S-Space College of Engineering/Engineering Practice School (공과대학/대학원) Dept. of Chemical and Biological Engineering (화학생물공학부) Journal Papers (저널논문_화학생물공학부)
Gelation Behavior of PEO-PLGA-PEO Triblock Copolymers in Water
- Kwon, Kwan-Wook; Park, Moon Jeong; Bae, You Han; Kim, Hong Doo; Char, Kookheon
- Issue Date
- Polymer 2002;43:3353
- Poly(ethylene oxide)–poly(lactic acid-co-glycolic acid)–poly(ethylene oxide) (PEO–PLGA–PEO) triblock copolymer(s); Turbidity; Storage modulus (G′)
- Aqueous solutions of poly(ethylene oxide-b-( -lactic acid-co-glycolic acid)-b-ethylene oxide) with two different molecular weights (550–3.4K–550 and 750–3.5K–750) show the change in turbidity as a function of temperature. The variation in turbidity is also found to be independent of block copolymer concentration. By increasing the molecular weight of the hydrophilic PEO end block with the molecular weight of the hydrophobic PLGA middle block kept almost the same, it is found that the phase boundary is shifted to a higher temperature and only soft gels are observed. Large aggregates or clusters of micelles with sizes larger than 5000 nm are observed with dynamic light scattering at the temperatures of turbid region and the size distribution of the aggregates is also found to depend only on temperature, not on concentration. The storage moduli (G′) of aqueous solutions of the PEO–PLGA–PEO do not show the abrupt change at the sol-to-(hard) gel boundary, as normally seen in the case of PEO–PPO (poly(propylene oxide))–PEO block copolymers and the behavior of G′ as a function of temperature is qualitatively the same and independent of polymer concentration except the absolute values of G′, which are proportional to the copolymer concentration. This implies that micelle–micelle clusters are formed due to hydrophobic attraction between core phases.
- Files in This Item: There are no files associated with this item.