Designing Bottlebrush Additives with Polyfluoropolyether (PFPE) Sidechains: Focus on Bottlebrush Architecture and Effects of Solvent Quality

Molecular bottlebrushes are rapidly becoming a material of choice for a plethora of applications, ranging from electronic and photonic materials to thermal stabilization of enzymes. Our experimental studies show that addition of only a minute fraction of bottlebrushes with polyfluoropolyether (PFPE) sidechains results in a dramatic improvement of oleophobicity of polymer matrix. PFPE has a low surface energy and is of interest because it is non-toxic and environmentally friendly due to its chemical inertness. We develop a coarse-grained model of this amphiphilic bottlebrush using dissipative particle dynamics (DPD) approach and validate our model with respect to the prior molecular dynamics simulations and experimental studies. We focus on dynamics of phase separation and self-assembly of clusters of bottlebrushes in the solvents of various quality and in various polymer matrices. We characterize domain growth dynamics and evolution of cluster aggregation in the polymer matrix/bottlebrush/solvent system. We show that clusters sizes, morphologies, and shape anisotropies are controlled by the bottlebrush architecture and affinities between all the moieties within the system.