Journal article
Effects of PEO-PPO diblock impurities on the cubic structure of aqueous PEO-PPO-PEO pluronics micelles: fcc and bcc ordered structures in F127
We report on structural properties of PEO-PPO-PEO type of triblock block copolymers (Pluronics F127) with special emphasis on the effect of diblock PEO-PPO impurities on the ordered gel phase. Commercial F127 polymers contain as received roughly 20% PEO-PPO diblock and 80% PEO-PPO-PEO triblock copolymers.
Aqueous solutions of F127 copolymers used as received form fee ordered micellar structure. Copolymers depleted with respect to the diblock impurity, resulting in a pure PEO-PPO-PEO triblock copolymer system, form bcc ordered micelles within the major parts of the gel phase. However, close to the disorder-to-order transition, the purified F 127 copolymer system also forms fcc structure, thus giving rise to a novel sequence of micellar phases: disorder-fcc-bcc.
This is the phase sequence predicted theoretically for pure block copolymer melts.
Language: | English |
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Year: | 2008 |
Pages: | 1720-1727 |
ISSN: | 15205835 and 00249297 |
Types: | Journal article |
DOI: | 10.1021/ma702269c |
ORCIDs: | 0000-0002-8998-9390 |