Abstract
The phase behavior of poly(styrene)--poly(1,4-butadiene) diblock copolymers with a polymer block invariant degree of polymerization shows no evidence of Frank-Kasper phases, in contrast to low molar mass diblock copolymers () with the same conformational asymmetry. A universal self-concentration crossover parameter is identified, directly related to the crossover to entanglement dynamics in polymer melts. Mean-field behavior is recovered when , while complex low symmetry phase formation is attributed to fluctuations and space-filling constraints, which dominate when .
- Received 14 May 2018
- Revised 6 September 2018
DOI:https://doi.org/10.1103/PhysRevLett.121.208002
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