For a linear, freely rotating polymer molecule, the total extended chain length L depends...

For a linear, freely rotating polymer molecule, the total extended chain length L depends on the bond length between chain atoms d, the total number of bonds in the molecule N, and the angle between adjacent backbone chain atoms θ, as follows:

  (4.9)

Furthermore, the average end-to-end distance r for a randomly coiled polymer molecule such as that in Figure 4.6 is equal to

  (4.10)

A linear polytetrafluoroethylene has a number average molecular weight of 500,000 g/mol; compute average values of L and r for this material.

Figure 4.6 Schematic representation of a single polymer chain molecule that has numerous random kinks and coils produced by chain bond rotations.