Multi-Technique Approach for the Study of Block Copolymer-Mediated Gold Nanoparticles

A number of different techniques (UV-visible spectroscopy, small-angle neutron scattering, small-angle X-ray scattering, dynamic light scattering and transmission electron microscopy) have been used to characterize the synthesis of block copolymer-mediated gold nanoparticles in aqueous system. The measurements are carried out on high-yield gold nanoparticles as synthesized from HAuCl4 center dot 3H(2)O precursor in the presence of block copolymer along with trisodium citrate. UV-visible spectroscopy confirms the formation of gold nanoparticles by the presence of surface plasmon resonance (SPA) peak. The high contrast of gold nanoparticles for electrons and X-rays enables transmission electron microscopy (TEM) and small-angle X-ray scattering (SAXS) to determine the size distribution of gold nanoparticles. On the other hand, the high scattering contrast of neutrons for hydrogenous system in deuterated solvent allows small-angle neutron scattering (SANS) to examine the role of block copolymers in the synthesis. Dynamic light scattering (DLS) sees both the gold nanoparticles and block copolymer structures coexist during the synthesis.