From these calculations, we can conclude that even the very complicated system like Polyelectrolyte brush can be tackled by the DFT framework. The DFT framework that has been used here, perfectly predicts the Manning condensation. This prediction is very surprising because we got it by solving a set of complicated coupled equations. When a physical phenomenon is clearly seen in the result of a theoretical method, we can rely on this method for other systems. The depletion of the monomers from the surface and the Manning condensation are two key effects that we must consider about the Polyelectrolyte brushes. The former suggests that we can move monomers away from the surface by tuning the Bjerrum length, which is very nice effect and the latter tells us that the Manning condensation is the direct result of the mathematical equations. This might appear easy but the fact is that setting up the equations and solving them such that a real physical phenomenon is captured is a very hard task. Therefore, the DFT is a useful theoretical tool that can be used for any many body system. Its results are reliable and could be used for possible new technologies.