  We consider a general discrete model for heterogeneous semiflexible polymer
chains. Both the thermal noise and the inhomogeneous character of the chain
(the disorder) are modeled in terms of random rotations. We focus on the
quenched regime, i.e., the analysis is performed for a given realization of the
disorder. Semiflexible models differ substantially from random walks on short
scales, but on large scales a Brownian behavior emerges. By exploiting
techniques from tensor analysis and non-commutative Fourier analysis, we
establish the Brownian character of the model on large scale and we obtain an
expression for the diffusion constant. We moreover give conditions yielding
quantitative mixing properties.
