Chain dynamics INDEX

One can try to locate a critical polymerisation index above which the data are no longer compatible with a Rouse-like dynamics, Ng = 500, lager than the Ng= 100 value determined from the diffusion measurements in a frozen matrix. This is an illustration of the fact that the two processes. Rouse motion and entangled motion are in competition the slowest process is the one which is indeed observed.When the matrix chains are mobile, the entangled dynamics becomes more rapid than pure reptation, and the Rouse motion can dominate the dynamics for larger molecular weights than when the matrix chains are immobile. 

To stress that the number of chain atoms N is always assumed to be very large, their index will be formally treated as a continuous variable so that, for example, R(/i) will represent the position vector of the /ith atom. Obviously enough, in the dynamic case the time variable will also be added. 

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