Orientation and relaxation behaviors of lamellar microdomains of poly(methyl methacrylate)-b-poly(n-butyl acrylate) thin films as revealed by grazing-incidence small-angle X-ray scattering

Saito, Ikue; Shimada, Daiki; Aikawa, Mayu; Miyazaki, Tsukasa; Shimokita, Keisuke; Takagi, Hideaki; Yamamoto, Katsuhiro

doi:10.1038/pj.2016.2

Cited by 12 publications

(4 citation statements)

References 77 publications

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“…GISAXS data were collected using a 10 s integration time and a grazing-incidence angle of 0.10°. This angle is above the critical angle (∼0.096°), and the calculated penetration depth was ∼10 5 nm, indicating that the entire film is sampled in all GISAXS measurements. This assessment is supported by L measurements by GISAXS for the 114 nm thick 22 kg/mol HP blend film at the same position while using different incidence angles above the critical angle.…”

Section: Experimental Methodsmentioning

confidence: 89%

Film Thickness and Composition Effects in Symmetric Ternary Block Copolymer/Homopolymer Blend Films: Domain Spacing and Orientation

et al. 2021

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We report thickness and homopolymer molar mass dependencies in thin film blends of a compositionally symmetric 75 kg/mol lamellar polystyrene-block-poly(methyl methacrylate) diblock copolymer (PS-b-PMMA) with near-equal volume fractions of PS and PMMA homopolymers on "neutral" surfaces that promote a vertical domain orientation. PS and PMMA homopolymers with equal molar masses of 1, 3, and 22 kg/mol are blended in a 1:1 mass ratio. To efficiently explore this parameter space, we prepared combinatorial samples with gradient homopolymer concentrations using electrospray deposition (ESD) and gradient film thicknesses using flow coating; these samples were subsequently characterized by grazing-incidence small-angle X-ray scattering and scanning electron microscopy, respectively. Our results demonstrate that the added homopolymers increase or reduce domain spacings with respect to the neat (unblended) block copolymer depending on their molar masses, in line with previous reports; a simple heuristic to estimate the domain scaling in ternary blends based on the homopolymer molar mass agrees well with data for the thinnest blend films studied here. More surprisingly, we observe that the measured domain spacing in blends also depends on film thickness, with thicker films exhibiting larger domain spacings than thinner films at the same homopolymer concentration. Furthermore, thickness gradients at fixed homopolymer concentrations reveal a change in lamellae orientation from vertical to horizontal as film thickness is increased beyond the nominal lamellar domain spacing. Coarse-grained molecular dynamics simulations indicate that this change in orientation is induced by homopolymer segregation to film surfaces. Tying these effects together, we hypothesize that the observed dependence of domain spacing on film thickness is a consequence of changes in the vertical homopolymer composition profile in thicker films during lamellae reorientation and the conformational asymmetry between PMMA and PS segments.

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Section: Experimental Methodsmentioning

confidence: 89%

Film Thickness and Composition Effects in Symmetric Ternary Block Copolymer/Homopolymer Blend Films: Domain Spacing and Orientation

et al. 2021

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“…Various SVA setups have been designed to precisely control the processing parameters, e.g., the annealing temperature, making the method a reliable way to process block copolymer thin films for applications. [ 19–27 ] In situ experiments [ 28–32 ] and simulation studies [ 33–37 ] have been performed to elucidate the structural changes during SVA and thus to improve the understanding of the annealing process, resulting in more powerful processing protocols.…”

Section: Figurementioning

confidence: 99%

Solvent Vapor Annealing of a Diblock Copolymer Thin Film with a Nonselective and a Selective Solvent: Importance of Pathway for the Morphological Changes

Jung

Berezkin

Tejsner

et al. 2020

Macromol. Rapid Commun.

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Diblock copolymer thin films of polystyrene‐block‐poly(dimethyl siloxane) (PS‐b‐PDMS) featuring PDMS cylinders in a PS matrix are investigated during solvent vapor annealing with mixtures of n‐heptane (which is strongly selective for PDMS) and toluene (which is close to nonselective for both blocks). Swelling in the vapor of one of the pure solvents and exchanging it stepwise by the vapor of the other solvent is compared to swelling in a given binary solvent vapor mixture for a prolonged time. The resulting structural changes, such as ordering of the cylinders on a hexagonal lattice and their transition into lamellae, are followed using in situ, real‐time grazing‐incidence small‐angle X‐ray scattering (GISAXS). In three runs, the sequence of solvent vapor swelling and vapor exchange is varied. Compiling the resulting morphologies in a diagram of states in dependence on the solvent content in the film and in the minority nanodomains allows insight into the role of the glass transition of the PS matrix for the ordering processes and their time scales. Based on these findings, a protocol is suggested to efficiently obtain an order‐to‐order transition from the cylindrical morphology with random domain orientation to the oriented lamellar state.

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“…With nGISAXS, the X-ray beam size is decreased further (as small as 300 nm diameter) to probe the through-film profile across localized areas [121]. To improve contrast between domains, GI-RSoXS incorporates low-energy, or "soft" X-rays to measure depth-resolved structure and composition profiles [168,169]. Additionally, as an alternative to traditional GISAXS, CDSAXS examines buried interfaces by collecting 2D profiles from multiple transmission scattering angles to construct a 3D reciprocal-space map of periodic nanostructures [170][171][172].…”

Section: Transmission X-ray Scattering For In-plane Analysis Of Thin mentioning

confidence: 99%

Block copolymer thin films: Characterizing nanostructure evolution with in situ X-ray and neutron scattering

Shelton

Epps

2016

Polymer

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Block copolymer (BCP) thin films have attracted significant attention as lithographic templates, separation membranes, and organic photovoltaic active layers for emerging nanotechnologies due to their ability to self-assembly into nanoscale features. To direct the selfassembly of BCP thin film nanostructures into ordered arrays, a suite of annealing techniques have been developed (e.g. thermal annealing, solvent vapor annealing, magnetic/electrical field alignment), each with its own set of controllable parameters and mechanisms for nanostructure reorganization. In this Review, we discuss the importance of in situ X-ray and neutron scattering for the study of BCP thin films subjected to different annealing protocols. These scattering approaches have become vital for understanding the complex nanostructure reorganization processes inherent in thin film fabrication and for establishing more consistent control over the morphology, ordering, and orientation. A major advantage of in situ X-ray and neutron scattering characterization is the ability to link the thermodynamic and kinetic pathways of nanostructure evolution over macroscopic (several cm 2) areas during annealing or processing. This feature has made in situ X-ray and neutron scattering ideal for refining annealing techniques, fostering robust assembly protocols, and developing the next-generation of directed assemblies. As the toolbox of viable processing methods continues to grow, we highlight potential opportunities to enhance current X-ray and neutron scattering capabilities through the improvement of scattering facilities, techniques, sample chambers, scattering/annealing protocols, and model development to establish universal control over BCP thin film selfassembly.

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Orientation and relaxation behaviors of lamellar microdomains of poly(methyl methacrylate)-b-poly(n-butyl acrylate) thin films as revealed by grazing-incidence small-angle X-ray scattering

Cited by 12 publications

References 77 publications

Film Thickness and Composition Effects in Symmetric Ternary Block Copolymer/Homopolymer Blend Films: Domain Spacing and Orientation

Film Thickness and Composition Effects in Symmetric Ternary Block Copolymer/Homopolymer Blend Films: Domain Spacing and Orientation

Solvent Vapor Annealing of a Diblock Copolymer Thin Film with a Nonselective and a Selective Solvent: Importance of Pathway for the Morphological Changes

Block copolymer thin films: Characterizing nanostructure evolution with in situ X-ray and neutron scattering

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