Monte Carlo simulations of diblock copolymer thin films confined between two homogeneous surfaces

Wang, Qiang; Yan, Qiliang; Nealey, Paul F.; Pablo, Juan J. de

doi:10.1063/1.480639

Cited by 161 publications

(235 citation statements)

References 17 publications

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“…4,5,[8][9][10][11][12][13][14][15][16][17][18] Since in this case both A and B blocks are present near the surfaces, the surface-block interfacial energy can be relatively high if the surfaces are not completely neutral, which is often the case in experiments. It has been pointed out 5,[9][10][11][17][18][19] that in perpendicular lamellae confined between two homogeneous and ͑weakly͒ preferential surfaces, undulations of the A-B interface can be caused by the surface-induced segregation of preferred blocks near the surfaces; these could reduce the surface-block interfacial energy and thus stabilize the perpendicular morphology.…”

Section: Introductionmentioning

confidence: 98%

“…5,21 The simulation results have served as a a͒ guide to propose plausible solutions for theoretical calculations. In this work we examine the ability of a simple phenomenological theory to describe the behavior of symmetric diblock copolymer thin films confined between two hard surfaces.…”

Section: Introductionmentioning

confidence: 99%

“…[1][2][3][4][5][6][7][8][9][10][11] This reduces the surface-block interfacial energy. In the case of parallel lamellae confined between two hard ͑impenetrable͒ surfaces, the confined lamellar period L may vary from the bulk value L 0 to accommodate the frustration between surface separation D and L 0 .…”

Section: Introductionmentioning

confidence: 99%

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Symmetric diblock copolymer thin films confined between homogeneous and patterned surfaces: Simulations and theory

Wang

Nath

Graham

et al. 2000

The Journal of Chemical Physics

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We have investigated the ability of a simple phenomenological theory to describe the behavior of symmetric diblock copolymer thin films confined between two hard surfaces. Prior knowledge of the morphology in the confined films is crucial for applying this theory to predict the phase diagram of such systems. Taking advantage of our observations in Monte Carlo simulations, we use the theory to construct phase diagrams for thin films confined between patterned-homogeneous surfaces, and obtain good agreement with our results of simulations. Two conditions are essential for obtaining long-range ordered perpendicular lamellae: a lower stripe-patterned surface with the surface pattern period L s comparable to the bulk lamellar period L 0 , and an upper neutral or weakly preferential surface. We have also examined the undulation of perpendicular lamellae between two hard surfaces. For the cases of two homogeneous ͑preferential͒ surfaces and patterned-preferential surfaces, our calculations using the phenomenological theory indicate that the amplitudes of the undulation are on the same order of magnitude as observed in our Monte Carlo simulations, and are one order of magnitude larger than previously reported. The theory, however, is unable to capture the shape of the undulation. For the case of patterned-neutral surfaces, we find that an earlier analysis is unable to yield the undulations that would stabilize the perpendicular lamellar morphology. We have addressed this issue and obtained undulations that are consistent with our observations from Monte Carlo simulations.

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Section: Introductionmentioning

confidence: 98%

Section: Introductionmentioning

confidence: 99%

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Symmetric diblock copolymer thin films confined between homogeneous and patterned surfaces: Simulations and theory

Wang

Nath

Graham

et al. 2000

The Journal of Chemical Physics

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“…It should be pointed out that the long-range interactions between the neighboring periods likely lead to artifact microstructures in the bulk simulations when the periodic boundary conditions are selected. 40,41 In our calculations, the periodic boundary conditions are not necessary because the nanoparticle provides a completely closed confinement. Alternatively, this requires the distortion of cylinders in the outer layer to meet commensurability.…”

Section: Resultsmentioning

confidence: 99%

Surface-field-induced microstructures of asymmetric diblock copolymer nanoparticles

Liu

et al. 2011

Polym J

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The microstructures of asymmetric diblock copolymer nanoparticles were investigated using real-space self-consistent field theory. The nanoparticle boundary provides a spherical confinement in which the highly deformable copolymers are forced into a closed and crowded space. The surface-field-induced effects on the microstructures were examined systematically, and a rich variety of novel structures, such as mixtures of distorted cylinders and spherical lamellae, was observed in the copolymer nanoparticles. Investigations of the free energies indicate that the surface-field-induced structural transitions are of the first order. The formation mechanism of the confinement-induced structures was reasonably elucidated, based on the interactions between the polymer chains and confinement boundaries, and on the spherical symmetry from confinements. Our theoretical results are in good agreement with available simulation and experimental observations.

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“…In recent years we have seen a large effort directed toward finding ways to control the phasebehavior and orientation of self-assembled structures [1,2]. Confinement between two solid surfaces [3,4,5,6,7,8,9,10,11,12,13] , shear flow [14], or the use of external electric fields [15,16,17,18,19,20,21,22,23,24,25,26,27] have proved very useful. The use of electric fields is especially appealing, as the field strength scales favorably with the system size.…”

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confidence: 99%

Lamellar Phases in Nonuniform Electric Fields: Breaking the In-Plane Rotation Symmetry and the Role of Dielectric Constant Mismatch

Tsori

2007

Macromolecules

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We consider orientational transitions of lamellar phases under the influence of a spatially nonuniform electric field. The transition between parallel and perpendicular lamellar stackings with respect to the substrate is investigated as a function of the system parameters. The dielectrophoretic energy and the energy penalty for having dielectric interfaces perpendicular to the field's direction are identified as linear and quadratic terms in a free energy expansion in the dielectric constant mismatch. We find that if the dielectric constant mismatch ∆ε is smaller than some critical value ∆εc, parallel lamellar stacking will be realized, no matter how large the voltage difference between electrodes is. At ∆ε > ∆εc, perpendicular stacking will appear if the voltage is high enough. Nonuniform fields remove the in-plane degeneracy present in the more common uniform fields. We therefore calculate the energy of grains of different orientations. The torque acting on the grains leads to the preference of only one orientation. The results have direct implications to block copolymer orientation and to surface patterning on the nanometer scale.

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Monte Carlo simulations of diblock copolymer thin films confined between two homogeneous surfaces

Cited by 161 publications

References 17 publications

Symmetric diblock copolymer thin films confined between homogeneous and patterned surfaces: Simulations and theory

Symmetric diblock copolymer thin films confined between homogeneous and patterned surfaces: Simulations and theory

Surface-field-induced microstructures of asymmetric diblock copolymer nanoparticles

Lamellar Phases in Nonuniform Electric Fields: Breaking the In-Plane Rotation Symmetry and the Role of Dielectric Constant Mismatch

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