S-Space College of Engineering/Engineering Practice School (공과대학/대학원) Dept. of Chemical and Biological Engineering (화학생물공학부) Journal Papers (저널논문_화학생물공학부)
Hydrophobic attraction of pyrene-end-labeled poly(ethylene glycol) in water and water-methanol mixtures
- Char, Kookheon; Frank, Curtis W.; Gast, Alice P.; Tang, Wing T.
- Issue Date
- American Chemical Society
- Macromolecules, 1987, 20, 1833
- Fluorescence stationary-state measurements of pyrene-end-labeled poly(ethy1ene glycols) (Py-PEG-Py) of three different molecular weights are presented. In aqueous solution the excimer to monomer intensity ratio, Ie/Im, in the intramolecular excimer region decreases as the polymer molecular weight is increased. For Py-PEG-Py of PEG weight-average molecular weight of 4800, the Ie/Im does not scale according to the Wilemski-Fixman theory based on a diffusion-controlled end-to-end cyclization process. Surprisingly, this Py-PEG-Py(4800) phase separates. We believe that these observations are due to a hydrophobic attraction between pyrene groups. The addition of methanol reduces the hydrophobic attraction by the preferential solvation of methanol molecules around the pyrene group.
- 0024-9297 (print)
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