Diffusion of Gold Nanorods in Polymer Solutions

We studied translational and rotational diffusion of gold nanorods (AuNRs) in poly(ethylene glycol) (PEG)- water solutions using polarized fluorescence correlation spectroscopy. AuNRs of aspect ratio 3.8 and two different molecular weights (5 kg/mol and 35 kg/mol) of PEG were used. Rotational diffusion constant (Dr) and translational diffusion constant (Dt) for AuNRs were in agreement with the theoretical calculations using Stick theory, Tirado and Garcia de la Torre's, and Broersma's relations. For higher molecular weight PEG-water solution at high concentrations, we observed faster rotational diffusion compare to theoretical estimates.