title: A convenient phase transfer protocol to functionalize gold nanoparticles with short alkylamine ligands.
abstract: OBJECTIVE
  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.
  
  
  METHODS
  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).
  
  
  RESULTS
  Au NPs with 13nm 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 27days or longer.
authors: Florida State University, Aero-Propulsion, Mechatronics & Energy Center, 2003 Levy Avenue, Tallahassee, FL 32310, USA; Florida A&M University - Florida State University College of Engineering, Department of Chemical and Biomedical Engineering, 2525 Potsdammer Street, Tallahassee, FL 32310, USA. Electronic address: gy12b@my.fsu.edu.
authors: Guang
authors: G
authors: Yang
authors: Green Energy & Environment Laboratories/ITRI, Rm. 307B, Bldg. 64, 195, Sec. 4, Chung Hsing Rd., Chutung, Hsinchu 31040, Taiwan, ROC. Electronic address: chang0719@itri.org.tw.
authors: Wen-Sheng
authors: WS
authors: Chang
authors: Florida State University, Aero-Propulsion, Mechatronics & Energy Center, 2003 Levy Avenue, Tallahassee, FL 32310, USA; Florida A&M University - Florida State University College of Engineering, Department of Chemical and Biomedical Engineering, 2525 Potsdammer Street, Tallahassee, FL 32310, USA. Electronic address: dhallinan@fsu.edu.
authors: Daniel T
authors: DT
authors: Hallinan
keywords: Dodecylamine; Gold nanoparticle (Au NP); Hard sphere model; Hexylamine; Nonylamine; Phase transfer; Short alkyl ligand; Small angle X-ray scattering (SAXS)