Scaling argument for chain stretching

The linear relation between force and end-to-end distance can also be 

An elongated chain is only stretched on its largest length scales. Inside the tension blob, the conformation of the chain is essentially unperturbed by the 

The stretched polymer is subdivided into sections of g monomers each. We assume that these sections are almost undeformed so that the mean-square projection of the end-to-end vector of these sections of g monomers onto any of the coordinate axes obeys ideal chain statistics [Eq. (2.83)]  

There are Njg such sections and in the direction of elongation they are assumed to be arranged sequentially  

This can be solved for the size of the unperturbed sections and the number of monomers g in each section  

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