Can polymer properties be predicted from theory?

Dr. Eva von Domaros, Friedrich Schiller University Jena, Germany

The material class of polymers is not only extremely large and complex. Polymers are important parts of our daily lives as plastics or biopolymers like sugars or the DNA backbone. The theoretical understanding—let alone the prediction—of polymer properties is very demanding. The reason therefore is a combination of polymer characteristics. Very large system sizes that easily reach thousands of repeating subunits are hardly feasible for accurate electronic structure methods such as DFT. Furthermore, in contrast to crystalline compounds, polymers are amorphous and lack periodic symmetry, which can be exploited for crystals in periodic calculations. Theoretical models which are capable of treating these systems necessarily apply approximations such as parameterized force fields and, hence, are less accurate and reliable.

In this presentation, a novel approach to understand and later on predict macroscopic properties of this diverse material class is presented. The so-called Quantum Cluster Equilibrium (QCE) method is based on a statistical approach which allows to transfer highly reliable electronic structure data to macroscopic phases. The QCE method will be introduced and demonstrated at the example of liquid systems. Afterwards, the extension to amorphous systems such as polymers will be demonstrated, and promising applications will be presented. Finally, it will be shown which properties are within the reach of this method and the limitations will be discussed.