Kinetic Pathway of Gyroid-to-Cylinder Transition in Diblock Copolymer Melt under an Electric Field

Abstract

Gyroid-to-cylinder transition in a diblock copolymer melt under an electric field is studied by real-space dynamical self-consistent-field theory. Starting from an equilibrium gyroid structure, we apply an electric field along [111], [11̄0], and [112̄] directions of the conventional unit cell of the gyroid structure. Under sufficiently high value of the electric field, an epitaxial transition to cylinders occurs. Contrary to the case of a similar transition under the shear flow, we observe 5-fold connections as intermediates in the transition. We found a critical behavior of the lifetime of the initial gyroid structure, which can be accounted for using the mean-field argument. Numerically obtained scattering function explains the unclarified intermediates experimentally observed in the thermal relaxation of a sheared gyroid.

Dynamic Self-Consistent Field Theories for Polymer Blends and Block Copolymers

“…6), we observe uniform transition from the initial gyroid structure to the final cylindrical structure. We confirmed that this uniform nature of the intermediate structure is not due to the effect of the system size optimization 19 as in the case of the shear flow. The main difference between the shear flow case and this electric field case is the fact that the external field has two characteristic directions in the shear flow case, i.e.…”

“…5,9 There have been considerable works for the dynamic extensions of the SCF theory to the diffusion regime, and various simulation techniques and knowledge have been accumulated. 3,5,10 For example, dynamics of microphase separation of diblock copolymer melts, 10,11 phase behavior of complex polymeric systems, 12,13 dynamics of block copolymers under external constraints and under external fields [14][15][16][17][18][19][20][21][22] Contrary to the situation for these dynamic SCF theories in the diffusion regime, studies for the viscoelastic regime have not yet been well developed from the viewpoint of the SCF theory. Actually, there have been several trials to study such viscoelastic regime using dynamic SCF theories.…”

FIB-SEM and TEMT Observation of Highly Elastic Rubbery Material with Nanomatrix Structure

“…[1][2][3][4][5][6] Thus, we have proposed a nanomatrix structure 7 to solve the unavoidable problem of the block-and graft-copolymers, i.e. the grain boundary.…”

Beyond Orientation: The Impact of Electric Fields on Block Copolymers

“…Initial theoretical calculations by Matsen in 1998 suggested a low-energy pathway for the GYR → CYL transition, [ [ 85 ] which was supported by simulations, and experimentally observed by Schmidt et al in 2010 [86][87][88] (Figure 4 b). Figure 4 a shows calculated structures for the transition from CYL → GYR and vice versa.…”