Authors
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Merz, S.N. ; Farrell, Z. ; Pearring, J. ; Hoover, E. ; Kester, M. ; Egorov, S. A. ; Green, D.L. ; DuBay, K.H.
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Title
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Computational and experimental investigation of Janus-like monolayers on ultrasmall noble metal nanoparticles
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Date
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22.10.2018
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Number
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55943
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Abstract
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Detection of monolayer morphology on nanoparticles smaller than 10 nm has proven difficult with traditional visualization techniques. Here matrix-assisted laser desorption ionization mass spectrometry (MALDI-MS) is used in conjunction with atomistic simulations to detect the formation of Janus-like monolayers on noble metal nanoparticles. Silver metal nanoparticles were synthesized with a monolayer consisting of dodecanethiol (DDT) and mercaptoethanol (ME) at varying ratios. The nanoparticles were then analyzed using MALDI-MS, which gives information on the local ordering of ligands on the surface. The MALDI-MS analysis showed large deviations from random ordering, suggesting phase separation of the DDT/ME monolayers. Atomistic Monte Carlo (MC) calculations were then used to simulate the nanoscale morphology of the DDT/ME monolayers. In order to quantitatively compare the computational and experimental results, we developed a method for determining an expected MALDI-MS spectrum from the atomistic simulation. Experiments and simulations show quantitative agreement, and both indicate that the DDT/ME ligands undergo phase separation, resulting in Janus-like nanoparticle monolayers with large, patchy domains.
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Publisher
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ACS Nano
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Wikidata
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Q57800387
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Citation
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ACS Nano 12 (2018) 11031-11040
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DOI
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https://doi.org/10.1021/acsnano.8b05188
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Tags
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atomistic simulations maldi-tof monte carlo nanoparticles self-assembly
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