Here, A is the surface area and k B T is the thermal energy. The first term in this grand potential functional is the entropic elasticity and it accounts for the elasticity of the chains arising from entropy of monomers. The second term refers to the excluded volume interactions between the monomers where b is the second Virial coefficient and its value for the spherical particles in good solvent is around 2.09 a 3 where a is the Kuhn length and it is a measure of monomers size. The third and fifth terms refer to the constraint that the total number of monomers and counterions are fixed, respectively. This is done by using Lagrange multipliers µ p for monomers and µ