Test of tube dilation picture at short times through dynamic scattering and viscoelastic experiments

Abstract

The dynamic tube dilation (DTD) concept is tested for the viscoelastic relaxation function μ(t) and the coherent intermediate scattering function Ic(q,t) (q = the wave vector) of highly entangled linear chains. The analysis made for Ic and μ involves only the Gaussian nature of the chain and no other details of the chain dynamics. Simple relationships are derived between Ic(q,t) and μ(t) for the two case of the fixed and dilated tubes. The range of time considered is longer than the Rouse time τR for contour length fluctuation but smaller than the terminal viscoelastic relaxation time τG, and the range of μ(t) is 1 > μ(t) > 0.5. The relationships are significantly different for the two cases. This difference should enable a test of the DTD picture at short t (but still longer than τR) through comparison of the Ic(q,t) and μ(t) data.