The name is absent

hard walls, this reduces to the sum of the contact densities of the grafted and free
polymer chains at the surface at z = 0 (see appendix for derivation).

Hence, the structure of the grafted polymer chains (and the free polymer) has to be
calculated first before calculating the force of interaction between them. To calculate
the segment density profiles numerically, the computational domain is divided into
equally spaced grid points along the dimension normal to the surface (z). The density
profiles are solved using Picard’s iteration method. All the integrations are calculated
using the trapezoidal rule.

6.3 Results and discussion

6.3.1 Structure of polymer brush in the absence of free poly-
mer solvent

Modified iSAFT is used to calculate the structure of grafted monolayer (or polymer
brushes) in the absence of free polymer solvent. To test the accuracy of modified
iSAFT, the results are compared with the simulation results of Grest and Murat [230].
In these simulations, no solvent molecules were explicitly present. Instead, inter-
molecular attractions are incorporated to mimic the effect of the quality of solvent
implicitly. The inter-molecular attractions are modeled by the Lennard-Jones (LJ)
potential.

u_ij(r) = u⅛^j(r) - u⅛^j(r_c),                       (6.24)

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