Computational and Experimental Investigation of Janus-like Monolayers on Ultrasmall Noble Metal Nanoparticles
| Autor: | Mark Kester, David Green, Elise Hoover, Steven N. Merz, Zachary J. Farrell, Sergei A. Egorov, Joseph Pearring, Kateri H. DuBay |
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| Rok vydání: | 2018 |
| Předmět: |
Materials science
Monte Carlo method General Engineering General Physics and Astronomy Nanoparticle 02 engineering and technology engineering.material 010402 general chemistry 021001 nanoscience & nanotechnology Nanoscale morphology 01 natural sciences 0104 chemical sciences Chemical physics Monolayer engineering General Materials Science Noble metal Janus Self-assembly 0210 nano-technology Metal nanoparticles |
| Zdroj: | ACS Nano. 12:11031-11040 |
| ISSN: | 1936-086X 1936-0851 |
| DOI: | 10.1021/acsnano.8b05188 |
| Popis: | 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. |
| Databáze: | OpenAIRE |
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