Figure 7.8: Compressibility factors of the bulk star polymer fluids, (a) 3-arm star
polymers with m = 3 (∙) and 5 (à), and (b) 4-arm star polymers with m = 3 (∙) and 5
end-segments comprise all the arm segments. Density of the end-segments for both
the molecular topologies are higher near the surface compared to the mid-segments.
On the contrary, densities of the mid-segments are enhanced at z = 1 σ. Both the
end- and mid-segment densities of the linear polymer near the surface are higher than
those of the 3-arm star polymer, due to higher conformational restriction on the star
polymer to pack against the surface. This is also observed in figures 7.7c and d, where
the average end- and mid-segments densities near the surface of both the 3-arm and
4-arm star polymers are lower than that of the linear polymer. Comparison of the
end- and mid-segments density profile of the star polymer fluids themselves, shows
that as the number of arms in the star polymer increases (keeping the total number of
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