Effect of Chain Length of PEO on the Gelation and
Micellization of the Pluronic F127 Copolymer Aqueous System
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Abstract
The
effect of adding homopolymer poly(ethylene oxide) (PEO) on the sol/gel
behavior of amphiphilic triblock copolymer Pluronic F127 ((EO)<sub>98</sub>(PO)<sub>67</sub>(EO)<sub>98</sub>) in aqueous media is explored.
Emphasis is placed on the influence of the PEO molecular weight and
concentration on micellization and gelation and the exploration of
their correlation. PEO is always found to lower the critical micellization
temperature modestly. However, short PEO chains promote the gelation
of F127, and long chains delay or even curb gel formation. Micelle
size measurements and cryo-TEM micrographs provide evidence for micellar
aggregation via the bridging of long PEO chains or depletion flocculation,
thereby impeding the ordering of micelles for gel formation
