Mesoscale Modelling of Block Copolymers under External Fields.

Abstract

A remarkable feature of block copolymer systems is their ability to self-assemble into a variety of ordered structures with domain sizes in the mesoscale range. One of the open questions is the dynamics of structure formation, which can be highly dependent on external fields often present in industrial conditions, such as shear, temperature gradients and confinement, or external fields which are employed to manipulate the structure, such as electric and magnetic fields. An understanding of the external field effects and effects of architecture and composition of block copolymer systems is crucial, since these factors may have a large impact on the structure formation and consequently on the structural and physical properties of the final product. In the present thesis I have focused on the comparison of results of the existing Dynamic Self Consistent Field Theory (DSCFT) with experimental observations for specific experimental systems as well as on the prediction of generic dynamic phenomena for chosen model systems. A detailed comparison with experiments was possible due to the development of such state-of-the-art experimental techniques as dynamic Scanning Force Microscopy. We have shown that the static behavior as well as the dynamics of phase transitions under an external field is well described by the theory for a number of experimental systems. This thesis demonstrates that this symbiotic approach is valuable; the experiments validate the theoretical calculations and the calculations rationalize the experimental observations. Eventually, the method can be employed to make predictions and propose improvements for yet less understood experimental and industrial systems.