(a)
z∕σ
Figure 7.6: Comparison of the total segment density profiles of the confined (a) 4-
segment linear (dashed curves) and 3-arm star (solid curves) polymer fluids at ηaυg = 0.1
(gray curves), and 0.3 (black curves), (b) 25-segment linear (dot-dashed curves), 4-arm star
(dashed curves), and 3-arm star (solid curves) polymer fluids at ηaυg = 0.1 (gray curves),
and 0.3 (black curves). In fig. (b), the profiles of the 3-arm and 4-arm star polymer fluids
almost overlap each other.
comprises the articulation segment and the segment in each arm directly bonded to it.
To test modified iSAFT, the results for star polymer are compared with the simulation
results from Yethiraj and Hall [265]. The theoretical results are in agreement with
the simulation results demonstrating the predictive capabilities of modified iSAFT.
The conformations of both star and linear polymer chains have to constrained for
the mid-segments of the chains to be near to the surface, hence the density of mid-
segments near the surface is lower than that of the end-segments. However, the
constraint is even severe in the case of the star polymer. Thus the average density
of the mid-segments of the star polymer near the surface is considerably lower than
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