Name: activating molecules, ions, and solid particles with acoustic cavitation
Uploaded: 2014-04-11T21:30:00
Description: Watch this Scientific Journal Video about Activating Molecules, Ions, and Solid Particles with Acoustic Cavitation at JoVE.com

The authors would like to acknowledge the French ANR (grant ANR-10-BLAN-0810 NEQSON) and CEA/DEN/Marcoule.

1. Measurement&#160;of Uranium Sonoluminescence
The thermostated cylindrical sonoreactor is mounted on top of a high-frequency transducer providing 203 or 607 kHz ultrasound. Ultrasonic irradiation with low frequency ultrasound of 20 kHz is performed with a 1-cm2 titanium horn placed reproducibly on top of the reactor. The emission spectra are recorded in the range 230&#8211;800 nm using a spectrometer coupled to a liquid-nitrogen cooled CCD camera. Hydrogen in the outlet gas is measu...

<ol>
	<li>Mason, T. J., Lorimer, J. P. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Applied+Sonochemistry.+The+Uses+of+Power+Ultrasound+in+Chemistry+and+Processing.">Applied Sonochemistry. The Uses of Power Ultrasound in Chemistry and Processing.</a> Wiley-VCH Verlag GmbH. , (2002).</li><li>Suslick, 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=.">.</a> Ultrasound: Its Chemical, Physical, and Biological Effects. , (1988).</li><li>Pflieger, R., Brau, H. -. P., Nikitenko, S. I. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Sonoluminescence+from+OH(C2&#931;+)+and+OH(A2&#931;+)+Radicals+in+Water:+Evidence+for+Plasma+Formation+during+Multibubble+Cavitation.">Sonoluminescence from OH(C2&#931;+) and OH(A2&#931;+) Radicals in Water: Evidence for Plasma Formation during Multibubble Cavitation.</a> Chem. Eur. J. 16, 11801-11803 (2010).</li><li>Ndiaye, A. A., Pflieger, R., Siboulet, B., Molina, J., Dufreche, J. -. F., Nikitenko, S. I. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Nonequilibrium+Vibrational+Excitation+of+OH+Radicals+Generated+during+Multibubble+Cavitation+in+Water.">Nonequilibrium Vibrational Excitation of OH Radicals Generated during Multibubble Cavitation in Water.</a> J. Phys. Chem. A. 116, 4860-4867 (2012).</li><li>Ndiaye, A. A., Pflieger, R., Siboulet, B., Nikitenko, S. I. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+Origin+of+Isotope+Effects+in+Sonoluminescence+Spectra+of+Heavy+and+Light.">The Origin of Isotope Effects in Sonoluminescence Spectra of Heavy and Light.</a> Angew. Chem. Int. Ed. 52, 2478-2481 (2013).</li><li>Pflieger, R., Cousin, V., Barr&#233;, N., Moisy, P., Nikitenko, S. I. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Sonoluminescence+of+Uranyl+Ions+in+Aqueous+Solutions.">Sonoluminescence of Uranyl Ions in Aqueous Solutions.</a> Chem. Eur. J. 18, 410-414 (2012).</li><li>Chave, T., Navarro, N. M., Nitsche, S., Nikitenko, S. I. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Mechanism+of+Pt(IV)+Sonochemical+Reduction+in+Formic+Acid+Media+and+Pure+Water.">Mechanism of Pt(IV) Sonochemical Reduction in Formic Acid Media and Pure Water.</a> Chem. Eur. J. 18, 3879-3885 (2010).</li><li>Thompson, L. H., Doraiswamy, L. K. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Sonochemistry:+science+and+engineering.">Sonochemistry: science and engineering.</a> Ind. Eng. Chem. Res. 38, 1215-1249 (2012).</li><li>Nikitenko, S. I., Venault, L., Pflieger, R., Chave, T., Bisel, I., Moisy, P. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Potential+applications+of+sonochemistry+in+spent+nuclear+fuel+reprocessing:+a+short+review.">Potential applications of sonochemistry in spent nuclear fuel reprocessing: a short review.</a> Ultrason. Sonochem. 17, 1033-1040 (2010).</li><li>Chave, T., Den Auwer, C., Moisy, P., Nikitenko, S. I. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Sonochemical+formation+of+Pu(IV)+colloids.">Sonochemical formation of Pu(IV) colloids.</a> ATALANTE 2012 Nuclear chemistry for sustainable fuel cycles. , (2012).</li><li>Baird, C. P., Kemp, T. J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Luminescence+spectroscopy,+lifetimes+and+quenching+mechanisms+of+excited+states+of+uranyl+and+other+actinide+ions.">Luminescence spectroscopy, lifetimes and quenching mechanisms of excited states of uranyl and other actinide ions.</a> Prog. React. Kinet. 22 (2), 87-139 (1997).</li><li>Marcantonatos, M. D. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Photochemistry+and+exciplex+of+the+uranyl+ion+in+aqueous+solution.">Photochemistry and exciplex of the uranyl ion in aqueous solution.</a> J. Chem. Soc. Faraday Trans. 76, 1093-1097 (1980).</li><li>Burrows, H. D., Kemp, T. J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Photochemistry+of+uranyl+ion.">Photochemistry of uranyl ion.</a> Chem. Soc. Rev. 3, 139-165 (1974).</li><li>Kazakov, V. P., Sharipov, G. L., Sadykov, P. A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Specific+quenching+of+the+radioluminescence+from+UO22++ions+by+the+products+of+radiolysis+in+acidic+solutions.">Specific quenching of the radioluminescence from UO22+ ions by the products of radiolysis in acidic solutions.</a> High Energy Chemistry (Khimiya Vysokikh Energii. 16, 376-377 (1982).</li><li>Katz, J. J., Seaborg, G. T., Morss, L. R. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=2nd+ed.">2nd ed.</a> The Chemistry of the Actinide Elements. , (1986).</li><li>Rabinowitch, E., Belford, 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=.">.</a> Spectroscopy and Photochemistry of Uranyl Compounds. , (1964).</li><li>Mizukoshi, Y., Takagi, E., Okuno, H., Oshima, R., Maeda, Y., Nagata, Y. <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+platinum+nanoparticles+by+sonochemical+reduction+of+the+Pt(IV)+ions:+role+of+surfactants.">Preparation of platinum nanoparticles by sonochemical reduction of the Pt(IV) ions: role of surfactants.</a> Ultrason. Sonochem. 8, 1-6 (2001).</li><li>Fischer, C. H., Hart, E. J., Henglein, A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Ultrasonic+Irradiation+of+Water+in+the+Presence+of+18,18O2:+Isotope+Exchange+and+Isotopic+Distribution+of+H2O2.">Ultrasonic Irradiation of Water in the Presence of 18,18O2: Isotope Exchange and Isotopic Distribution of H2O2.</a> J. Phys. Chem. 90, 1954-1956 (1986).</li><li>Nikitenko, S. I., Martinez, P., Chave, T., Billy, I. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Sonochemical+Disproportionation+of+Carbon+Monoxide+in+Water:+Evidence+for+Treanor+Effect+during+Multibubble+Cavitation.">Sonochemical Disproportionation of Carbon Monoxide in Water: Evidence for Treanor Effect during Multibubble Cavitation.</a> Angew. Chem. Int. Ed. 48, 9529-9532 (2009).</li><li>Surendran, G., 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=From+self-assembly+of+platinum+nanoparticles+to+nanostructured+materials.">From self-assembly of platinum nanoparticles to nanostructured materials.</a> Small. 1, 964-967 (2005).</li><li>Chave, T., Grunenwald, A., Ayral, A., Lacroix-Desmazes, P., Nikitenko, S. I. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Sonochemical+deposition+of+platinum+nanoparticles+on+polymer+beads+and+their+transfer+on+the+pore+surface+of+a+silica+matrix.">Sonochemical deposition of platinum nanoparticles on polymer beads and their transfer on the pore surface of a silica matrix.</a> J. Colloid Interface Sci. 395, 81-84 (2013).</li><li>Virot, 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=Catalytic+dissolution+of+ceria+under+mild+conditions.">Catalytic dissolution of ceria under mild conditions.</a> J. Mater. Chem. 22, 14734-14740 (2012).</li><li>Virot, M., Chave, T., Nikitenko, S. I., Shchukin, D. G., Zemb, T., Moehwald, H. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Acoustic+cavitation+at+the+water-glass+interface.">Acoustic cavitation at the water-glass interface.</a> J. Phys. Chem. C. 114, 13083-13091 (2010).</li><li>Virot, M., Pflieger, R., Skorb, E. V., Ravaux, J., Zemb, T., Mohwald, H. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Crystalline+silicon+under+acoustic+cavitation:+from+mechanoluminescence+to+amorphization.">Crystalline silicon under acoustic cavitation: from mechanoluminescence to amorphization.</a> J. Phys. Chem. C. 116, 15493-15499 (2012).</li><li>Walther, C., 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=New+insights+in+the+formation+processes+of+Pu(IV)+colloids.">New insights in the formation processes of Pu(IV) colloids.</a> Radiochim. Acta. 97, 199-207 (2009).</li><li>Young, F. R. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=.">.</a> Sonoluminescence. , (2004).</li><li>Pflieger, R., Schneider, J., Siboulet, B., M&#246;hwald, H., Nikitenko, S. I. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Luminescence+of+trivalent+lanthanide+ions+excited+by+single-bubble+and+multibubble+cavitations.">Luminescence of trivalent lanthanide ions excited by single-bubble and multibubble cavitations.</a> J. Phys. Chem. B. 117, 2979-2984 (2013).</li></ol>

The most critical parameters for successful observation of sonoluminescence and sonochemistry are: 1) rigorous control of the saturating gas and the bulk temperature during sonication, 2) careful selection of ultrasonic frequency, 3) using an optimal composition of sonicated solution to prevent quenching.
The kinetics of the sonochemical reactions as well as the intensity of sonoluminescence is very sensitive to the temperature of solution submitted to ultrasound: in contrast to the kinetics o...

The use of power ultrasound in numerous industrial and research areas, such as the cleaning of solid surfaces, degassing of liquids, material sciences, environmental remediation, and medicine, has received much attention during the last decade 1. The ultrasonic treatment increases the conversion, improves the yield, and initiates the reactions in homogeneous solutions as well as in heterogeneous systems. It is generally accepted that the physical and chemical effects of ultrasonic vibrations in liquids arise from acoustic cavitation or, in other words, to the implosive collapse of microbubbles in fluids irradiated with power ultrasound 2. Violent implosion of the cavitation bubble generates transient extreme conditions in the gas phase of the bubble, which are responsible for the formation of chemically active species and sonoluminescence. Nevertheless, debate still continues over the origin of such extreme conditions. Spectroscopic analysis of the sonoluminescence helps to better understand the processes occurring during the bubble collapse. In water, saturated with noble gases, the sonoluminescence spectra are composed from OH(A2&#931;+-X2&#928;i), OH(C2S+-A2S+) bands and a broad continuum ranging from UV to NIR part of the emission spectra 3. Spectroscopic analysis of OH(A2&#931;+-X2&#928;i) emission bands revealed formation of nonequilibrium plasma during sonolysis of water 4, 5. At low ultrasonic frequency, weakly excited plasma with Brau vibrational distribution is formed. By contrast, at high-frequency ultrasound, the plasma inside collapsing bubbles exhibits Treanor behavior typical for strong vibrational excitation. The vibronic temperatures (Tv, Te) increase with ultrasonic frequency indicating more drastic intrabubble conditions at high-frequency ultrasound.
In principal, each cavitation bubble can be considered as a plasma chemical microreactor providing highly energetic processes at almost room temperature of the bulk solution. The photons and the "hot" particles produced inside the bubble enable to excite the non-volatile species in solutions thus increasing their chemical reactivity. For example, the mechanism of ultrabright sonoluminescence of uranyl ions in acidic solutions is influenced by uranium concentration: photons absorption/re-emission in diluted solutions, and excitation via collisions with "hot" particles contributes at higher uranyl concentration 6. Chemical species produced by cavitation bubbles can be used for the synthesis of metallic nanoparticles without any templates or capping agents. In pure water sparged with argon, the sonochemical reduction of Pt(IV) occurs by hydrogen issued from sonochemical water molecules splitting yielding monodispersed nanoparticles of metallic platinum 7. Sonochemical reduction is accelerated manifold in the presence of formic acid or Ar/CO gas mixture.
Many previous studies have shown the advantages of ultrasound to activate the surface of divided solids due to the mechanical effects in addition to chemical activation 8,9. Small solid particles that are much less in size than the cavitation bubbles do not perturb the symmetry of collapse. However, when a cavitation event occurs near big aggregates or near extended surface the bubble implodes asymmetrically, forming a supersonic microjet leading to the cluster disaggregating and to the solid surface erosion. Ultrasonic treatment of plutonium dioxide in pure water sparged with argon causes formation of stable nanocolloids of plutonium(IV) due to both physical and chemical effects 10.

<table border="0" cellpadding="0" cellspacing="0" width="573">
	<tbody>
		<tr height="42">
			<td height="42" style="height:42px;width:216px;">20 kHz Ultrasound Generator</td>
			<td style="width:71px;">Sonics Vibracell</td>
			<td style="width:119px;"></td>
			<td></td>
		</tr>
		<tr height="84">
			<td height="84" style="height:84px;width:216px;">Multifrequency Generator AG 1006</td>
			<td style="width:71px;">T&#38;C Power&#160; Conversion</td>
			<td style="width:119px;"></td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">Cryostat RE210&#160;</td>
			<td style="width:71px;">Lauda</td>
			<td style="width:119px;"></td>
			<td></td>
		</tr>
		<tr height="42">
			<td height="42" style="height:42px;width:216px;">Spectrometer SP 2356i</td>
			<td style="width:71px;">Roper Scientific</td>
			<td style="width:119px;"></td>
			<td></td>
		</tr>
		<tr height="42">
			<td height="42" style="height:42px;width:216px;">CCD camera SPEC10-100BR cooled with liquid nitrogen</td>
			<td style="width:71px;">Roper Scientific</td>
			<td style="width:119px;"></td>
			<td></td>
		</tr>
		<tr height="42">
			<td height="42" style="height:42px;width:216px;">Quadrupole mass-spectrometer PROLAB 300</td>
			<td style="width:71px;">Thermoscientific</td>
			<td style="width:119px;"></td>
			<td></td>
		</tr>
		<tr height="42">
			<td height="42" style="height:42px;width:216px;">Centrifuge Sigma 1-14</td>
			<td style="width:71px;">Sigma-Aldrich</td>
			<td style="width:119px;"></td>
			<td></td>
		</tr>
		<tr height="42">
			<td height="42" style="height:42px;width:216px;">H2PtCl6 6H2O</td>
			<td style="width:71px;">Sigma-Aldrich</td>
			<td style="width:119px;"></td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">Ar; Ar/CO gases</td>
			<td style="width:71px;">Air Liquid</td>
			<td style="width:119px;"></td>
			<td></td>
		</tr>
		<tr height="42">
			<td height="42" style="height:42px;width:216px;">Uranium and Plutonium compounds</td>
			<td style="width:71px;"></td>
			<td style="width:119px;"></td>
			<td>Prepared in the laboratories of Marcoule Research Center</td>
		</tr>
		<tr height="42">
			<td height="42" style="height:42px;width:216px;">Perchloric acid</td>
			<td style="width:71px;">Sigma-Aldrich</td>
			<td style="width:119px;"></td>
			<td></td>
		</tr>
		<tr height="42">
			<td height="42" style="height:42px;width:216px;">Phosphoric acid</td>
			<td style="width:71px;">Sigma-Aldrich</td>
			<td style="width:119px;"></td>
			<td></td>
		</tr>
		<tr height="42">
			<td height="42" style="height:42px;width:216px;">Formic acid</td>
			<td style="width:71px;">Sigma-Aldrich</td>
			<td style="width:119px;"></td>
			<td></td>
		</tr>
	</tbody>
</table>

activating molecules, ions, and solid particles with acoustic cavitation

The chemical and physical effects of ultrasound arise not from a direct interaction of molecules with sound waves, but rather from the acoustic cavitation: the nucleation, growth, and implosive collapse of microbubbles in liquids submitted to power ultrasound. The violent implosion of bubbles leads to the formation of chemically reactive species and to the emission of light, named sonoluminescence. In this manuscript, we describe the techniques allowing study of extreme intrabubble conditions and chemical reactivity of acoustic cavitation in solutions. The analysis of sonoluminescence spectra of water sparged with noble gases provides evidence for nonequilibrium plasma formation. The photons and the "hot" particles generated by cavitation bubbles enable to excite the non-volatile species in solutions increasing their chemical reactivity. For example the mechanism of ultrabright sonoluminescence of uranyl ions in acidic solutions varies with uranium concentration: sonophotoluminescence dominates in diluted solutions, and collisional excitation contributes at higher uranium concentration. Secondary sonochemical products may arise from chemically active species that are formed inside the bubble, but then diffuse into the liquid phase and react with solution precursors to form a variety of products. For instance, the sonochemical reduction of Pt(IV) in pure water provides an innovative synthetic route for monodispersed nanoparticles of metallic platinum without any templates or capping agents. Many studies reveal the advantages of ultrasound to activate the divided solids. In general, the mechanical effects of ultrasound strongly contribute in heterogeneous systems in addition to chemical effects. In particular, the sonolysis of PuO2 powder in pure water yields stable colloids of plutonium due to both effects.

Uranyl ion sonoluminescence is extremely weak in HClO4 solutions: though typical light absorption by UO22+ ions is observed below 500 nm, emission lines from excited (UO22+)* (centered at 512 nm and 537 nm) are hardly seen (Figure 1). The SL of UO22+ is quenched. This quenching can be attributed to reduction of the excited uranyl ion by a coordinated water molecule 11-13:
(...

Watch this Scientific Journal Video about Activating Molecules, Ions, and Solid Particles with Acoustic Cavitation at JoVE.com

Activating Molecules, Ions, and Solid Particles with Acoustic Cavitation

Acoustic cavitation in liquids submitted to power ultrasound creates transient extreme conditions inside the collapsing bubbles, which are the origin of unusual chemical reactivity and light emission, known as sonoluminescence. In the presence of noble gases, nonequilibrium plasma is formed. The "hot" particles and the photons generated by collapsing bubbles are able to excite species in solution.

The chemical and physical effects of ultrasound arise not from a direct interaction of molecules with sound waves, but rather from the acoustic ...

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Chemistry

Origami Inspired Self-assembly of Patterned and Reconfigurable Particles

There are numerous techniques such as photolithography, electron-beam lithography and soft-lithography that can be used to precisely pattern two dimensional (2D) structures. These technologies are mature, offer high precision and many of them can be implemented in a high-throughput manner. We leverage the advantages of planar lithography and combine them with self-folding methods1-20 wherein physical forces derived from surface tension or residual stress, are used to curve or fold planar structures into three dimensional (3D) structures. In doing so, we make it possible to mass produce precisely patterned static and reconfigurable particles that are challenging to synthesize.
In this paper, we detail visualized experimental protocols to create patterned particles, notably, (a) permanently bonded, hollow, polyhedra that self-assemble and self-seal due to the minimization of surface energy of liquefied hinges21-23 and (b) grippers that self-fold due to residual stress powered hinges24,25. The specific protocol described can be used to create particles with overall sizes ranging from the micrometer to the centimeter length scales. Further, arbitrary patterns can be defined on the surfaces of the particles of importance in colloidal science, electronics, optics and medicine. More generally, the concept of self-assembling mechanically rigid particles with self-sealing hinges is applicable, with some process modifications, to the creation of particles at even smaller, 100 nm length scales22, 26 and with a range of materials including metals21, semiconductors9 and polymers27. With respect to residual stress powered actuation of reconfigurable grasping devices, our specific protocol utilizes chromium hinges of relevance to devices with sizes ranging from 100 &mu;m to 2.5 mm. However, more generally, the concept of such tether-free residual stress powered actuation can be used with alternate high-stress materials such as heteroepitaxially deposited semiconductor films5,7 to possibly create even smaller nanoscale grasping devices.

We describe experimental details of the synthesis of patterned and reconfigurable particles from two dimensional (2D) precursors. This methodology can be used to create particles in a variety of shapes including polyhedra and grasping devices at length scales ranging from the micro to centimeter scale.

There are numerous techniques such as photolithography, electron-beam lithography and soft-lithography that can be used to precisely pattern two ...

Dynamic Electrochemical Measurement of Chloride Ions

This protocol describes the dynamic measurement of chloride ions using the transition time of a silver silver chloride (Ag/AgCl) electrode. Silver silver chloride electrode is used extensively for potentiometric measurement of chloride ions concentration in electrolyte. In this measurement, long-term and continuous monitoring is limited due to the inherent drift and the requirement of a stable reference electrode. We utilized the chronopotentiometric approach to minimize drift and avoid the use of a conventional reference electrode. A galvanostatic pulse is applied to an Ag/AgCl electrode which initiates a faradic reaction depleting the Cl&#713; ions near the electrode surface. The transition time, which is the time to completely deplete the ions near the electrode surface, is a function of the ion concentration, given by the Nernst equation. The square root of the transition time is in linear relation to the chloride ion concentration. Drift of the response over two weeks is negligible (59 &#181;M/day) when measuring 1 mM [Cl&#713;]using a current pulse of 10 Am-2. This is a dynamic measurement where the moment of transition time determines the response and thus is independent of the absolute potential. Any metal wire can be used as a pseudo-reference electrode, making this approach feasible for long-term measurement inside concrete structures.

Dynamic measurement of chloride ions is presented. Transition time of an Ag/AgCl electrode, during a chronopotentiometric technique, can give the concentration of chloride ions in electrolyte. This method does not require a stable conventional reference electrode.

This protocol describes the dynamic measurement of chloride ions using the transition time of a silver silver chloride (Ag/AgCl) electrode. Silver silver ...

X-ray Powder Diffraction in Conservation Science: Towards Routine Crystal Structure Determination of Corrosion Products on Heritage Art Objects

The crystal structure determination and refinement process of corrosion products on historic art objects using laboratory high-resolution X-ray powder diffraction (XRPD) is presented in detail via two case studies.
The first material under investigation was sodium copper formate hydroxide oxide hydrate, Cu4Na4O(HCOO)8(OH)2&#8729;4H2O (sample 1) which forms on soda glass/copper alloy composite historic objects (e.g., enamels) in museum collections, exposed to formaldehyde and formic acid emitted from wooden storage cabinets, adhesives, etc. This degradation phenomenon has recently been characterized as &#34;glass induced metal corrosion&#34;.
For the second case study, thecotrichite, Ca3(CH3COO)3Cl(NO3)2&#8729;6H2O (sample 2), was chosen, which is an efflorescent salt forming needlelike crystallites on tiles and limestone objects which are stored in wooden cabinets and display cases. In this case, the wood acts as source for acetic acid which reacts with soluble chloride and nitrate salts from the artifact or its environment.
The knowledge of the geometrical structure helps conservation science to better understand production and decay reactions and to allow for full quantitative analysis in the frequent case of mixtures.

Modern high resolution X-ray powder diffraction (XRPD) in the laboratory is used as an efficient tool to determine crystal structures of long-known corrosion products on historic objects.

The crystal structure determination and refinement process of corrosion products on historic art objects using laboratory high-resolution X-ray powder ...

Measurement of Particle Size Distribution in Turbid Solutions by Dynamic Light Scattering Microscopy

A protocol for measuring polydispersity of concentrated polymer solutions using dynamic light scattering is described. Dynamic light scattering is a technique used to measure the size distribution of polymer solutions or colloidal particles. Although this technique is widely used for the assessment of polymer solutions, it is difficult to measure the particle size in concentrated solutions due to the multiple scattering effect or strong light absorption. Therefore, the concentrated solutions should be diluted before measurement. Implementation of the confocal optical component in a dynamic light scattering microscope1 helps to overcome this barrier. Using such a microscopic system, both transparent and turbid systems can be analyzed under the same experimental setup without a dilution. As a representative example, a size distribution measurement of a temperature-responsive polymer solution was performed. The sizes of the polymer chains in an aqueous solution were several tens of nanometers at a temperature below the lower critical solution temperature (LCST). In contrast, the sizes increased to more than 1.0 &#181;m when above the LCST. This result is consistent with the observation that the solution turned turbid above the LCST.

A protocol for the direct measurement of particle size distribution in concentrated solutions using dynamic light scattering microscopy is presented.

A protocol for measuring polydispersity of concentrated polymer solutions using dynamic light scattering is described. Dynamic light scattering is a ...

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.

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 ...

Preparation of Stable Bicyclic Aziridinium Ions and Their Ring-Opening for the Synthesis of Azaheterocycles

Bicyclic aziridinium ions were generated by the removal of an appropriate leaving group through internal nucleophilic attack by nitrogen atom in the aziridine ring. The utility of bicyclic aziridinium ions, specifically 1-azoniabicyclo[3.1.0]hexane and 1-azoniabicyclo[4.1.0]heptane tosylate highlighted in the aziridine ring openings by the nucleophile with the release of the ring strain to yield the corresponding ring-expanded azaheterocycles such as pyrrolidine, piperidine and azepane with diverse substituents on the ring in regio- and stereospecific manner. Herein, we report a simple and convenient method for the preparation of the stable 1-azabicyclo[4.1.0]heptane tosylate followed by selective ring opening via a nucleophilic attack either at the bridge or at the bridgehead carbon to yield piperidine and azepane rings, respectively. This synthetic strategy allowed us to prepare biologically active natural products containing piperidine and azepane motif including sedamine, allosedamine, fagomine and balanol in highly efficient manner.

Bicyclic aziridinium ions such as 1-azoniabicyclo[4.1.0]heptane tosylate were generated from 2-[4-tolenesulfonyloxybutyl]aziridine, which was utilized for the preparation of substituted piperidines and azepanes via regio- and stereospecific ring-expansion with various nucleophiles. This highly efficient protocol allowed us to prepare diverse azaheterocycles including natural products such as fagomine, febrifugine analogue and balanol.

Bicyclic aziridinium ions were generated by the removal of an appropriate leaving group through internal nucleophilic attack by nitrogen atom in the ...

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.

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

Solid-phase Synthesis of [4.4] Spirocyclic Oximes

A convenient synthetic route for spirocyclic heterocycles is well sought after due to the molecule&#39;s potential use in biological systems. By means of solid-phase synthesis, regenerating Michael (REM) linker strategies, and 1,3-dipolar cycloaddition, a library of structurally similar heterocycles, both with and without a spirocyclic center, can be constructed. The main advantages of the solid-support synthesis are as follows: first, each reaction step can be driven to completion using a large excess of reagents resulting in high yields; next, the use of commercially available starting materials and reagents keep the costs low; finally, the reaction steps are easy to purify via simple filtration. The REM linker strategy is attractive because of its recyclability and traceless nature. Once a reaction scheme is completed, the linker can be reused multiple times. In a typical solid-phase synthesis, the product contains either a part of or the whole linker, which can prove undesirable. The REM linker is &#34;traceless&#34; and the point of attachment between the product and the polymer is indistinguishable. The high diastereoselectivity of the intramolecular 1,3-dipolar cycloaddition is well documented. Limited by the insolubility of the solid support, the reaction progression can only be monitored by a change in the functional groups (if any) via infrared (IR) spectroscopy. Thus, the structural identification of intermediates cannot be characterized by conventional nuclear magnetic resonance (NMR) spectroscopy. Other limitations to this method stem from the compatibilities of the polymer/linker to the desired chemical reaction scheme. Herein we report a protocol that allows for the convenient production of spirocyclic heterocycles that, with simple modifications, can be automated with high-throughput techniques.

Here we present a protocol to demonstrate an efficient method for the synthesis of spirocyclic heterocycles. The five-step process utilizes solid-phase synthesis and regenerating Michael linker strategies. Generally difficult to synthesize, we present a customizable method for the synthesis of spirocyclic molecules otherwise inaccessible to other modern approaches.

A convenient synthetic route for spirocyclic heterocycles is well sought after due to the molecule&#39;s potential use in biological systems. By means of ...

Stable DNA Motifs, 1D and 2D Nanostructures Constructed from Small Circular DNA Molecules

This article presents a detailed protocol for synthesis of small circular DNA molecules, annealing of circular DNA motifs, and construction of 1D and 2D DNA nanostructures. Over decades, the rapid development of DNA nanotechnology is attributed to the use of linear DNAs as the source materials. For example, the DAO (double crossover, antiparallel, odd half-turns) tile is well-known as a building block for construction of 2D DNA lattices; the core structure of DAO is made from two linear single-stranded (ss) oligonucleotides, like two ropes making a right hand granny&#160;knot. Herein, a new type of DNA tiles called cDAO (coupled DAO) are built using a small circular ss-DNA of c64nt or c84nt (circular 64 or 84 nucleotides) as the scaffold strand and several linear ss-DNAs as the staple strands. Perfect 1D and 2D nanostructures are assembled from cDAO tiles: infinite nanowires, nanospirals, nanotubes, nanoribbons; and finite nano-rectangles. Detailed protocols are described: 1) preparation by T4 ligase and purification by denaturing PAGE (polyacrylamide gel electrophoresis) of small circular oligonucleotides, 2) annealing of stable circular tiles, followed by native PAGE analysis, 3) assembling of infinite 1D nanowires, nanorings, nanospirals, infinite 2D lattices of nanotubes and nanoribbons, and finite 2D nano-rectangles, followed by AFM (Atomic Force Microscopy) imaging. The method is simple, robust, and affordable for most labs.

This article presents a detailed protocol for T4 ligation and denaturing PAGE purification of small circular DNA molecules, annealing and native PAGE analysis of circular tiles, assembling and AFM imaging of 1D and 2D DNA nanostructures, as well as agarose gel electrophoresis and centrifugation purification of finite DNA nanostructures.

This article presents a detailed protocol for synthesis of small circular DNA molecules, annealing of circular DNA motifs, and construction of 1D and 2D ...

Accumulation and Analysis of Cuprous Ions in a Copper Sulfate Plating Solution

Knowledge of the behavior of cuprous ions (monovalent copper ion: Cu(I)) in a copper sulfate plating bath is important for improving the plating process. We successfully developed a method to quantitatively and easily measure Cu(I) in a plating solution and used it for evaluation of the solution. In this paper, a quantitative absorption spectrum measurement and a time-resolved injection measurement of Cu(I) concentrations by a color reaction are described. This procedure is effective as a method to reproduce and elucidate the phenomenon occurring in the plating bath in the laboratory. First, the formation and accumulation process of Cu(I) in solution by electrolysis of a plating solution is shown. The amount of Cu(I) in the solution is increased by electrolysis at higher current values &#8203;&#8203;than the usual plating process. For the determination of Cu(I), BCS (bathocuproinedisulfonic acid, disodium salt), a reagent that selectively reacts with Cu(I), is used. The concentration of Cu(I) can be calculated from the absorbance of the Cu(I)-BCS complex. Next, the time measurement of the color reaction is described. The color reaction curve of Cu(I) and BCS measured by the injection method can be decomposed into an instantaneous component and a delay component. By analysis of these components, the holding structure of Cu(I) can be clarified, and this information is important when predicting the quality of the plating film to be produced. This method is used to facilitate the evaluation of the plating bath in the production line.

Here, accumulation of cuprous ions in a copper sulfate plating solution in a model experiment and an analysis based on quantitative measurements are described. This experiment reproduces the accumulation process of cuprous ions in the plating bath.

Knowledge of the behavior of cuprous ions (monovalent copper ion: Cu(I)) in a copper sulfate plating bath is important for improving the plating process. ...