We present experiments and theory on the melt dynamics of monodisperse entangled polymers of H-shaped architecture. Frequency-dependent rheological data on a series of polyisoprene H-polymers are in good agreement with a tube model theory that combines path-length fluctuation (like that of star polymer melts) at high frequency, with reptation of the self-entangled “cross-bars” at low frequencies (like that of linear polymer melts). We account explicitly for mild polydispersity. Nonlinear step-strain and transient data in shear and extension confirm the presence of a relaxation time not seen in linear response, corresponding to the curvilinear stretch of the cross-bars. This time is very sensitive to strain due to the exponential dependence of the branch-point friction constants on the effective dangling path length. Strain-induced rearrangements of the branch points are confirmed by small-angle neutron scattering (SANS) on stretched and quenched partially deuterated samples. We develop an extension of melt-scattering theory to deal with the presence of deformed tube variables to interpret the SANS data.

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. (2011) 'Linking models of polymerization and dynamics to predict branched polymer structure and ow. ', Science., 333 (6051). pp. 1871-1874. Further information on publisher's website:http://dx.doi.org/10.1126/science.1207060 Publisher's copyright statement: This is the author's version of the work. It is posted here by permission of the AAAS for personal use, not for redistribution. The denitive version was published in Science 333/6051, http://dx.doi.org/10.1126/science.1207060Additional information: Use policyThe full-text may be used and/or reproduced, and given to third parties in any format or medium, without prior permission or charge, for personal research or study, educational, or not-for-prot purposes provided that:• a full bibliographic reference is made to the original source • a link is made to the metadata record in DRO • the full-text is not changed in any way The full-text must not be sold in any format or medium without the formal permission of the copyright holders.Please consult the full DRO policy for further details. One of the long-standing fundamental challenges to soft matter science is the quantitative connection between molecular topology and dynamics of branched entangled polymers. The motivation arises from both the universality of the physics (1) and the experimental and