(602e) Structure-Property Relationships Via Recovery Rheology in Polymeric Materials

Lee, J. C. W., University of Illinois at Urbana-Champaign
Weigandt, K., National Institute of Standards and Technology
Rogers, S., University of Illinois, Urbana-Champaign
The recoverable strain is shown to correlate to the temporal evolution of microstructure via time-resolved small-angle neutron scattering (SANS) and dynamic shear rheology. Investigating two distinct polymeric materials of wormlike micelles and fibrin, we demonstrate that, in addition to the nonlinear rheological structure-property relationships from SANS, the shear and normal stress evolution is dictated by the recoverable strain. A distinct sequence of physical processes under large amplitude oscillatory shear (LAOS) is identified that clearly contains information regarding both the steady-state flow curve and the linear-regime frequency sweep, contrary to most interpretations that LAOS responses are either distinct from, or somehow intermediate between the two cases. This work provides a physically-motivated and straightforward path to further explore the structure-property relationships of polymeric materials under dynamic flow conditions.