The name is absent

10
1

0.1
βf∕(p_g³'²A)

0.01

0.001

0.0001

W⁵

q

Figure 6.9: Interaction force between the two grafted monolayers in the absence of free
polymer scaled by p_g^¹ as a function of the compression ratio for N_g = 51 and p_gσ² = 0.1
(φ), N_g — 101 and ρ_gσ² = 0.1 (■), N_g = 151 and p_gσ² = 0.1 (∙), N_g = 101 and p_gσ² =
0.03 (A), N_g = 101 and p_gσ² = 0.01 (▼).

chains are athermal, they are implicitly in good solvent condition. Figure 6.10a shows
the segment density profiles of the grafted and free polymers for N_g — 101,=
0.1, Nf = 100, and Pfσj = 0.25 when the grafted monolayers have no interaction. The
free polymer decreases the unperturbed brush height from Ho = 55 σ in the absence of
free polymer to about 44 σ in the presence of it. Each monolayer interpenetrates the
free polymer to a certain extent after which the free polymer reaches its bulk density.
The monolayers start interacting as the separation is reduced. In addition to the
penetrating the free polymer the monolayers themselves interpenetrate each other.
In doing so, they expel the free polymer between them and the density of the free
polymer decreases, as shown in figs. 6.10b and c. Eventually, at low enough separation
almost all the free polymer leaves the gap between the monolayers. Figure 6.11a shows
the interaction force between the two grafted monolayers as they approach each other.

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