E. Continuous shear
Whether the observed inhomogeneous shear seen in startup shear described above in A would persist at high strains is a question of essential importance. Inhomogeneous shear develops because well-entangled polymers respond like a solid when subjected to a shear rate much higher than its terminal relaxation rate. In this nonlinear flow regime, entangled polymers are like jelly when sheared. Once broken as revealed in Movie 2”, the system apparently continues to take advantage of this localized failure, allowing the rest to avoid breakup.
shows continuous shear at a rate of 2.5 s-1 that lasted for two and half minutes before shear cessation.