(364a) Engineering Surfaces and Interfaces in Polymer Films with Bottlebrush Polymer Additives

I will discuss the design of bottlebrush polymer additives for thin polymer films. Bottlebrush polymers are architecturally similar to comb polymers, but with a higher density of side chains (1 per backbone monomer). The highly branched architecture leads to unusual physics in polymer blends, such as limited miscibility with long linear polymers and a very strong attraction to surfaces and interfaces. First, we examined bottlebrush copolymer additives for thin films of immiscible polymers. These ternary blends can form two or three phases depending on the bottlebrush architecture. In three-phase systems, the bottlebrushes rapidly accumulate at the polymer/polymer interface and encapsulate the minority domains. This encapsulation layer traps the microstructure and suppresses coarsening under high temperature annealing. Second, we designed surface-active bottlebrush additives for commodity thermoplastics. In these systems, a balance between bulk miscibility and bottlebrush surface attraction controls the segregation profiles through the film thickness. We identify conditions where bottlebrush additives spontaneously accumulate at the free surface and substrate, offering a simple route to generate brush-like coatings with unique interfacial properties.