6. Consider an ideal polyelectrolyte chain consisting of N^ monomers of size b and net charge on the chain Q=efN where f is the fraction of Kuhn monomers bearing a charge. Using the mean-field treatment of Flory, obtain the expression of equilibrium chain size, R as a function of temperature. [Hint: The electrostatic energy of the chain is Q2/(R). where is solvent dielectric constant.] [3]