Tricritical state. Phase separation region

In a very good solvent, a chain s segments are repelled from each other, which is formalized in the existence of segment excluded volume at the intramolecular level and of polymer coil excluded volume at the intermolecular level. In this case, very long chauns obey the universal scaling laws characteristic of the proximity of the critical point in general-type systems. 

Suppose Ai polymer chains are contained in a box of a volume V. Rach chain is characterized by its Brownian area 

The Lagrangian formalism represents the set of M chains as an action (Duplantior, 

For the model of the system (Equations 3 5), the partition function of Ad chains is defined by Wiener s functional integral with respect to all the conformations of all the chains 

The integral 3 is infinite for continiioiifl chains due to the infinite number of degrees of freedom that is why a regularized statistical integral 

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