(189aj) Modeling Side Chain Conformations of Bottlebrush Polymers from iSAFT Density Functional Theory

A new density functional theory (DFT) formalism is designed to study the phase behavior of bottlebrush polymers in inhomogeneous systems. Bottlebrush polymers are macromolecules with polymeric side chains. They are of great research interest because of their potential applications such as rheology modifiers, polymeric photonics and drug-delivery vehicles. However, the structural details of bottlebrush polymers in solution are poorly understood. Particularly, conformational properties of the polymeric side-chains, including their flexibility and degree to which they are stretched, have not been elucidated. To provide new insight, we have developed a new DFT that is based on inhomogeneous statistical associating fluid theory (iSAFT). Assuming an infinitely long and rigid backbone, the theory is capable of predicting density distribution for the side chain segments. The effect of implicit solvent on bottlebrush polymers predicted by the theory agrees qualitatively with simulation results. Further the theory allows us to study how the side chain conformation varies with explicit solvent, different chain length, composition and grafting density. This theory has the advantages of lower computational expense compared with simulation and more detailed structural information compared with other theories, thus leading to a powerful tool to model bottlebrush polymer systems.