Abstract
Hypothesis: Aqueous citrate-stabilized gold nanoparticles (Au NPs) cannot be directly transferred from water to an immiscible organic solution using short alkyl ligands. However, Au NPs can be transferred from water to a water-organic interface if chemical and mechanical inputs are used to modify the interfacial energy and interfacial area. Ligand exchange can then take place at this interface. After separating the particles from the liquids, they can be transferred to a different organic phase. Experiments: Hexane, alkylamine, and acetone were added to aqueous citrate-stabilized Au NPs to form a film at the system interfaces. After removing the liquid phases, Au NPs were readily redispersed into tetrahydrofuran (THF). The size and shape of the transferred Au NPs were evaluated by transmission electron microscopy (TEM) and small angle X-ray scattering (SAXS). Findings: Au NPs with 13 nm diameter are readily segregated from water with the aid of short alkylamine ligands. They form a thin film at the water/organic solvent interface, rendering them easy to separate from the liquid phases and possible to redisperse into another organic solvent. After the phase transfer process, Au NPs were functionalized with short amine ligands. In addition, the shape and size of Au NPs were preserved. The short amine-protected Au NPs in THF can stay stable for up to 27 days or longer.
| Original language | English |
|---|---|
| Pages (from-to) | 164-172 |
| Number of pages | 9 |
| Journal | Journal of Colloid and Interface Science |
| Volume | 460 |
| DOIs | |
| State | Published - Dec 15 2015 |
| Externally published | Yes |
Funding
This work was supported by the Florida State University , the FAMU-FSU College of Engineering, and the Chemical and Biomedical Engineering Department. The authors also wish to acknowledge the FAMU-FSU College of Engineering machine shop and the Aero-propulsion, Mechatronics, and Energy Center for other technical support. SAXS experiments are supported by the High-Performance Materials Institute (HPMI) at Florida State University. We thank Dr. Richard Liang, Dr. Ted Liu, and Dr. Gregory Stone for helpful discussions. TEM was performed at the National High Magnetic Field Laboratory, which is supported by National Science Foundation Cooperative Agreement No. DMR-1157490 and No. DMR-0654118 and the State of Florida. We acknowledge Dr. Yifeng Su and Dr. Yan Xin for TEM technical support. Assistance with the UV–vis experiments was provided by Dr. Gang Chen. Assistance with the FTIR-ATR experiments was provided by Onyekachi Oparaji. Assistance with the SAXS data processing was provided by Leon Gonzalez.
| Funders | Funder number |
|---|---|
| Chemical and Biomedical Engineering Department | |
| FAMU-FSU College of Engineering | |
| High-Performance Materials Institute | |
| National Science Foundation | DMR-1157490 |
| Florida State University |
Keywords
- Dodecylamine
- Gold nanoparticle (Au NP)
- Hard sphere model
- Hexylamine
- Nonylamine
- Phase transfer
- Short alkyl ligand
- Small angle X-ray scattering (SAXS)