(57f) Computational Studies of Polymer Morphology Evolution in Drying Films

Film drying processes are important to achieving polymer films and membranes with micro and nano-structures tailored for applications ranging from advanced lithography to nanofiltration. We discuss a model and computational approach that enables the investigation of polymer morphology development by diffusion during the unidirectional drying of a polymer solution. The model is built on thermodynamic forces constructed from self-consistent field theory and can address the kinetics of phase transformations associated with the drying and ordering of complex polymer components such as block copolymers. As a first application of the model, we examine the drying of a solution of an asymmetric diblock copolymer, where the diblock assumes a hexagonal cylindrical mesophase in the dry state. We discuss the solution and solvent evaporation conditions for which cylinders formed at the drying front are oriented parallel or perpendicular to the substrate of the film and propagate in the same orientation through the film as the drying process continues. A particular focus is on identifying conditions where the technologically significant perpendicular orientation can be consistently achieved.