Unifying Weak- and Strong-Segregation Block Copolymer Theories

Matsen, Mark W.; Bates, Frank S.

doi:10.1021/ma951138i

Cited by 1,750 publications

(2,067 citation statements)

References 69 publications

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“…As shown in Fig. 3, the results of the OK model agree well with the density profiles of SCFT at = 11 ∼ 14, which is consistent with the previous study [13]. However, at ≳ 14, the peak of of the OK model became larger than unity, whereas the SCFT profile became shaper at the interface and flatter at the inside of the lamella domains (e.g., SCFT's profile at = 25 in Fig.…”

Section: Comparison With Scftsupporting

confidence: 90%

Large-Scale Simulations of Directed Self-Assembly with Simplified Model

Yoshimoto

Taniguchi

2013

J. Photopol. Sci. Technol.

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Directed self-assembly (DSA) is considered as a candidate for future patterning technology for semiconductor manufacturing. The DSA utilizes the phase separation of block copolymer and provides further resolution enhancement by the use of chemically and physically pre-patterned surface. In order for DSA to be a viable lithography solution, it is crucial to realize defect-free manufacturing process. In this study, we utilize the so-called Ohta-Kawasaki (OK) model to simulate the morphological defects of block copolymer formed on the chemically and physically pre-patterned surface. The OK model has advantages of the relatively low computational expense, scalability for large-scale simulations, and compatibility to the other simulation models such as self-consistent field theory (SCFT) through common physical properties of the materials. As test cases, we investigated the lamella defects of symmetric diblock copolymer formed on the chemically and physically pre-patterned surface. For the chemically pre-patterned surface, the two-dimensional (2D) dynamic simulations were performed including the thermal fluctuations, and the time evolution of the lamella defects was characterized as a function of the surface interactive parameter. In the three-dimensional (3D) dynamic simulations of the physically pre-patterned surface, effects of the trench width on the formation of the lamella defects was examined. Our preliminary results demonstrate that various types of the DSA lamella defects can be reasonably predicted by the OK model. It is expected that by calibrating the surface interactive parameters with experimental data, the OK model could be applied to various large-scale DSA simulations, e.g., hotspot analysis over a large area, and design/process optimizations with numerous parameters.

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Section: Comparison With Scftsupporting

confidence: 90%

Large-Scale Simulations of Directed Self-Assembly with Simplified Model

Yoshimoto

Taniguchi

2013

J. Photopol. Sci. Technol.

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“…96,97 The material, however, cannot macrophase separate owing to the covalent linkage that binds the polymer blocks together. This self-assembly is referred to as microphase separation, which is perhaps somewhat misleading as the domain sizes are in the order of nanometers, rather than micrometers.…”

Section: Microphase Separationmentioning

confidence: 99%

Block copolymer strategies for solar cell technology

Topham¹,

Parnell²,

Hiorns³

2011

J Polym Sci B Polym Phys

186

169

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A simple overview of the methods used and the expected benefits of block copolymers in organic photovoltaic devices is given in this review. The description of the photovoltaic process makes it clear how the detailed self-assembly properties of block copolymers can be exploited. Organic photovoltaic technology, an inexpensive, clean and renewable energy source, is an extremely promising option for replacing fossil fuels. It is expected to deliver printable devices processed on flexible substrates using high-volume techniques. Such devices, however, currently lack the long-term stability and efficiency to allow organic photovoltaics to surpass current technologies. Block copolymers are envisaged to help overcome these obstacles because of their long term structural stability and their solid-state morphology being of the appropriate dimensions to efficiently perform charge collection and transfer to electrodes.

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“…The scaling exponent α is 1/2 in the weak segregation limit (χNbb ≈ 10.5) and plateaus at 2/3 in the strong segregation limit (χNbb >> 10.5). 11, 12 The small scaling exponent is intrinsically related to the coil-like chain conformations.…”

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confidence: 99%

Effects of Grafting Density on Block Polymer Self-Assembly: From Linear to Bottlebrush

et al. 2017

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Grafting density is an important structural parameter that exerts significant influences over the physical properties of architecturally complex polymers. In this report, the physical consequences of varying the grafting density (z) were studied in the context of block polymer self-assembly. Well-defined block polymers spanning the linear, comb, and bottlebrush regimes (0 ≤ z ≤ 1) were prepared via grafting-through ring-opening-metathesis polymerization. ω-Norbornenyl poly(d,l-lactide) and polystyrene macromonomers were copolymerized with discrete comonomers in different feed ratios, enabling precise control over both the grafting density and molecular weight. Small-angle X-ray scattering experiments demonstrate that these graft block polymers self-assemble into long-range-ordered lamellar structures. For 17 series of block polymers with variable z, the scaling of the lamellar period with the total backbone degree of polymerization (d* ∼ N bb α) was studied. The scaling exponent α monotonically decreases with decreasing z and exhibits an apparent transition at z ≈ 0.2, suggesting significant changes in the chain conformations. Comparison of two block polymer systems, one that is strongly segregated for all z (System I) and one that experiences weak segregation at low z (System II), indicates that the observed trends are primarily caused by the polymer architectures, not segregation effects. A model is proposed in which the characteristic ratio (C ∞), a proxy for the backbone stiffness, scales with N bb as a function of the grafting density: C ∞ ∼ N bb f(z). The scaling behavior disclosed herein provides valuable insights into conformational changes with grafting density, thus introducing opportunities for block polymer and material design.

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Unifying Weak- and Strong-Segregation Block Copolymer Theories

Cited by 1,750 publications

References 69 publications

Large-Scale Simulations of Directed Self-Assembly with Simplified Model

Large-Scale Simulations of Directed Self-Assembly with Simplified Model

Block copolymer strategies for solar cell technology

Effects of Grafting Density on Block Polymer Self-Assembly: From Linear to Bottlebrush

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