Growth of two dimensional domains in copolymer thin films

Ausserré, Dominique; Chatenay, D.; Coulon, G.; Collin, Blaise P.

doi:10.1051/jphys:0199000510220257100

Cited by 45 publications

(49 citation statements)

References 5 publications

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“…If higher magnification micrographs are acquired along a constant g s track, the familiar progression from smooth surface to islands to co-continuous to holes back to a smooth surface as a function of h is found. [3,4,[19][20][21] Likewise, if a series of micrographs are obtained from a constant h path, the morphology is observed to change from symmetric to antisymmetric with the nature of the surface patterns formed depending on h. [14] An example of this morphology change is shown in Figure 3 where AFM images of an M ¼ 51k block copolymer film acquired at h % 71 nm (2.37 L o ) are presented. The images were obtained in tapping mode and have a common height scale (full range 50 nm) where the brighter color indicates tall features and the dark color indicates holes on the film surface.…”

Section: Resultsmentioning

confidence: 99%

“…Previous work has shown that when these polymers are cast as thin films, a preferential surface interaction between one of the blocks and the substrate causes the lamellae to become oriented parallel to the substrate. [2,[17][18][19][20][21][22] These films are smooth when the film thickness (h) is an integral multiple of the lamella thickness (L o ) but have an incomplete surface lamella that forms islands or holes of L o when the thickness deviates from this value. [2][3][4] In addition to film thickness, the substrate surface energy (g s ) may affect the morphology of the thin film.…”

Section: Introductionmentioning

confidence: 99%

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Combinatorial Mapping of Surface Energy Effects on Diblock Copolymer Thin Film Ordering

Smith

Sehgal

Douglas

et al. 2003

Macromol. Rapid Commun.

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Combinatorial gradient techniques are used to map the morphology dependence of thin symmetric diblock copolymer films on film thickness and substrate surface energy. An inversion from symmetric to anti‐symmetric lamellar morphology occurs with a progressive change in surface energy. An intermediate neutral region is found between these limiting types of ordering. The width ω of this transitional energy range scales as a power of copolymer mass M, ω ∝ M1.9.Optical photograph of a combinatorial map of the thin‐film block‐copolymer morphology on a film thickness and surface energy gradient. Island and holes on the surface scatter light causing the film to appear cloudy (lighter in color) in the areas where they exist. The darker areas do not have surface features and do not scatter light.magnified imageOptical photograph of a combinatorial map of the thin‐film block‐copolymer morphology on a film thickness and surface energy gradient. Island and holes on the surface scatter light causing the film to appear cloudy (lighter in color) in the areas where they exist. The darker areas do not have surface features and do not scatter light.

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Section: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Combinatorial Mapping of Surface Energy Effects on Diblock Copolymer Thin Film Ordering

Smith

Sehgal

Douglas

et al. 2003

Macromol. Rapid Commun.

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“…A step edge between the L ν ∥ and L ν+2 ∥ phases will typically involve ν continuous monolayers plus one semi-infinite bilayer as depicted schematically in Figure 1. Ausserréet al 5 initially argued that the bilayer should exist one monolayer below the air surface, rather than on top as in Figure 1. Furthermore, they suggested that the lateral width of the step should be comparable to the bilayer thickness, L 0 , but AFM measurements by Maaloum et al 13 found the steps to be much broader.…”

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confidence: 99%

Step Edges in Thin Films of Lamellar-Forming Diblock Copolymer

et al. 2012

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Self-consistent field theory (SCFT) is used to study the step edges that occur in thin films of lamellar-forming diblock copolymer, when the surfaces each have an affinity for one of the polymer components. We examine film morphologies consisting of a stack of ν continuous monolayers and one semi-infinite bilayer, the edge of which creates the step. The line tension of each step morphology is evaluated and phase diagrams are constructed showing the conditions under which the various morphologies are stable. The predicted behavior is then compared to experiment. Interestingly, our atomic force microscopy (AFM) images of terraced films reveal a distinct change in the character of the steps with increasing ν, which is qualitatively consistent with our SCFT phase diagrams. Direct quantitative comparisons are not possible because the SCFT is not yet able to probe the large polymer/air surface tensions characteristic of experiment. ■ INTRODUCTIONThe behavior of block copolymer melts on solid substrates has received considerable attention over the last two decades motivated by a wide range of applications. 1−3 Not surprisingly, the earliest work 4−8 involved the simplest conceivable system, thin films of symmetric AB diblock copolymer on flat substrates. In the bulk, symmetric diblock copolymer forms a lamellar phase of alternating A-and B-rich domains, where each period, L 0 , consists of two monolayers. The main effect of confining the diblock copolymer to a thin film is to orient the domains. When the substrate and air surfaces of the film each have an affinity for one of the polymer components, the lamellae orient in the plane of the film, thereby forming a parallel lamellar (L ν ∥ ) phase consisting of ν diblock monolayers. Because of the strong tendency to maintain the preferred domain size of the bulk, the film height is quantized, H ≈ L 0 ν/ 2. Even values of ν are selected when the two surfaces have an affinity for the same component, and odd values occur when the two surfaces have opposite affinities. Usually the amount of material cast on the substrate is incommensurate with the preferred domain size, which leads to macrophase separation into thin and thick regions (i.e., terraces) separated by steps of height L 0 . The topography of the air surface changes from islands to a bicontinuous network to holes as the area of the thicker region increases. 4 The behavior becomes particularly interesting with the formation of elaborate terraced structures, when droplets 9−11 or rings 12 of diblock copolymer are deposited on the substrate.The presence of step edges separating different film thicknesses is ubiquitous in block copolymer films, and yet they have received relatively little theoretical attention. A step edge between the L ν ∥ and L ν+2 ∥ phases will typically involve ν continuous monolayers plus one semi-infinite bilayer as depicted schematically in Figure 1. Ausserréet al. 5 initially argued that the bilayer should exist one monolayer below the air surface, rather than on top as in Figure 1. Fu...

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“…The appearance of hole and island patterns as a function of the film thickness is a well-known phenomenon. [33,34] However, optical and microscopic investigations of thickness gradients of polystyrene/poly-(methyl methacrylate) (PS/PMMA) film libraries revealed additionally spinodal morphologies and broad smooth regions ( Figure 10). [35,36] …”

Section: Block Polymer Ordering Behavior and Phase Behaviormentioning

confidence: 99%

High‐Throughput Experimentation in Organic Coating and Thin Film Research: State‐of‐the‐Art and Future Perspectives

Schmatloch¹,

Bach²,

Benthem³

et al. 2003

Macromol. Rapid Commun.

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Summary: The success of automated and parallel drug‐discovery workflows in pharmaceutical research has sparked similar developments in materials science. This contribution provides an overview of published high‐throughput experimentation work in the area of polymeric coatings and thin films. Methodological aspects, experimental examples, and remaining challenges are discussed.Robotic system (GE) for crosshatch application.magnified imageRobotic system (GE) for crosshatch application.

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Growth of two dimensional domains in copolymer thin films

Cited by 45 publications

References 5 publications

Combinatorial Mapping of Surface Energy Effects on Diblock Copolymer Thin Film Ordering

Combinatorial Mapping of Surface Energy Effects on Diblock Copolymer Thin Film Ordering

Step Edges in Thin Films of Lamellar-Forming Diblock Copolymer

High‐Throughput Experimentation in Organic Coating and Thin Film Research: State‐of‐the‐Art and Future Perspectives

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