walls and an influence of the pore roughness on the fluid/wall interactions, which is much more pronounced for silica than for carbon mesopores. We have also studied the melting behavior of D2O confined in OMC and SBA-15 by applying the dielectric method. The results show that the depression of the melting temperature of D2O in the pores of OMC is about 15 K higher relative to the depression of the melting temperature in SBA-15 pores with a comparable 5 nm size. This is caused by the influence of adsorbate/adsorbent interactions of the studied matrices.

Here we report the synthesis and characterization of ordered nanoporous carbon (with a 4.6 nm pore size) and SBA-15 (with a 5.3 nm pore size). The work describes the surface and textural properties of nanoporous molecular sieves, their wettability, and the melting behavior of D2O confined in the materials.

合成纳米碳和二氧化硅矩阵的表面性能

In this work, we report the synthesis and characterization of ordered nanoporous carbon material (also called ordered mesoporous carbon material [OMC]) ...

Microscopic Visualization of Porous Nanographenes Synthesized through a Combination of Solution and On-Surface Chemistry

On-surface synthesis has recently been regarded as a promising approach for the generation of new molecular structures. It has been particularly successful in the synthesis of graphene nanoribbons, nanographenes and intrinsically reactive and instable, yet attractive species. It is based on the combination of solution chemistry aimed at preparation of appropriate molecular precursors for further ultra-high vacuum surface assisted transformations. This approach also owes its success to an incredible development of characterization techniques, such as scanning tunneling/atomic force microscopy and related methods, which allow detailed, local characterization at atomic scale. While the surface-assisted synthesis can provide molecular nanostructures with outstanding precision, down to single atoms, it suffers from basing on metallic surfaces and often limited yield. Therefore, the extension of the approach away from metals and the struggle to increase productivity seem to be significant challenges toward wider applications. Herein, we demonstrate the on-surface synthesis approach for generation of non-planar nanographenes, which are synthesized through a combination of solution chemistry and sequential surface-assisted processes, together with the detailed characterization by scanning probe microscopy methods.

<meta charset="utf8"></head><body>通过溶液和表面化学相结合合成的多孔纳米石墨烯的微观可视化

A combination of solution and surface assisted synthesis opens new directions in the atomically precise synthesis of nanostructures. Scanning tunneling microscopy (STM) supplemented by non-contact atomic force microscopy (nc-AFM) enables detailed characterization of newly designed and generated carbon-based nano-objects.