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We present a general coarse-grained model for predicting the linear viscoelasic properties of branched polymers from the knowledge of their molecular structure and three viscoelastic parameters, i.e., the Rouse time of an entanglement segment, the plateau modulus, and the entanglement molecular weight. The model uses the ingredients of the tube-based theories of McLeish and co-workers, and its implementation is based on a timemarching algorithm; this conceptual approach was already successfully applied to linear and star polymers, and it is appropriately modified here to account for more complex branched architectures, within the framework of dynamic tube dilation (using the criteria of Graessley). Whereas the molecular physics behind this model is the well-established hierarchical tube-based motion, the new element is a different macromolecular coordinate system and account of the branch points diffusion. With proper account of polydispersity, successful description of a wide range of rheological data of H and pompom polymers is obtained, with the use of the dilution exponent R ) 1 and the parameter p 2 ) 1. The proposed methodology thus represents a generic approach for predicting the linear rheology of branched polymers.

Supramolecular polymers are used in many applications such as adhesives, coatings, cosmetics, and printing. Characterizing the dynamics of such polymers is essential for tailoring user defined properties in products and applications. We present both linear and nonlinear rheological results for a model system of pure poly(n-butyl acrylate), PnBA, homopolymer and four PnBA-poly(acrylic acid), PnBA-PAA, copolymers with different number of AA side groups. The copolymers are synthesized via hydrolysis of the pure PnBA homopolymer. Therefore, all polymers studied have the same backbone length. The number of AA side groups (hydrogen bonding groups) after hydrolysis is determined from NMR measurements. We show that using the theoretical dependency * To whom correspondence should be addressed 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 of modulus and reptation time on the packing length, we can account for the changes in linear viscoelasticity due to transformation of nBA side groups to AA along the backbone. Assuming superposition holds and subtracting out the linear chain rheology from LVE, the hydrogen bonding contribution to LVE is exposed. Hydrogen bonding affects linear viscoelasticity at frequencies below the inverse reptation time. More specifically, the presence of hydrogen bonds causes G and G as a function of frequency to shift to a power law scaling of 0.5. Furthermore, the magnitude of G and G scales linearly with the number of hydrogen bonding groups. The nonlinear extensional rheology shows extreme strain hardening. The magnitude of extensional stress has a strongly nonlinear dependence on the number of hydrogen bonding groups. These results are aimed at uncovering the molecular influence of hydrogen bonding on linear and nonlinear rheology to aid future molecular synthesis and model development.