Structure and Morphology of Gold Nanoparticles in Solution Studied by TEM, SAXS and UV-Vis

Gold nanoparticles have a great number of applications, among others in material sciences, biology and medicine. A method for the synthesis of gold nanoparticles in solution with the use of gemini surfactant was proposed and the nanoparticles obtained were subjected to thorough characterisation. The method proposed is a modification of the Turkevich method, based on reduction of tetrachloroauric acid in the presence of trisodium citrate and a dicationic (gemini) surfactant - 1,1'-(1,4-butan)bis(3-dodecyloxymethylimidazolium) di-propionate. Morphology and size distribution of gold nanoparticles obtained were examined by the transmission electron microscopy (TEM), UV-Vis spectroscopy and small angle scattering of synchrotron radiation (SAXS). The plasmon resonance of the nanoparticles obtained was observed in the wavelength range corresponding to the presence of gold nanoparticles with sizes ranging from 5 to 100 nm. TEM images confirmed that the spherical shape of nanoparticles was dominated in reference solutions prepared of sodium citrate and tetrachloroauric acid. In the solutions prepared with addition of gemini surfactant, the gold nanoparticles of triangular morphology were observed.