Molecular Rheology of Comb Polymer Melts. 1. Linear Viscoelastic Response

We present experiments and theory on the melt dynamics of monodisperse entangled polymers of comb-shaped architecture. Frequency-dependent rheological data on a series of comb polymers are in good agreement with a tube-model theory that combines star polymer melt behavior at high frequency with modified linear polymer reptation behavior at low frequencies. Taking into account mild polydispersity and by incorporating the high-frequency Rouse modes, we are able to model quantitatively the entire frequency range. Qualitatively distinct dynamical features of the comb architecture are compared to those of the simpler star and H-topologies.