Despite the ubiquity of intentional or unintentional polydispersity in chain lengths of diblock copolymers, its effects on microphase separation in thin films have eluded a clear understanding. In this talk, we will present our ongoing efforts in understanding effects of polydispersity on morphology in thin films by combining field theory-based simulations and neutron reflectivity experiments. In particular, films containing either lamellar or cylinder forming diblock copolymers with one nearly monodisperse and the other highly polydisperse block will be discussed. Also, structure determination of nanostructured composites obtained by blending the diblock copolymers with spherical nanoparticles will be discussed. Polydispersity induced stabilization of coexisting lamellar and cylindrical morphologies in thin films containing cylinder forming diblock copolymers will be discussed. Origin of such a stabilization lies in the entropic segregation of short and long chains among lamellar and cylindrical domains. Furthermore, our approach to directly use simulations (self-consistent field theory or hybrid-particle field theory-based models) for the analysis of the experimental reflectometry data will be discussed. As an outlook, combining field theory-based simulations and neutron reflectivity experiments provides a pathway for quantitative predictions of the structural properties of polydisperse block copolymer nanocomposite thin films.

Effects of polydispersity on microphase separation in thin films of diblock copolymers: Theories, simulations, and experiments

2019 Spring National Meeting

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