Phase Equilibria in Macromolecular Systems

Having specified our model we want to estimate the number of distinct polymer configurations on the lattice  

We first approximate the probability that a particular monomer is placed in a cell next to its polymer-neighbor monomer via 

Here q is the coordination number of the lattice. This is the number of neighbors each cell has. On a square lattice g = 4 on a simple cubic lattice q = 6. This means that if we have a polymer partially laid out on the lattice and we put the next monomer, of which we know that it is the neighbor in the polymer, down on the lattice blindfolded, then there are g -1 good cells compared to N cells total. Of course we neglect occupancy of the cells by previous monomers—a truly crude approximation. Nevertheless we approximate the above probability as 

The justification for this clearly important formula will be given in the next chapter. Here we merely consider its consequences. Using the Stirling formula, i.e. 

Before we discuss this, we compute the entropy of mixing given by 

---

Phase Equilibria in Macromolecular Systems NaPJ(RTcPc)... 

---