Bottlebrush polymers in the melt and polyelectrolytes in solution share common structural features
Joel M. Sarapas, Tyler B. Martin, Alexandros Chremos, Jack F. Douglas, Kathryn L. Beers
Abstract
Significance Bottlebrush polymer materials show great transdisciplinary promise, from tissue engineering to photonics. Homopolymers exhibit exceptionally low moduli while block brushes segregate into micrometer-sized domains. Both effects are attributed to the unique packing of brush polymers, a phenomenon that is difficult to measure without careful experimental design. Through precision synthesis and deuterium labeling, we studied a library of brush polymers in the melt using neutron scattering to quantitatively assess backbone packing. We show that bottlebrush polymers pack similarly to semidilute polyelectrolyte solutions, and that decreasing grafting density is analogous to increasing salt concentration in polyelectrolytes. These findings suggest hidden similarity in these different materials, one driven through sterics and the other through electrostatic repulsion.