Chaotic boundaries of nematic polymers in mixed shear and extensional flows.

Chaotic orientational dynamics of sheared nematic polymers is documented in laboratory experiments and predicted by Doi-Hess kinetic theory for infinitely thin rods. We address robustness of rheochaos when simple shear is modified by a planar straining flow, and the macromolecules have finite aspect ratio. We predict persistence of sheared chaotic response up to a threshold straining flow strength and minimum aspect ratio, beyond which chaotic behavior is arrested. More intriguing, a straining component can induce chaos from periodic shear responses.