(79b) Shear-Induced Structures In Dilute Polymer Solutions

Shear flow has the ability to induce the formation of structures in polymers when both attractive and repulsive interactions are present. These structures have been observed and are important for a range of systems including hydrophobic poylelectrolytes and associative block copolymers. A tumbling polymer in shear flow undergoes a cycle of compression and expansion which can lead to a set of coil-globule-coil transitions. These systems are particularly challenging to model because of the separation of time and length scales between the tumbling process and the scale of the attractive and repulsive interactions. We have developed a new coarse grained model of polymer solutions that show shear-induced structures and have performed Brownian Dynamics simulations. We will discuss how the effective solvent quality and balance of attractive and repulsive interactions alter the flow transitions. We have analyzed the importance of a balance of the rotational and elongational components of shear in forming these structures and the ability to form irreversible structures using flow.