The name is absent

lamella are constrained to adjust within the confining space. The free energy of these
copolymer systems is a balance of free energies due to the formation of interfaces
between the lamella of the two blocks, stretching of the copolymer chains to form
the lamellar structure and interactions of the blocks with the confining surfaces.
Symmetric surfaces are considered, where both the surfaces preferentially attract the
segments in the A block of the copolymer and repel the segments in the B block.
The interplay of the three free energies can lead to a number of lamellar structures
between the two surfaces. Symmetric lamellar structures are the ones where both the
surfaces are covered with the energetically favorable A block. There are integer ‘n’
number of lamella or even number of A - B interfaces. In anti-symmetric lamellar
structures, one of the surfaces is covered with energetically favorable A block and
the other with the energetically unfavorable B block. There are half-integer ^ζn ÷
I’ number of lamella or odd number of A - B interfaces. These parallel lamellar
structures are designated as bj! where v is the number of interfaces. Hence, ʃɪ
denotes the symmetric lamellar phase with n lamella and T2n₊1 denotes the anti-
symmetric lamellar phase with n + ɪ lamella. It has been found that when both
the surfaces have weak/по preference for either of the blocks the Iamellas are aligned
perpendicular to the two surfaces [138, 135, 151], L^^l phase. In this case the copolymer
can attain its bulk equilibrium lamellar period Db-

Consider a symmetric diblock copolymer, N = 8 and e∕kT = 0.289 confined
between two planar surfaces with e_w∕kT = 0.1. Figure 5.5 shows the symmetric L^_n

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