Core-Corona Micelles from Bottlebrush and Star-like Polymers at Liquid-Liquid Interfaces*

It has been found that amphiphilic bottlebrushes and star polymers are very effective stabilizers of oil/water interfaces. A main feature of these polymers is their highly customizable architectural parameters, such as backbone and sidechain lengths, as well as their chemical compatibility with solvents, impacting their behavior at oil/water interfaces. Thus, it would be possible to tailor emulsion efficiency by controlling these molecular parameters and understanding their relation to surface activity. In this work, molecular simulations have been used to provide structure-interfacial property relationships for bottlebrush and star-like polymers composed by hydrophilic sidechains as well as sidechains that combine hydrophobic and lipophobic properties. Simulations were carried out at planar and spherical oil/water interfaces with varying polymer surface concentration. To characterize polymer structure, morphological quantities such as radius of gyration, relative shape anisotropy parameter, and end-to-end distances of grafted chains and backbone were computed. Interfacial tension and surface pressure as functions of polymer architecture and concentration at planar interfaces were also computed. Interestingly, our simulations predict the formation of highly ordered nanopatterned interfaces decorated by core-corona micelles formed by bottlebrush and star-like polymers. Transitions between different nanopatterns can be induced by changing polymer surface concentration.