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Phase Transfer of Nanoparticles Using an Amphiphilic Ionic Liquid

Qu, Mei, Chen, Shuai, Ma, Wenbao, Chen, Jiangang, Kong, Kang, Zhang, Fengwei, Li, Huan, Hou, Zhenshan, Zhang, Xian-Ming
Langmuir 2016 v.32 no.51 pp. 13746-13751
Fourier transform infrared spectroscopy, ambient temperature, benzoic acid, butanol, gold, hydrogen bonding, hydrophobicity, ionic liquids, ligands, nanoparticles, palladium, potassium bromide, silica, silver, sodium chloride, surfactants, toluene
The phase transfer of nanoparticles (NPs) from water to organic solvents by an amphiphilic room-temperature ionic liquid (IL) was reported. The geminal IL modified with Pluronic P123 stabilizes a variety of NPs of different size and nature, such as Pd, Au, Ag, and SiO₂ NPs. Their phase transfer into a hydrophobic environment was realized by raising the temperature and adding salts (such as NaCl and KBr), both of which have a common effect of breaking the hydrogen bonds of the IL with H₂O. A more straightforward method of using an organic solvent working as a hydrogen bond donor (such as butyl alcohol) was then proposed. In this case, NaCl was no longer required. To further apply this strategy to the organic solvents that are generally incapable of forming hydrogen bonds (e.g., toluene), a small quantity of benzoic acid was added to the organic phase. By forming hydrogen bonds from benzoic acid to the IL, an even more facile approach was provided. FT-IR confirmed the hydrogen bonding between them. The phase-transfer protocol does not rely on coordination bonding of ligands with a specific metal and is capable of the phase transfer of objects with large sizes and different natures. Thus, it has the potential for wide application.