Fast but Inaccurate or Slow but Accurate: The Dilemma of Tubes and Slip Links*

The tube model for entangled polymers projects a complex multi-body problem of interacting chains onto a mean-field representation. This popular framework has been enormously successful at predicting the rheology of model (and even some industrial) polymers. However, its success cloaks several fundamental problems that become obvious when it is subjected to strong tests. One such example is binary blends with well-separated relaxation times. In such cases, slip link models which retain the multi-body character of the original problem offer a more accurate and robust alternative. However, slip link models are computationally demanding. Here, I resuscitate a super-fast slip link model that Ron Larson and I first introduced over 15 years ago. With a few small modifications, it predicts the linear rheology of binary blends with remarkable accuracy and speed.