title: Yieldlike constitutive transition in shear flow of entangled polymeric fluids.
abstract: We describe an unexpected constitutive transition in entangled polymer solutions. At and beyond a critical stress, the initial spatially homogeneous and well-entangled sample transforms from its entangled (coiled) state into a fully disentangled (stretched) state over a period during which the resulting shear rate increases in a spatially inhomogeneous fashion. In the mode of controlled shear rate, the sample exhibits a stress plateau over three decades. Flow birefringence and normal stress observations unravel additional features of these flow phenomena.
authors: Department of Polymer Science and Maurice Morton Institute of Polymer Science, University of Akron, Akron, OH 44325, USA.
authors: Prashant
authors: P
authors: Tapadia
authors: Shi-Qing
authors: SQ
authors: Wang