Capillarity-Driven Pinching Dynamics and Extensional Rheology of Dilute and Entangled Polymer Solutions

Concentration-dependent variation of macromolecular conformations and dynamics in polymer solutions are influenced by molecular weight, degree of overlap, solvent quality, and number density of entanglements. In this contribution, we characterize the shear and extensional rheology response of flexible polymer solutions using the broadest range of concentrations, spanning from ultra-dilute to highly entangled in solvent mixtures. We characterize the response to extensional flows realized in capillarity-driven pinching of a liquid necks by using the dripping-onto-substrate (DoS) rheometry protocols. The concentration-dependent variation in shear vs extensional rheology response reveals distinct influence of polymer and solvent properties. Lastly, we find standard predictions of FENE-P or Oldroyd-B models are inadequate to describe the observed radius evolution datasets.