Reptation model basic equations

One has no results for this case derived consequently from the basic equations (7.6) with local anisotropy. Instead, to find conformational relaxation equation, we shall use the Doi-Edwards model, which approximate the large-scale conformational changes of the macromolecule due to reptation. The mechanism of relaxation in the Doi-Edwards model was studied thoroughly (Doi and Edwards 1986 Ottinger and Beris 1999), which allows us to write down the simplest equation for the conformational relaxation for the strongly entangled systems... 

III.3.2 Biasing the Reptation Model The reptation process is fully defined by the four elements present in the basic stochastic equations (8) and (9). These are the probabilities that the next Jump will be made towards the end of the tube, the time duration and the length 0 =0 of this Jump, and finally the vector c( ) giving the properties of the new tube section created by this Jump. The fact that p =i, x =XBrown (c(0>=0 in absence of a field reflects the fact that we then have Brownian motion. The tube concept and the assumption of a constant pore size a are implicit in Eq.(8). 

---