Effect of alkyl chain length on phase transfer of surfactant capped Au nanoparticles across the water/toluene interface

What can be inferred from bacterium–nanoparticle interactions about the potential consequences of environmental exposure to nanoparticles?

“…Oligochitosan stabilised 8 nm Ag-np have a pH-dependant f-potential which ranges from 28 mV at pH 2.4 to -56 mV at pH 11 (Long et al 2007). Freshly prepared Au-np have a f-potential of -30 mV at an undisclosed pH (Zhu et al 2005), but once coated with thioglycolic acid/cetyltrimethyl ammonium bromide the particles possess a charge of 23 mV. Un-capped TiO 2 -np have an IEP of approximately pH 5.8 and thus at physiological pH of 7 possess a f-potential of -20 mV (Liufu et al 2005).…”

A convenient phase transfer protocol to functionalize gold nanoparticles with short alkylamine ligands

“…Transfer from aqueous to organic media is normally done with the assistance of alkylthiols, alkyamines, or other similar ligands [29][30][31][32][33][34][35]. For example, octadecylamine (ODA) was used to transfer Au NPs produced in water to toluene by vigorously shaking the biphasic mixture [29].…”

Close‐Packed Gold‐Nanocrystal Assemblies Deposited with Complete Selectivity into Lithographic Trenches

“…The patterned wafer is attached to the negative electrode using a copper clamp, which ensures robust electrical connection between the highly doped silicon substrate and the gold electrode. The gold particles are observed to have a net positive charge, and are attracted to the negative electrode under the influence of an electric field of 200 V. The cationic character of surfactant-coated gold nanocrystals in toluene has been previously observed experimentally by Zhu et al [15] In our study, the particles migrate in the poorly conducting toluene medium towards the negative electrode, at which they undergo electrophoretic discharge. Figure 1d shows typical current-time curves, obtained from the anhydrous solution at 200 V with and without the presence of gold nanoparticles, labeled a and b, respectively.…”

“…The Zeta potential of gold nanocrystals (0.36 Â 10 À3 mol dm À3 ) in anhydrous toluene was experimentally determined as (2.4 AE 0.1) mV, confirming the presence of a net positive particle charge. [15] The completely selective deposition of the nanocrystals into the trenches fabricated using electron beam lithography is strongly mediated by the greater conductivity of the nanocrystal/toluene dispersion to the 30 nm SiO 2 trench walls (10 14 -10 16 V cm). This results in a nonuniform electric field between the highly doped trench base and the counter electrode, with the field lines deflecting towards the conductive channels.…”