Defect Dynamics in Mesophases

Viñals, Jorge

doi:10.1143/jpsj.78.041011

Cited by 4 publications

(4 citation statements)

References 51 publications

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“…Although the values of η in their studies are different, they are all around 0.25. These results are well consistent with theoretical predictions of Vega et al 40 and Vinals et al 41 The value of η is supposed to depend on the strength of phase separation, thermal noise, and specific types of length scales studied. 40 Anyhow, the evolution of correlation length as time obeys a universal power law.…”

Section: Introductionsupporting

confidence: 91%

Kinetics of lamellar formation on sparsely stripped patterns

Xie

Zhang

et al. 2013

The Journal of Chemical Physics

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Chemical epitaxy based on the self-assembly of block copolymers is viewed as a promising technique to achieve ordered patterns on a large scale. Herein, we study the kinetics of lamellar formation of block copolymers under the direction of sparsely stripped patterns using cell dynamics simulations of the time-dependent Ginzburg-Landau theory. First, a scaling law is unveiled with the ordering time of lamellae, tp, with respect to the multiples between the periods of lamellae and stripe patterns, which is consistent with the power law evolution of the correlation length existing in the bulk phase of lamellae. Second, the tolerative windows of perfect order, with deviation from integer multiples, are also estimated from the aspect of kinetics. The results of the ordering time and tolerative windows are of great interest for relevant experiments or applications. Finally, a two-stage evolution is explored during the pattern formation of chemical epitaxy by probing into the evolution of defects, which is of fundamental interest for us to understand the coarsening kinetics of block copolymers under the direction of chemical patterns.

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Section: Introductionsupporting

confidence: 91%

Kinetics of lamellar formation on sparsely stripped patterns

Xie

Zhang

et al. 2013

The Journal of Chemical Physics

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“…For example, the grain boundary between lamellae with mismatch orientations usually appears in the lamellar phase; the defects of dislocation and disclinations can destroy the translational and orientational order in thin films of hexagonally arranged cylinders (or spheres) formed by BCPs. Vinals and coworker have performed a series of research on grain boundary dynamics and defect dynamics in bulk lamellar phase. − The study of both experiments ,, and computer simulations , shows that the orientation correlation length grows with time according to a power law with an exponent of 1/4 in cylinder- or sphere-forming system. Therefore, for macroscale thin films (from micrometers to millimeters) on an uniform substrate, the relaxation time to annihilate all defects is infinitely long.…”

Section: Introductionmentioning

confidence: 99%

Ordering Dynamics of Directed Self-Assembly of Block Copolymers in Periodic Two-Dimensional Fields

Qiu

Yang

et al. 2010

Macromolecules

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The ordering dynamics of directed self-assembly of cylinder-forming diblock copolymers is studied by cell dynamics simulations. The directing field, mimicking chemically or topologically patterned substrates, is in the form of hexagonally arranged potential wells attractive to minority blocks. Time evolution of the defect concentration is used to characterize the ordering dynamics of the self-assembled cylindrical structures of the block copolymers. When the period of the external potential, L s , is a small integer multiple of the cylinder-to-cylinder distance, L 0 , of the block copolymer microphase, the defect concentration decays exponentially. The defect annihilation becomes slower as L s is increased, and eventually, the exponential decay law is broken. When the ratio L s /L 0 is a square root of an integer, large polycrystalline grains with different orientations are observed. The results are consistent with available experimental and theoretical results.

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“…In this process, domains with long-range order (grains) grow via the annihilation of defects, such as dislocations and grain boundaries between domains with different lattice orientation [58][59][60][61][62][63][64][65][66][67][68]. During domain growth, the defect-annihilation rate slows down continuously as the average distance between dislocations and between grain boundaries increases [69,70].…”

Section: Introductionmentioning

confidence: 99%

Scaling properties of ageing orientation fluctuations in stripe phases

Riesch¹,

Radons²,

Magerle³

2017

Interface Focus.

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We investigate the non-equilibrium dynamics of an ordered stripe-forming system free of topological defects. In particular, we study the ageing and the coarsening of orientation fluctuations parallel and perpendicular to the stripes via computer simulations based on a minimal phase-field model (model B with Coulomb interactions). Under the influence of noise, the stripe orientation field develops fluctuations parallel to the stripes, with the dominant modulation length λ* increasing with time as λ* ∼ and the correlation length perpendicular to the stripes increasing as ∼. We explain these anisotropic coarsening dynamics with an analytic theory based on the linear elastic model for stripe displacements first introduced by Landau and Peierls. We thus obtain the scaling forms and the scaling exponents characterizing the correlation functions and the structure factor of the stripe orientation field. Our results reveal how the coarsening of orientation fluctuations prevents a periodically modulated phase free of topological defects from reaching equilibrium.

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Defect Dynamics in Mesophases

Cited by 4 publications

References 51 publications

Kinetics of lamellar formation on sparsely stripped patterns

Kinetics of lamellar formation on sparsely stripped patterns

Ordering Dynamics of Directed Self-Assembly of Block Copolymers in Periodic Two-Dimensional Fields

Scaling properties of ageing orientation fluctuations in stripe phases

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