Tuesday, 16 May 2017

Particle-Based or Field-Based Models for Polymer Systems?

Compared to the systems which are composed of simple atoms or molecules, the structures of polymer systems in equilibrium are richer. The main reason is that a polymer molecule is composed of many monomers with the same or different chemical property. 

computational mathematics research journal
Take AB di block co polymers as an example. Each molecule has a form AA• • •ABB• ••B where the monomer A and B have different chemical properties. The equilibrium structures for di block co polymer, e.g., lamellar, hexagonal cylinder, bicontinuous gyroidand bcc sphere, etc., have been found for different composition of monomer B through computation and experiments. This equilibrium structures (A-rich and B-rich phase domain) with a length scale of 10-100 nm, is the result of competition of two factors: the repulsion of two chemically distinct monomer A and B, and the conformal entropy penalty. Since monomers A and B are connected in each molecule, monomer A and B are only be separated microscopically. Thus it is called micro separation.

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