Dimer formation as associated block-copolymers

The first system we study is a mixture of R Ai and R Bi chains, each carrying a functional group A or B at one end. Diblock copolymers are formed by the end-to-end association (hetero-dimerization) [1,2]. End groups A and B are assumed to be capable of forming pairwise bonds A-B by thermoreversible hetero-association. The hydrogen bond between acid and base pair is the most important example of this category. 

Fet n=n, 4 -I- be the total number of the statistical units on a block copolymer chain, 

Associated diblock copolymer formed by a pairwise bond between the end groups. 

The logarithmic derivatives of x and y yield specific forms of the /c-functions for the dimerization 

Let us consider the free energy (6.2) of the dimer formation. The conformational free energy appears because the entropy of disorientation is reduced when two chains are combined. If we use the lattice-theoretical entropy of disorientation (2.90), we have 

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