Abstract: Effect of the amount of solubilized toluene on the hydrodynamic radius R_h of micelle of polyoxythylene(PEO)-polyoxypropylene(PPO) block copolymer was inves-tigated by dynamic lightscattering at different temperatures.
The result showed that the values of R_h were rather high due to strong hydration of PEO chains at 25 ℃, the amount of toluene in micelle had little effect on the values of R_h. As the temperature increased, hydration of micelle decreased and R_h decreased also. Near the temperature of the cloud point, the dehydration of micelle might be very strong, PPO core was swollen by toluent and aggregation number increased at higher temperatures, this made R_h increasing linearly with the amount of solubliized toluene.

Key words: Micelle of block copolymer, Solubilized toluene, Hydrodynamic radius