Size distribution of gold nanoparticles covered with thiol-terminated cyanobiphenyl-type liquid crystal molecules studied with small-angle X-ray scattering and TEM

We have generated gold nanoparticles bound to the octyl group of 4'-octyloxy-4-cyanobiphenyl through thiolation of the terminal group. Two methods were employed for the generation. The first ligand exchange method produced the particles with a mono-dispersed size distribution, while the second method of photochemical reduction led to a bimodal particle size distribution. Small-angle X-ray scattering signals have shown that in the latter method the size of a seed particle formed in a precursor complex suspension remains almost unchanged, and hindered collisions among the particles can induce their heterogeneous coalescence in response to photoirradiation. (C) 2008 Elsevier B.V. All rights reserved.