Name: liquid-cell transmission electron microscopy for tracking self-assembly of nanoparticles
Uploaded: 2017-10-16T13:00:00
Description: Watch this Scientific Journal Video about Liquid-cell Transmission Electron Microscopy for Tracking Self-assembly of Nanoparticles at JoVE.com

We thank Prof. A. Paul Alivisatos at the University of California, Berkeley and Prof. Taeghwan Hyeon at Seoul National University for the helpful discussion. This work was supported by IBS-R006-D1. W.C.L. gratefully acknowledges support from the research fund of Hanyang University (HY-2015-N).

1. Synthesis of Nanoparticles
<ol>
	<li>Synthesis of platinum nanoparticles
	<ol>
		<li>Combine 17.75 mg of ammonium hexachloroplatinate(IV) ((NH4)2Pt(IV)Cl6), 3.72 mg of ammonium tetrachloroplatinate(II) ((NH4)2Pt(II)Cl4), 115.5 mg of tetramethylammonium bromide, 109 mg of poly(vinylpyrrolidone) (MW: 29,000), and 10 mL of ethylene glycol with a stir bar in a 100 mL 3-neck round bottom flask equipped with a rubber septum.</li>
		<li>Equi...

<ol>
	<li>Shevchenko, E. V., Talapin, D. V., Kotov, N. A., O'Brien, S., Murray, C. B. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Structural+Diversity+in+Binary+Nanoparticle+Superlattices.">Structural Diversity in Binary Nanoparticle Superlattices.</a> Nature. 439, 55-59 (2006).</li><li>Talapin, D. V., 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=Quasicrystalline+Order+in+Self-Assembled+Binary+Nanoparticle+Superlattices.">Quasicrystalline Order in Self-Assembled Binary Nanoparticle Superlattices.</a> Nature. 461, 964-967 (2009).</li><li>Evers, W. H., Friedrich, H., Filion, L., Dijkstra, M., Vanmaekelbergh, D. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Observation+of+a+Ternary+Nanocrystal+Superlattice+and+Its+Structural+Characterization+by+Electron+Tomography.">Observation of a Ternary Nanocrystal Superlattice and Its Structural Characterization by Electron Tomography.</a> Angew. Chem., Int. Ed. 48, 9655-9657 (2009).</li><li>Maillard, M., Motte, L., Pileni, M. P. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Rings+and+Hexagons+Made+of+Nanocrystals.">Rings and Hexagons Made of Nanocrystals.</a> Adv. Mater. 13, 200-204 (2001).</li><li>Sztrum, C. G., Rabani, E. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Out-of-Equilibrium+Self-Assembly+of+Binary+Mixtures+of+Nanoparticles.">Out-of-Equilibrium Self-Assembly of Binary Mixtures of Nanoparticles.</a> Adv. Mater. 18, 565-571 (2006).</li><li>Han, W., Lin, Z. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Learning+From+&amp;#34;coffee+Rings&amp;#34;:+Ordered+Structures+Enabled+by+Controlled+Evaporative+Self-Assembly.">Learning From &amp;#34;coffee Rings&amp;#34;: Ordered Structures Enabled by Controlled Evaporative Self-Assembly.</a> Angew. Chem., Int. Ed. 51, 1534-1546 (2012).</li><li>Bigioni, T. 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=Kinetically+Driven+Self+Assembly+of+Highly+Ordered+Nanoparticle+Monolayers.">Kinetically Driven Self Assembly of Highly Ordered Nanoparticle Monolayers.</a> Nat. Mater. 5, 265-270 (2006).</li><li>Govor, L. V., Reiter, G., Parisi, J., Bauer, G. H. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Self-Assembled+Nanoparticle+Deposits+Formed+at+the+Contact+Line+of+Evaporating+Micrometer-Size+Droplets.">Self-Assembled Nanoparticle Deposits Formed at the Contact Line of Evaporating Micrometer-Size Droplets.</a> Phys. Rev. E. 69, 61609 (2004).</li><li>Kletenik-Edelman, O., 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=Drying-Mediated+Hierarchical+Self-Assembly+of+Nanoparticles:+A+Dynamical+Coarse-Grained+Approach.">Drying-Mediated Hierarchical Self-Assembly of Nanoparticles: A Dynamical Coarse-Grained Approach.</a> J. Phys. Chem. C. 112, 4498-4506 (2008).</li><li>Kletenik-Edelman, O., Sztrum-Vartash, C. G., Rabani, E. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Coarse-Grained+Lattice+Models+for+Drying-Mediated+Self-Assembly+of+Nanoparticles.">Coarse-Grained Lattice Models for Drying-Mediated Self-Assembly of Nanoparticles.</a> J. Mater. Chem. 19, 2872-2876 (2009).</li><li>Rabani, E., Reichman, D. R., Geissler, P. L., Brus, L. E. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Drying-mediated+self-assembly+of+nanoparticles.">Drying-mediated self-assembly of nanoparticles.</a> Nature. 426, 271-274 (2003).</li><li>Loubat, A., 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=Growth+and+Self-Assembly+of+Ultrathin+Au+Nanowires+into+Expanded+Hexagonal+Superlattice+Studied+by+in+Situ+SAXS.">Growth and Self-Assembly of Ultrathin Au Nanowires into Expanded Hexagonal Superlattice Studied by in Situ SAXS.</a> Langmuir. 30, 4005-4012 (2014).</li><li>Connolly, S., Fullam, S., Korgel, B., Fitzmaurice, D. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Time-Resolved+Small-Angle+X-Ray+Scattering+Studies+of+Nanocrystal+Superlattice+Self-Assembly.">Time-Resolved Small-Angle X-Ray Scattering Studies of Nanocrystal Superlattice Self-Assembly.</a> J. Am. Chem. Soc. 120, 2969-2970 (1998).</li><li>Lu, C., Akey, A. J., Dahlman, C. J., Zhang, D., Herman, I. P. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Resolving+the+Growth+of+3D+Colloidal+Nanoparticle+Superlattices+by+Real-Time+Small-Angle+X-Ray+Scattering.">Resolving the Growth of 3D Colloidal Nanoparticle Superlattices by Real-Time Small-Angle X-Ray Scattering.</a> J. Am. Chem. Soc. 134, 18732-18738 (2012).</li><li>Zheng, H., Claridge, S. A., Minor, A. M., Alivisatos, A. P., Dahmen, U. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Nanocrystal+Diffusion+in+a+Liquid+Thin+Film+Observed+by+in+Situ+Transmission+Electron+Microscopy.">Nanocrystal Diffusion in a Liquid Thin Film Observed by in Situ Transmission Electron Microscopy.</a> Nano Lett. 9, 2460-2465 (2009).</li><li>Jungjohann, K. L., Bliznakov, S., Sutter, P. W., Stach, E. A., Sutter, E. A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=In+Situ+Liquid+Cell+Electron+Microscopy+of+the+Solution+Growth+of+Au-Pd+Core-Shell+Nanostructures.">In Situ Liquid Cell Electron Microscopy of the Solution Growth of Au-Pd Core-Shell Nanostructures.</a> Nano Lett. 13, 2964-2970 (2013).</li><li>Yuk, J. 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=High-Resolution+EM+of+Colloidal+Nanocrystal+Growth+Using+Graphene+Liquid+Cells.">High-Resolution EM of Colloidal Nanocrystal Growth Using Graphene Liquid Cells.</a> Science. 336, 61-64 (2012).</li><li>Park, J., 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=Direct+Observation+of+Nanoparticle+Superlattice+Formation+by+Using+Liquid+Cell+Transmission+Electron+Microscopy.">Direct Observation of Nanoparticle Superlattice Formation by Using Liquid Cell Transmission Electron Microscopy.</a> ACS Nano. 6, 2078-2085 (2012).</li><li>Lee, W. C., Kim, B. H., Choi, S., Takeuchi, S., Park, J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Liquid+Cell+Electron+Microscopy+of+Nanoparticle+Self-Assembly+Driven+by+Solvent+Drying.">Liquid Cell Electron Microscopy of Nanoparticle Self-Assembly Driven by Solvent Drying.</a> J. Phys. Chem. Lett. 8, 647-654 (2017).</li><li>Park, J., 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=3D+Structure+of+Individual+Nanocrystals+in+Solution+by+Electron+Microscopy.">3D Structure of Individual Nanocrystals in Solution by Electron Microscopy.</a> Science. 349, 290-295 (2015).</li><li>Chee, S. W., Baraissov, Z., Loh, N. D., Matsudaira, P. T., Mirsaidov, U. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Desorption-Mediated+Motion+of+Nanoparticles+at+the+Liquid-Solid+Interface.">Desorption-Mediated Motion of Nanoparticles at the Liquid-Solid Interface.</a> J. Phys. Chem. C. 120, 20462-20470 (2016).</li><li>Liu, Y., Lin, X. -. M., Sun, Y., Rajh, T. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=In+Situ+Visualization+of+Self-Assembly+of+Charged+Gold+Nanoparticles.">In Situ Visualization of Self-Assembly of Charged Gold Nanoparticles.</a> J. Am. Chem. Soc. 135, 3764-3767 (2013).</li><li>Verch, A., Pfaff, M., de Jonge, N. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Exceptionally+Slow+Movement+of+Gold+Nanoparticles+at+a+Solid/Liquid+Interface+Investigated+by+Scanning+Transmission+Electron+Microscopy.">Exceptionally Slow Movement of Gold Nanoparticles at a Solid/Liquid Interface Investigated by Scanning Transmission Electron Microscopy.</a> Langmuir. 31, 6956-6964 (2015).</li><li>Sutter, E., 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=In+Situ+Microscopy+of+the+Self-Assembly+of+Branched+Nanocrystals+in+Solution.">In Situ Microscopy of the Self-Assembly of Branched Nanocrystals in Solution.</a> Nat. Commun. 7, 11213 (2016).</li><li>Niu, K. -. Y., Liao, H. -. G., Zheng, H. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Revealing+Dynamic+Processes+of+Materials+in+Liquid+Using+Transmission+Electron+Microscopy.">Revealing Dynamic Processes of Materials in Liquid Using Transmission Electron Microscopy.</a> J. Vis. Exp. (70), e50122 (2012).</li><li>Hermannsd&#246;rfer, J., de Jonge, N. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Studying+Dynamic+Processes+of+Nano-sized+Objects+in+Liquid+using+Scanning+Transmission+Electron+Microscopy.">Studying Dynamic Processes of Nano-sized Objects in Liquid using Scanning Transmission Electron Microscopy.</a> J. Vis. Exp. (120), e54943 (2017).</li><li>Tsung, C. K., 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=Sub-10+nm+Platinum+Nanocrystals+with+Size+and+Shape+Control:+Catalytic+Study+for+Ethylene+and+Pyrrole+Hydrogenation.">Sub-10 nm Platinum Nanocrystals with Size and Shape Control: Catalytic Study for Ethylene and Pyrrole Hydrogenation.</a> J. Am. Chem. Soc. 131, 5816-5822 (2009).</li><li>Cho, K. S., Talapin, D. V., Gaschler, W., Murray, C. B. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Designing+PbSe+Nanowires+and+Nanorings+through+Oriented+Attachment+of+Nanoparticles.">Designing PbSe Nanowires and Nanorings through Oriented Attachment of Nanoparticles.</a> J. Am. Chem. Soc. 127, 7140-7147 (2005).</li><li>Manthiram, K., Beberwyck, B. J., Talapin, D. V., Alivisatos, A. P. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Seeded+Synthesis+of+CdSe/CdS+Rod+and+Tetrapod+Nanocrystals.">Seeded Synthesis of CdSe/CdS Rod and Tetrapod Nanocrystals.</a> J. Vis. Exp. (82), e50731 (2013).</li><li>Woehl, T. J., 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=Experimental+Procedures+to+Mitigate+Electron+Beam+Induced+Artifacts+During+in+situ+Fluid+Imaging+of+Nanomaterials.">Experimental Procedures to Mitigate Electron Beam Induced Artifacts During in situ Fluid Imaging of Nanomaterials.</a> Ultramicroscopy. 127, 53-63 (2013).</li><li>Shin, D., 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=Growth+Dynamics+and+Gas+Transport+Mechanism+of+Nanobubbles+in+Graphene+Liquid+Cells.">Growth Dynamics and Gas Transport Mechanism of Nanobubbles in Graphene Liquid Cells.</a> Nat. Commun. 6, 6068 (2015).</li></ol>

Platinum nanoparticles with a size of 7 nm were synthesized via the reduction of ammonium hexachloroplatinate (IV) and ammonium tetrachloroplatinate (II) using poly (vinylpyrrolidone) (PVP) as a ligand and ethylene glycol as a solvent and a reducing agent27. A ligand-exchange reaction with oleylamine was performed to disperse the particles in a hydrophobic solvent. Lead selenide nanoparticles were synthesized via the thermal decomposition of lead-oleate complexes using TOP-Se as a selenium source<...

The self-assembly of colloidal nanoparticles is of interest because it provides an opportunity to access collective physical properties of individual nanoparticles11. One of the most effective methods of self-assembly used in practical device-scale applications is self-organization of nanoparticles on a substrate through evaporation of a volatile solvent6,7,8,9,10,11. This solvent evaporation method is a nonequilibrium process, which is largely influenced by kinetic factors such as evaporation rate and changes in nanoparticle-substrate interactions. However, since it is difficult to estimate and control the kinetic factors, the mechanistic understanding of nanoparticle self-assembly by solvent evaporation is not fully mature. Although in situ X-ray scattering studies have provided ensemble-averaged information of the nonequilibrium nanoparticle self-assembly process12,13,14, this technique cannot determine the motion of individual nanoparticles, and their association with the overall trajectory cannot be easily accessed.
Liquid-cell TEM is an emerging tool for tracking the trajectory of individual nanoparticles, enabling us to understand the inhomogeneity of nanoparticle motions and their contribution to ensemble behaviors15,16,17,18,19,20,21,22,23,24,25,26. We have previously used liquid-cell TEM to track the motion of individual nanoparticles during solvent evaporation, showing that the movement of the solvent boundary is a major driving force for inducing nanoparticle self-assembly on a substrate18,19. Herein, we introduce experiments where we can observe the process of nanoparticle self-assembly using liquid-cell TEM. First, we provide protocols for the synthesis of platinum and lead selenide nanoparticles, before introducing the fabrication procedures of liquid-cells for TEM and how to load nanoparticles into the liquid-cell. As representative results, we show snapshot images from TEM movies of nanoparticle self-assembly driven by solvent drying. By tracking individual particles in these movies, we can understand the detailed mechanisms of solvent-drying-mediated self-assembly at a single nanoparticle level. During self-assembly, the platinum nanoparticles on the silicon nitride window mainly follow the movement of the evaporating solvent front because of the strong capillary forces acting on the thin solvent layer. Similar phenomena were also observed for other nanoparticles (lead selenide) and substrates (silicon), indicating that the capillary force of the solvent front is an important factor in particle migration near a substrate.

<table>
	<tbody>
		<tr>
			<td>ammonium hexachloroplatinate (IV)</td>
			<td>Sigma-Aldrich</td>
			<td>204021</td>
			<td></td>
		</tr>
		<tr>
			<td>ammonium tetrachloroplatinate (II)</td>
			<td>Sigma-Aldrich</td>
			<td>206105</td>
			<td></td>
		</tr>
		<tr>
			<td>tetramethylammonium bromide, 98%</td>
			<td>Sigma-Aldrich</td>
			<td>195758</td>
			<td></td>
		</tr>
		<tr>
			<td>poly(vinylpyrrolidone) powder</td>
			<td>Sigma-Aldrich</td>
			<td>234257</td>
			<td>Mw ~29,000</td>
		</tr>
		<tr>
			<td>ethylene glycol, anhydrous, 99.8%</td>
			<td>Sigma-Aldrich</td>
			<td>324558</td>
			<td></td>
		</tr>
		<tr>
			<td>n-hexane, anhydrous, 95%</td>
			<td>Samchun Chem.</td>
			<td>H0114</td>
			<td></td>
		</tr>
		<tr>
			<td>ethanol, anhydrous, 99.5%</td>
			<td>Sigma-Aldrich</td>
			<td>459836</td>
			<td></td>
		</tr>
		<tr>
			<td>oleylamine, 70%</td>
			<td>Sigma-Aldrich</td>
			<td>O7805</td>
			<td>Technical grade</td>
		</tr>
		<tr>
			<td>lead(II) acetate trihydrate, 99.99%</td>
			<td>Sigma-Aldrich</td>
			<td>467863</td>
			<td></td>
		</tr>
		<tr>
			<td>oleic acid, 90%</td>
			<td>Sigma-Aldrich</td>
			<td>364525</td>
			<td>Technical grade</td>
		</tr>
		<tr>
			<td>diphenyl ether, 99%</td>
			<td>Sigma-Aldrich</td>
			<td>P24101</td>
			<td>ReagentPlus</td>
		</tr>
		<tr>
			<td>selenium powder, 99.99%</td>
			<td>Sigma-Aldrich</td>
			<td>229865</td>
			<td></td>
		</tr>
		<tr>
			<td>tri-n-octylphosphine, 97%</td>
			<td>Strem</td>
			<td>15-6655</td>
			<td>Air sensistive</td>
		</tr>
		<tr>
			<td>Toluene, anhydrous, 99.9%</td>
			<td>Samchun Chem.</td>
			<td>T2419</td>
			<td></td>
		</tr>
		<tr>
			<td>acetone 99.8%</td>
			<td>Daejung Chem.</td>
			<td>1009-2304</td>
			<td></td>
		</tr>
		<tr>
			<td>potassium hydroxide, 95%</td>
			<td>Samchun Chem.</td>
			<td>P0925</td>
			<td></td>
		</tr>
		<tr>
			<td>p-type silicon-on-insulator wafers</td>
			<td>Soitec</td>
			<td>Power-SOI</td>
			<td>for liquid cells with silicon windows</td>
		</tr>
		<tr>
			<td>tetramethylammonium hydroxide, 25% in H2O</td>
			<td>J.T.Baker</td>
			<td>02-002-109</td>
			<td></td>
		</tr>
		<tr>
			<td>AZ 5214 E</td>
			<td>AZ Electronic Materials</td>
			<td>AZ 5214 E</td>
			<td>Positive photorest</td>
		</tr>
		<tr>
			<td>AZ-327</td>
			<td>AZ Electronic Materials</td>
			<td>AZ-327</td>
			<td>AZ 5214 develper</td>
		</tr>
		<tr>
			<td>indium pellets 99.98-99.99%</td>
			<td>Kurt J. Lesker Company</td>
			<td>EVMIN40EXEB</td>
			<td>thermal evaporator target</td>
		</tr>
		<tr>
			<td>1,2-dichlorobenzene, &#62;99%</td>
			<td>TCI</td>
			<td>D1116</td>
			<td></td>
		</tr>
		<tr>
			<td>pentadecane, &#62;99%</td>
			<td>Sigma-Aldrich</td>
			<td>P3406</td>
			<td></td>
		</tr>
		<tr>
			<td>buffered oxide etch 7:1</td>
			<td>microchemicals</td>
			<td>BOE 7-1 VLSI</td>
			<td></td>
		</tr>
		<tr>
			<td>phosphoric acid, 85%</td>
			<td>Samchun Chem.</td>
			<td>P0449</td>
			<td></td>
		</tr>
	</tbody>
</table>

liquid-cell transmission electron microscopy for tracking self-assembly of nanoparticles

Drying a nanoparticle dispersion is a versatile way to create self-assembled structures of nanoparticles, but the mechanism of this process is not fully understood. We have traced the trajectories of individual nanoparticles using liquid-cell transmission electron microscopy (TEM) to investigate the mechanism of the assembly process. Herein, we present the protocols used for liquid-cell TEM studies of the self-assembly mechanism. First, we introduce the detailed synthetic protocols used to produce uniformly sized platinum and lead selenide nanoparticles. Next, we present the microfabrication processes used to produce liquid cells with silicon nitride or silicon windows and then describe the loading and imaging procedures of the liquid-cell TEM technique. Several notes are included to provide helpful tips for the entire process, including how to manage the fragile cell windows. The individual motions of nanoparticles tracked by liquid-cell TEM revealed that changes in the solvent boundaries caused by evaporation affected the self-assembly process of nanoparticles. The solvent boundaries drove nanoparticles to primarily form amorphous aggregates, followed by flattening of the aggregates to produce a 2-dimensional (2D) self-assembled structure. These behaviors are also observed for different nanoparticle types and different liquid-cell compositions.

The liquid-cell is composed of a top chip and a bottom chip, which are equipped with silicon nitride windows that are transparent to an electron beam with a thickness of 25 nm. The top chip has a reservoir for storing the sample solution and evaporated solvent. The chips are made via conventional microfabrication processing25. The masks used for the top and bottom chips are shown in Figure 1a and 1b, r...

Watch this Scientific Journal Video about Liquid-cell Transmission Electron Microscopy for Tracking Self-assembly of Nanoparticles at JoVE.com

Liquid-cell Transmission Electron Microscopy for Tracking Self-assembly of Nanoparticles

Here we introduce experimental protocols for the real-time observation of a self-assembly process using liquid-cell transmission electron microscopy.

Drying a nanoparticle dispersion is a versatile way to create self-assembled structures of nanoparticles, but the mechanism of this process is not fully ...

Research

JoVE Journal

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 ...

Formation of Ordered Biomolecular Structures by the Self-assembly of Short Peptides

In nature, complex functional structures are formed by the self-assembly of biomolecules under mild conditions. Understanding the forces that control ...

Self-assembly of Complex Two-dimensional Shapes from Single-stranded DNA Tiles

Current methods in DNA nano-architecture have successfully engineered a variety of 2D and 3D structures using principles of self-assembly. In this ...

Obtaining 3D Chemical Maps by Energy Filtered Transmission Electron Microscopy Tomography

Energy filtered transmission electron microscopy tomography (EFTEM tomography) can provide three-dimensional (3D) chemical maps of materials at a ...

Analysis of Minerals Produced by hFOB 1.19 and Saos-2 Cells Using Transmission Electron Microscopy with Energy Dispersive X-ray Microanalysis

This video presents the use of transmission electron microscopy with energy dispersive X-ray microanalysis (TEM-EDX) to compare the state of minerals in ...

Using Graphene Liquid Cell Transmission Electron Microscopy to Study in Situ Nanocrystal Etching

Using Graphene Liquid Cell Transmission Electron Microscopy to Study in Situ Nanocrystal Etching

Graphene liquid cell electron microscopy provides the ability to observe nanoscale chemical transformations and dynamics as the reactions are occurring in ...

Performing Spectroscopy on Plasmonic Nanoparticles with Transmission-Based Nomarski-Type Differential Interference Contrast Microscopy

Differential interference contrast (DIC) microscopy is a powerful imaging tool that is most commonly employed for imaging microscale objects using ...

Preparation of Graphene-Supported Microwell Liquid Cells for In Situ Transmission Electron Microscopy

Preparation of Graphene-Supported Microwell Liquid Cells for In Situ Transmission Electron Microscopy

The fabrication and preparation of graphene-supported microwell liquid cells (GSMLCs) for in situ electron microscopy is presented in a stepwise protocol. ...

Synthesis of Monodisperse Cylindrical Nanoparticles via Crystallization-driven Self-assembly of Biodegradable Block Copolymers

The production of monodisperse cylindrical micelles is a significant challenge in polymer chemistry. Most cylindrical constructs formed from diblock ...

Self-Assembly of Hybrid Lipid Membranes Doped with Hydrophobic Organic Molecules at the Water/Air Interface

Because of their unique properties, including an ultrathin thickness (3-4 nm), ultrahigh resistivity, fluidity and self-assembly ability, lipid bilayers ...