화학공학소재연구정보센터
Macromolecules, Vol.35, No.16, 6397-6403, 2002
Kinetics of coarsening and precipitation of dilute polymer solutions: Fluorescence study of PEO in toluene
Fluorescence was used to follow the late stage phase demixing of a very dilute toluene solution of a poly(ethylene oxide)(-)(PEO) chain labeled at one end with pyrene. The excimer to monomer fluorescence intensities ratio is proportional to the average volume of the aggregates. From the linear region of the fluorescence intensity ratio variation with time the apparent rate constants of coarsening were calculated. The apparent rates of coarsening increase with the temperature quench depth, owing to the decrease of the solvent quality to the polymer. At long times, large aggregates are formed and precipitate. From the variation of the light-scattering intensity the apparent rates of precipitation were calculated. A linear correlation was observed between the apparent rates of coarsening and precipitation.