Modeling Bottlebrushes with Fluorinated Sidechains: Focus on Clusters Formation, Migration, and Restructuring at Interfaces

Molecular bottlebrushes are becoming a material of choice for various applications, largely because their structural characteristics and properties can be tailored in a straightforward manner by regulating their architectural parameters along with the chemical composition. Our experimental studies show that conventional thermoplastics such as PMMA, Nylon 6, and PET can exhibit extremely high water and oil repellency provided that only a small volume fraction of bottlebrush additives with fluorinated polyfluoropolyether (PFPE) sidechains is added to polymer matrices during their fabrication (Wei, Liying, et al. ACS Appl. Mater. Interfaces 12.34 (2020): 38626-38637). We develop a coarse-grained model of this system using dissipative particle dynamics (DPD) approach. The bottlebrush architecture and affinities between different moieties are chosen based on our concurrent experimental studies. We focus on the migration of the bottlebrush clusters onto the interfaces. We characterize the spreading of the bottlebrush cluster at the interface by calculating the shape anisotropy of this cluster and evolution of a number of contacts between different moieties. Our findings are in good agreement with the corresponding experimental results.