Lamellar Diblock Copolymer Thin Films during Solvent Vapor Annealing Studied by GISAXS: Different Behavior of Parallel and Perpendicular Lamellae

Zhang, Jianqi; Posselt, Dorthe; Smilgies, Detlef‐M.; Perlich, Jan; Kyriakos, Konstantinos; Jaksch, Sebastian; Papadakis, Christine M.

doi:10.1021/ma500633b

Cited by 57 publications

(111 citation statements)

References 44 publications

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“…At room temperature (RT), vN ffi 25 [55], the sample is thus in the intermediate segregation regime [56]. The bulk structure of the PS-b-PB diblock copolymer is lamellar with a lamellar thickness D bulk lam ¼ 220 AE 4 Å, and the lamellae are almost symmetric, as observed using transmission small-angle X-ray scattering [54]. The glass transition temperatures of the PS and the PB domains of a similar PS-b-PB diblock copolymer are 76°C and À89°C, respectively [55].…”

Section: Methodsmentioning

confidence: 95%

Toward an equilibrium structure in lamellar diblock copolymer thin films using solvent vapor annealing – An in-situ time-resolved GISAXS study

Sepe

Zhang

Perlich

et al. 2016

European Polymer Journal

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a b s t r a c tSolvent vapor annealing (SVA) is frequently used to improve the ordering in diblock copolymer thin films. An important question is which SVA protocol should be chosen to ensure thermodynamic equilibrium. Here, we investigate two thin films from a low molar-mass, lamellae-forming polystyrene-block-polybutadiene (PS-b-PB) diblock copolymer (28.0 kg/mol). The films are prepared by spin-coating Si wafers from toluene solutions and have film thicknesses of 215 nm and 332 nm. The as-prepared films have mainly the parallel lamellar orientation with a lamellar thickness D lam,par significantly lower than in the bulk. SVA cycles were carried out with cyclohexane, and the structural changes were followed in-situ using time-resolved grazing-incidence small-angle X-ray scattering (GISAXS). Before and after SVA, D lam,par is significantly lower than in the bulk, i.e. the equilibrium value of D lam,par in thin film geometry is different from the bulk value. Whereas the behavior of D lam,par is different for the two films in the early stages of the first swelling, it is very similar in the late stages of swelling and during drying. During the first drying, the lamellae deswell, initially slowly and later, when PS becomes glassy again, affinely. During the second SVA cycle on the thin film, the scaling behavior of the lamellar thickness is identical to the one during the first drying and to the drying behavior of the thicker film. We conclude that one cycle of solvent vapor treatment with a degree of swelling of ca. 1.5 is sufficient to bring the PS-b-PB thin films studied into equilibrium and to create a nearly defect-free lamellar structure.

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Section: Methodsmentioning

confidence: 95%

Toward an equilibrium structure in lamellar diblock copolymer thin films using solvent vapor annealing – An in-situ time-resolved GISAXS study

Sepe

Zhang

Perlich

et al. 2016

European Polymer Journal

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“…In this way, the lamellar orientation of poly(styreneb-butadiene) (PS-b-PB) copolymer has been found to be strongly dependent on solvent annealing process [15]. The reorientation of lamellae occurred during solvent vapor annealing with ethyl acetate.…”

Section: Lamellar Morphologymentioning

confidence: 92%

“…It has been commonly found for many diblock copolymer thin films, both without any further treatment or after thermal or solvent vapor annealing. Both thermal and solvent annealing methods have been used to bring the samples into their equilibrium states and to reduce the number of defects [15]. Lamellar morphology can be used to create line and space patterns on substrates by controlling their orientation.…”

Section: Lamellar Morphologymentioning

confidence: 99%

“…Lamellar morphology can be used to create line and space patterns on substrates by controlling their orientation. Lamellar orientation depends on several parameters and/or factors such as the substrate used for film preparation [16,17], thermal or solvent vapor annealing treatments [15,17,18], chain length or molar mass [16,17,19], pressure application during annealing [20] or the use of graphoepitaxial techniques for film preparation [21][22][23]. Thus, different orientations have been obtained for different block copolymers by controlling those parameters.…”

Section: Lamellar Morphologymentioning

confidence: 99%

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Nanostructured Morphologies by Self-Assembly of Diblock Copolymers: A Review

Kortaberría¹

2017

Molecular Self-Assembly in Nanoscience and Nanotechnology

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Due to the thermodynamic incompatibility between blocks, diblock copolymers can selfassemble in a wide variety of nanostructures, covalent linkage among blocks preventing the phase separation at macroscopic scale. Those nanostructures depend on copolymer composition (f), Flory-Huggins interaction parameter among both blocks (χ), and polymerization degree of the copolymer (N). Thin films of block copolymers can show different equilibrium morphologies such as spheres, cylinders, gyroids, and lamellas. Besides mentioned parameters, film preparation process (substrate, annealing process if any) and used solvent will determine self-assembled morphology. In the present review, the most important morphologies or microstructures obtained for different diblock copolymer films are presented, as well as the most important phase transitions among them. Different microstructures and the way in which they can be obtained become of great importance, as they could be used as templates for nanoparticle deposition, nanolithography, or nanopatterned materials with several potential applications in different fields such as nanoelectronics or nanomedicine.

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“…The method of choice for BCP films was always dip-coating under controlled conditions. The present work aimed at investigating the effect of different annealing procedures (temperature and solvent vapour annealing, as reported in Sepe et al (2014) and Zhang et al (2014)) on the improvement of the morphology. Incorporation of nanoparticles into the polymer matrix is probably the most important step of nanoparticle array preparation.…”

Section: Introductionmentioning

confidence: 99%

Thin-film morphologies of block copolymers with nanoparticles

et al. 2015

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Diblock copolymers (BCP) show phase separation on mesoscopic length scales and form ordered morphologies in both bulk and thin films, the latter resulting in nanostructured surfaces. Morphologies in thin films are strongly influenced by film parameters, the ratio of film thickness and bulk domain spacing. Laterally structured polymer surfaces may serve as templates for controlled assembly of nanoparticles. We investigated BCP of poly(n-pentyl methacrylate) and poly(methyl methacrylate) which show bulk morphologies of stacked lamellae or hexagonally packed cylinders. Thin films were investigated by atomic force microscopy and grazing-incidence small-angle X-ray scattering. For film thicknesses f well below d bulk , standing cylinder morphologies were observed in appropriate molar ratios, while film thicknesses around and larger than d bulk resulted in cylinders arranged parallel to surface. To alter and/or improve the morphology also in presence of different nanoparticles (NP: silica, gold), solvent vapour annealing (SVA) was applied. The BCP morphology usually remains unchanged but periodicities change depending on type and amount of incorporated NPs. It was found that silica clusters enlarge lateral distances of cylinders, whereas Au NPs reduce it. The effect of SVA is weak. The quality of morphology is slightly improved by SVA and lateral distances remain constant or are slightly reduced.

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Lamellar Diblock Copolymer Thin Films during Solvent Vapor Annealing Studied by GISAXS: Different Behavior of Parallel and Perpendicular Lamellae

Cited by 57 publications

References 44 publications

Toward an equilibrium structure in lamellar diblock copolymer thin films using solvent vapor annealing – An in-situ time-resolved GISAXS study

Toward an equilibrium structure in lamellar diblock copolymer thin films using solvent vapor annealing – An in-situ time-resolved GISAXS study

Nanostructured Morphologies by Self-Assembly of Diblock Copolymers: A Review

Thin-film morphologies of block copolymers with nanoparticles

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