The name is absent

of preferential confining surfaces. However, these morphologies were found to be rel-
atively unstable to perpendicular morphologies. Hence, although these morphologies
are kinetically favored, they are thermodynamically unstable for symmetric diblock
copolymers. Similar conclusions are drawn from other SCFT studies by Tang [127]
and Geisinger et. al. [141, 142].

Density functional theories (DFTs) also have recently been applied to study inho-
mogeneous polymer systems. As mentioned earlier, these theories retain the monomer
or statistical segment length-level information rather than the coarse-grained repre-
sentation of the polymer. Both the long-ranged structural quantities which depend
on the chain connectivity as well as the short-ranged quantities which depend upon
the local packing are well described by the DFTs [143, 144]. On the contrary, mean
field and SCF theories neglect the fluctuations in the local composition from an
average value. DFTs include the compressibility effects important for liquid state
theories which are missed by mean field and SCF theories. The natural formalism
of the DFTs is the grand canonical ensemble where the fluctuations in the number
of polymer chains in the system keep the chemical potential constant. Thus the sys-
tem is compressible and phase transitions can include fluctuations in density of the
system. In case of confined copolymer films the compressibility, local density fluctu-
ations and the packing effects are important especially near to the confining surfaces
and the interfaces of the two blocks, as demonstrated by Geisinger et. al. [141, 142]
through comparisons between Monte Carlo simulations and SCF calculations. Molec-

115

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