Direct visualization of branched polymer dynamics using single molecule studies

We study the dynamics of single branched polymers in dilute and non-dilute solutions using single-molecule fluorescence microscopy. In particular, we use a hybrid enzymatic-synthetic approach to synthesize DNA-based branched polymers such as comb polymers that contain a long backbone with multiple side branches grafted at various positions. Following synthesis, we directly study the dynamics of single branched polymers, particularly in non-dilute solutions in extensional flow, and compare them to the dynamics of linear polymers. We further study the effects of background concentration and polymer topology on branched polymer dynamics in order to elucidate the non-equilibrium behavior of topologically complex polymers. For instance, our work on comb polymer dynamics has shown that contrary to dilute solutions and melts, the addition of branches on to a linear backbone speeds up the relaxation of comb polymers compared to their linear analogs in semi-dilute solutions. Overall, our work shows that single polymer dynamics can be used to provide a direct link between polymer microstructure and bulk rheological properties.