Issue 42, 2020

Free-energy landscape of polymer-crystal polymorphism


Polymorphism rationalizes how processing can control the final structure of a material. The rugged free-energy landscape and exceedingly slow kinetics in the solid state have so far hampered computational investigations. We report for the first time the free-energy landscape of a polymorphic crystalline polymer, syndiotactic polystyrene. Coarse-grained metadynamics simulations allow us to efficiently sample the landscape at large. The free-energy difference between the two main polymorphs, α and β, is further investigated by quantum-chemical calculations. The results of the two methods are in line with experimental observations: they predict β as the more stable polymorph under standard conditions. Critically, the free-energy landscape suggests how the α polymorph may lead to experimentally observed kinetic traps. The combination of multiscale modeling, enhanced sampling, and quantum-chemical calculations offers an appealing strategy to uncover complex free-energy landscapes with polymorphic behavior.

Graphical abstract: Free-energy landscape of polymer-crystal polymorphism

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Article information

Article type
23 Jul 2020
02 Sep 2020
First published
03 Sep 2020
This article is Open Access
Creative Commons BY license

Soft Matter, 2020,16, 9683-9692

Free-energy landscape of polymer-crystal polymorphism

C. Liu, J. G. Brandenburg, O. Valsson, K. Kremer and T. Bereau, Soft Matter, 2020, 16, 9683 DOI: 10.1039/D0SM01342K

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