Abstract
Traditional post-treatment of colloidal nanoparticles (NPs) usually involves repeated centrifugation-wash-sonication processes to separate NPs from the original synthetic environment; however, such separation processes have either high energy cost or low efficiency and tend to cause aggregation. Here we show a general and scalable colloid post-processing technique based on density gradient centrifugation through water/oil interfaces. Such a one-step technique can switch the solvent in a colloid at almost any concentration without aggregation, and meanwhile purify colloidal nanoparticles by separating them from by-products and environmental impurities. Droplet sedimentation was shown to be the mechanism of this one-step concentration/purification process, and mathematical modeling was established to quantify the accumulation and sedimentation velocities of different NPs.
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References
Yin, Y.; Alivisatos, A. P. Colloidal nanocrystal synthesis and the organic-inorganic interface. Nature 2005, 437, 664–670.
Burda, C.; Chen, X.; Narayanan, R.; El-Sayed, M. A. Chemistry and properties of nanocrystals of different shapes. Chem. Rev. 2005, 105, 1025–1102.
Xia, Y.; Xiong, Y.; Lim, B.; Skrabalak, S. E. Shape-Controlled synthesis of metal nanocrystals: Simple chemistry meets complex physics? Angew. Chem. Int. Ed. 2009, 48, 60–103.
Wang, D.; Xin, H. L.; Hovden, R.; Wang, H.; Yu, Y.; Muller, D. A.; DiSalvo, F. J.; Abruña, H. D. Structurally ordered intermetallic platinum-cobalt core-shell nanoparticles with enhanced activity and stability as oxygen reduction electrocatalysts. Nat. Mater. 2013, 12, 81–87.
Zhou, Z. Y.; Tian, N.; Li, J. T.; Broadwell, I.; Sun, S. G. Nanomaterials of high surface energy with exceptional properties in catalysis and energy storage. Chem. Soc. Rev. 2011, 40, 4167–4185.
Wang, D. S.; Li, Y. D. Bimetallic nanocrystals: Liquid-phase synthesis and catalytic applications. Adv. Mater. 2011, 23, 1044–1060.
Norris, D. J.; Efros, A. L.; Erwin, S. C. Doped nanocrystals. Science 2008, 319, 1776–1779.
Huynh, W. U.; Dittmer, J. J.; Alivisatos, A. P. Hybrid nanorod-polymer solar cells. Science 2002, 295, 2425–2427.
Liu, N.; Lu, Z.; Zhao, J.; McDowell, M. T.; Lee, H. W.; Zhao, W.; Cui, Y. A pomegranate-inspired nanoscale design for large-volume-change lithium battery anodes. Nat. Nanotechnol. 2014, 9, 187–192.
Zrazhevskiy, P.; Gao, X. H. Quantum dot imaging platform for single-cell molecular profiling. Nat. Commun. 2013, 4, 1619.
Xia, X.; Wang, Y.; Ruditskiy, A.; Xia, Y. 25th anniversary article: Galvanic replacement: A simple and versatile route to hollow nanostructures with tunable and well-controlled properties. Adv. Mater. 2013, 25, 6313–6333.
Doane, T. L.; Burda, C. The unique role of nanoparticles in nanomedicine: Imaging, drug delivery and therapy. Chem. Soc. Rev. 2012, 41, 2885–2911.
Ma, W.; Kuang, H.; Xu, L.; Ding, L.; Xu, C.; Wang, L.; Kotov, N. A. Attomolar DNA detection with chiral nanorod assemblies. Nat. Commun. 2013, 4, 2689.
Strmcnik, D.; Uchimura, M.; Wang, C.; Subbaraman, R.; Danilovic, N.; van der Vliet, D.; Paulikas, A. P.; Stamenkovic, V. R.; Markovic, N. M. Improving the hydrogen oxidation reaction rate by promotion of hydroxyl adsorption. Nat. Chem. 2013, 5, 300–306.
Wang, Y.; Chen, G.; Yang, M.; Silber, G.; Xing, S.; Tan, L. H.; Wang, F.; Feng, Y.; Liu, X.; Li, S. et al. A systems approach towards the stoichiometry-controlled hetero-assembly of nanoparticles. Nat. Commun. 2010, 1, 87.
Wang, X.; Li, G.; Chen, T.; Yang, M.; Zhang, Z.; Wu, T.; Chen, H. Polymer-encapsulated gold-nanoparticle dimers: Facile preparation and catalytical application in guided growth of dimeric ZnO-nanowires. Nano Lett. 2008, 8, 2643–2647.
Skrdla, P. J. Roles of nucleation, denucleation, coarsening, and aggregation kinetics in nanoparticle preparations and neurological disease. Langmuir 2012, 28, 4842–4857.
Arnold, M. S.; Green, A. A.; Hulvat, J. F.; Stupp, S. I.; Hersam, M. C. Sorting carbon nanotubes by electronic structure using density differentiation. Nat. Nanotechnol. 2006, 1, 60–65.
Mastronardi, M. L.; Henderson, E. J.; Puzzo, D. P.; Ozin, G. A. Small silicon, big opportunities: The development and future of colloidally-stable monodisperse silicon nanocrystals. Adv. Mater. 2012, 24, 5890–5898.
Bai, L.; Ma, X.; Liu, J.; Sun, X.; Zhao, D.; Evans, D. G. Rapid separation and purification of nanoparticles in organic density gradients. J. Am. Chem. Soc. 2010, 132, 2333–2337.
Li, S.; Chang, Z.; Liu, J.; Bai, L.; Luo, L.; Sun, X. Separation of gold nanorods using density gradient ultracentrifugation. Nano Res. 2011, 4, 723–728.
Sun, X.; Tabakman, S. M.; Seo, W. S.; Zhang, L.; Zhang, G.; Sherlock, S.; Bai, L.; Dai, H. Separation of nanoparticles in a density gradient: FeCo@C and gold nanocrystals. Angew. Chem. Int. Ed. 2009, 48, 939–942.
Chen, G.; Wang, Y.; Tan, L. H.; Yang, M.; Tan, L. S.; Chen, Y.; Chen, H. High-purity separation of gold nanoparticle dimers and trimers. J. Am. Chem. Soc. 2009, 131, 4218–4219.
Xu, J.; Wang, H.; Liu, C.; Yang, Y.; Chen, T.; Wang, Y.; Wang, F.; Liu, X.; Xing, B.; Chen, H. Mechanical nanosprings: Induced coiling and uncoiling of ultrathin Au nanowires. J. Am. Chem. Soc. 2010, 132, 11920–11922.
Brakke, M. K.; Daly, J. M. Density-gradient centrifugation: Non-ideal sedimentation and the interaction of major and minor components. Science 1965, 148, 387–389.
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Kuang, Y., Song, S., Liu, X. et al. Solvent switching and purification of colloidal nanoparticles through water/oil Interfaces within a density gradient. Nano Res. 7, 1670–1679 (2014). https://doi.org/10.1007/s12274-014-0527-7
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DOI: https://doi.org/10.1007/s12274-014-0527-7