Effective calculations set of chains with two-body interactions

EFFECTIVE CALCULATIONS SET OF CHAINS WITH TWO-BODY INTERACTIONS 

1 Interaction of two chains in solution second virial coefficient 

As was shown above [see (10.5.7)], the expansion of the osmotic pressure up to second-order reads 

By using the perturbation techniques described previously, we can expand (A, B) in powers of the interaction parameter b 

we observe that, among the diagrams associated with (A, B), those in which only one interaction line joins A and B, give a contribution which is just equal to — b2 A)2Z(B) this appears on Fig. 10.26, when proper account is taken of the rules given in Section 3.2.2. Now, let A, B) be the sum of the contributions of the diagrams in which at least two interaction lines join A and B. We have 

---