111 research outputs found
Soft Confinement for Polymer Solutions
As a model of soft confinement for polymers, we investigated equilibrium
shapes of a flexible vesicle that contains a phase-separating polymer solution.
To simulate such a system, we combined the phase field theory (PFT) for the
vesicle and the self-consistent field theory (SCFT) for the polymer solution.
We observed a transition from a symmetric prolate shape of the vesicle to an
asymmetric pear shape induced by the domain structure of the enclosed polymer
solution. Moreover, when a non-zero spontaneous curvature of the vesicle is
introduced, a re-entrant transition between the prolate and the dumbbell shapes
of the vesicle is observed. This re-entrant transition is explained by
considering the competition between the loss of conformational entropy and that
of translational entropy of polymer chains due to the confinement by the
deformable vesicle. This finding is in accordance with the recent experimental
result reported by Terasawa, et al.Comment: 5 pages, 3 figure
Epitaxial Transition from Gyroid to Cylinder in a Diblock Copolymer Melt
An epitaxial transition from a bicontinious double gyroid to a hexagonally
packed cylinder structure induced by an external flow is simulated using
real-space dynamical self-consistent field technique. In order to simulate the
structural change correctly, we introduce a system size optimization technique
by which emergence of artificial intermediate structures are suppressed. When a
shear flow in [111] direction of the gyroid unit cell is imposed, a nucleation
and growth of the cylinder domains is observed. We confirm that the generated
cylindrical domains grow epitaxially to the original gyroid domains as gyroid
cylinder . In a steady state under the shear
flow, the gyroid shows different reconnection processes depending on the
direction of the velocity gradient of the shear flow. A kinetic pathway
previously predicted using the self-consistent field theory where three fold
junctions transform into five fold junctions as an intermediate state is not
observed.Comment: 24 pages, 14 figures, submitted to Macromolecule
Effects of Changes in the Chain Conformation on the Kinetics of Order-Disorder Transitionjs in Block copolymer Melts
See Also: Erratum: Toshihiro Kawakatsu, Erratum: Effects of changes in the chain conformation on the kinetics of order-disorder transitions in block copolymer melts [Phys. Rev. E 56, 3240 (1997)], Phys. Rev. E 57, 6214 (1998)
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