Influence of Polymer Architecture on Extensional Solution Flow

Solution flows are a critical component in our understanding of spray applications and biological functions. Drop-on-substrate rheology (DOSR) offers strong insights into the fluid dynamics of non-Newtonian droplet breakup. Polymers, when combined in solution, play a stabilizing role during the droplet breakup process as a result of their elasticity. By modifying the architecture of a linear polymer backbone, these elastic contributions can be altered to significantly influence solution flow properties. We have studied the extensional flow behaviors of both graft and liquid-crystalline polymers with DOSR as each species exhibits unique architectures of varying degrees of backbone linearization and dissymmetries between monomer subunits. Namely, we have focused on grafting methoxy polyethylene glycol amine onto hydrolyzed polyacrylamide at various grafting densities. Changes in size scale were then confirmed via light scattering and viscometry. Finally, the relaxation times of graft polymer in solution were compared to liquid crystal flows to understand the full spectrum of the effect of backbone flexibility.