Pasquino, Rossana Vasilakopoulos, Thodoris C. Jeong, Youn Cheol Lee, Hyojoon Rogers, Simon Sakellariou, George Allgaier, Jürgen Takano, Atsushi Brás, Ana R. Chang, Taihyun Gooßen, Sebastian Pyckhout-Hintzen, Wim Wischnewski, Andreas Hadjichristidis, Nikos Richter, Dieter Rubinstein, Michael Vlassopoulos, Dimitris Viscosity of Ring Polymer Melts We have measured the linear rheology of critically purified ring polyisoprenes, polystyrenes, and polyethyleneoxides of different molar masses. The ratio of the zero-shear viscosities of linear polymer melts η<sub>0,linear</sub> to their ring counterparts η<sub>0,ring</sub> at isofrictional conditions is discussed as a function of the number of entanglements <i>Z</i>. In the unentangled regime η<sub>0,linear</sub>/η<sub>0,ring</sub> is virtually constant, consistent with the earlier data, atomistic simulations, and the theoretical expectation η<sub>0,linear</sub>/η<sub>0,ring</sub> = 2. In the entanglement regime, the <i>Z</i>-dependence of ring viscosity is much weaker than that of linear polymers, in qualitative agreement with predictions from scaling theory and simulations. The power-law extracted from the available experimental data in the rather limited range 1 < <i>Z</i> < 20, η<sub>0,linear</sub>/η<sub>0,ring</sub> ∼ <i>Z</i><sup>1.2±0.3</sup>, is weaker than the scaling prediction (η<sub>0,linear</sub>/η<sub>0,ring</sub> ∼<i> Z</i><sup>1.6±0.3</sup>) and the simulations (η<sub>0,linear</sub>/η<sub>0,ring</sub> ∼ <i>Z</i><sup>2.0±0.3</sup>). Nevertheless, the present collection of state-of-the-art experimental data unambiguously demonstrates that rings exhibit a universal trend clearly departing from that of their linear counterparts, and hence it represents a major step toward resolving a 30-year-old problem. polymer;atomistic simulations;isofrictional conditions;Ring Polymer MeltsWe;rings exhibit;ring polyisoprenes;counterpart;data;range 1;entanglements Z;prediction;entanglement regime;ring viscosity;molar masses 2016-02-18
    https://acs.figshare.com/articles/journal_contribution/Viscosity_of_Ring_Polymer_Melts/2366737
10.1021/mz400344e.s001