Thin films of block copolymer supramolecular assemblies: Microphase separation and nanofabrication

Böhme, Marcus; Kuila, Biplab Kumar; Schlörb, H.; Nandan, Bhanu; Stamm, Manfred

doi:10.1002/pssb.201046159

Cited by 20 publications

(19 citation statements)

References 78 publications

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“…This would be clearly more difficult or impossible to accomplish with related ditopic hydrogen-bond donors by relying, for example, on highly polar moieties such as carboxylic groups, 40 which are not soluble in non-polar solvents.…”

Section: Discussionmentioning

confidence: 99%

Hierarchical Self-Assembly of Halogen-Bonded Block Copolymer Complexes into Upright Cylindrical Domains

Milani

Houbenov

Fernández-Palacio

et al. 2017

Chem

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SummarySelf-assembly of block copolymers into well-defined, ordered arrangements of chemically distinct domains is a reliable strategy for preparing tailored nanostructures. Microphase separation results from the system, minimizing repulsive interactions between dissimilar blocks and maximizing attractive interactions between similar blocks. Supramolecular methods have also achieved this separation by introducing small-molecule additives binding specifically to one block by noncovalent interactions. Here, we use halogen bonding as a supramolecular tool that directs the hierarchical self-assembly of low-molecular-weight perfluorinated molecules and diblock copolymers. Microphase separation results in a lamellar-within-cylindrical arrangement and promotes upright cylindrical alignment in films upon rapid casting and without further annealing. Such cylindrical domains with internal lamellar self-assemblies can be cleaved by solvent treatment of bulk films, resulting in separated and segmented cylindrical micelles stabilized by halogen-bond-based supramolecular crosslinks. These features, alongside the reversible nature of halogen bonding, provide a robust modular approach for nanofabrication.

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Section: Discussionmentioning

confidence: 99%

Hierarchical Self-Assembly of Halogen-Bonded Block Copolymer Complexes into Upright Cylindrical Domains

Milani

Houbenov

Fernández-Palacio

et al. 2017

Chem

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“…It may be added here that the vertical cylinders may have formed by a mechanism involving the vertical coalescence of spheres due to out-of-plane film shrinkage during solvent evaporation, as proposed by Stamm and co-workers for PS− P4VP films (10 wt % P4VP) containing nominally equimolar 2-(4′-hydroxyphenylazo)benzoic acid (HABA) that were vapor annealed by p-dioxane. 15,16,54 For NCOOH-containing p-dioxane solutions, the surface morphology was observed to evolve with increasing dip-coating rate from dots, to mixed dots and short stripes, to long stripes, to another mixed dot-and-stripe region. This is consistent with an evolution from a spherical morphology, to a transition region of mixed spheres and horizontal cylinders, to a pure cylindrical morphology where the cylinders are first oriented horizontally (7−15 mm/min where the films are near the thickness minimum) and then both horizontally and vertically.…”

Section: Macromoleculesmentioning

confidence: 93%

Solvent Influence on Thickness, Composition, and Morphology Variation with Dip-Coating Rate in Supramolecular PS-b-P4VP Thin Films

et al. 2015

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Recent literature has shown that the thickness of dip-coated films has a V-shaped dependence on dip-coating rate when very slow rates are included. For supramolecular block copolymer films, small molecule (SM) uptake and film morphology are also rate-dependent, as shown previously for a poly(styrene-b-4-vinylpyridine) (PS−P4VP) block copolymer in THF solutions containing naphthol (NOH) and naphthoic acid (NCOOH). Here, these investigations are extended to p-dioxane, toluene, and CHCl 3 solutions. The V-shaped thickness dependence is validated for each solvent, but with the V minimum displaced to lower dip-coating rates and thicknesses for the solvents with lower vapor pressures (p-dioxane, toluene), thereby decreasing the dip-coating rate range of the "capillarity regime" (slow side of the V) and consequently extending that of the "draining regime" (fast side of the V). The SM/VP uptake ratio varies with the nature of the solvent, particularly in the capillarity regime, where it is higher for solvents that are weak SM-VP hydrogen-bond competitors (toluene, CHCl 3 ). The draining regime generally shows greater SM uptake than the capillarity regime, in some cases reaching the solution ratio, with higher uptake observed for the SM with greater hydrogen-bond strength (NCOOH > NOH). The variation in film morphology with solvent and dip-coating rate (spherical for toluene; spherical and cylindrical for p-dioxane; spherical, cylindrical, and lamellar for THF; and lamellar only for CHCl 3 ; for a block copolymer whose equilibrium morphology in the bulk is near the cylindrical/lamellar phase boundary) depends on the initial solution state (whether micellar or not and hardness of micelles) and the SM uptake ratio. These factors, along with solvent evaporation rate and film thickness, influence the kinetics of morphology development in the drying films, the point at which the kinetics are frozen in, the effective block ratio, and the orientation of the morphological structures.

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“…The most promising candidates for such a template are diblock copolymers. The significantly reduced pore size complicates the electrodeposition process, but filling these templates with magnetic material is already reported [28,59,60].…”

Section: Temperature Dependence Of Magnetic Propertiesmentioning

confidence: 97%

Magnetic nanowires by electrodeposition within templates

Schlörb

Haehnel

Khatri

et al. 2010

Physica Status Solidi (b)

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146

111

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Magnetic nanowire arrays allow studying magnetism at the nanoscale and have broad application areas. Here we review our recent experiments on tailoring the structure and microstructure of electrochemically grown elemental (Fe, Ni, Co) and alloy (Co-Pt) magnetic nanowires. The comparison of these different materials allows identifying the role of shape, magnetocrystalline and magnetoelastic anisotropies as well as magnetostatic interactions.

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Thin films of block copolymer supramolecular assemblies: Microphase separation and nanofabrication

Cited by 20 publications

References 78 publications

Hierarchical Self-Assembly of Halogen-Bonded Block Copolymer Complexes into Upright Cylindrical Domains

Hierarchical Self-Assembly of Halogen-Bonded Block Copolymer Complexes into Upright Cylindrical Domains

Solvent Influence on Thickness, Composition, and Morphology Variation with Dip-Coating Rate in Supramolecular PS-b-P4VP Thin Films

Magnetic nanowires by electrodeposition within templates

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