Dynamics of small molecules within the F127 PEO-PPO-PEO triblock copolymer gel and sol phases studied at the molecular scale.

Triplet excited states of guest molecules with different hydrophobicities were used to probe the association and dissociation dynamics of these guests with F127 micelles in the gel and sol phases. The dynamics probed was on a longer length scale than amenable with fluorescence techniques, but at a shorter length scale than probed in translational diffusion studies. The mobility of the guests at the molecular scale showed that subtle changes in the guest's structure affect the guest's release time from the micelles, where the structural features of the guest are more important than the phase, gel vs. sol, of the system.