Neutron reflectivity studies of the surface-induced ordering of diblock copolymer films

Anastasiadis, Spiros H.; Russell, Thomas P.; Satija, Sushil K.; Majkrzak, C. F.

doi:10.1103/physrevlett.62.1852

Cited by 470 publications

(478 citation statements)

References 11 publications

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“…P4VP(PDP) has a lower surface tension that orients the BCP lamellae parallel to the surface. [43][44][45][46] However, when the P4VP(PDP) fraction is higher than a critical value, the preferrential interactions between the supramolecules with the underlying substrate and the lower surface tension of P4VP(PDP) can be overcome. The BCP microdomains can be oriented normal to the surface, which, in turn, provide a framework for the P4VP(PDP) comb blocks to assemble with a preferred macroscopic orientation.…”

Section: Resultsmentioning

confidence: 99%

Hierarchical Assemblies of Block-Copolymer-Based Supramolecules in Thin Films

et al. 2008

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The hierarchical assemblies of supramolecules, which consisted of polystyrene-b-poly(4-vinylpyridine) (PS-b-P4VP) with 3-pentadecylphenol (PDP) hydrogen-bonded to the 4VP, were investigated in thin films after solvent annealing in a chloroform atmosphere. The synergistic coassembly of PS-b-P4VP and PDP was utilized to generate oriented hierarchical structures in thin films. Hierarchical assemblies, including lamellae-within-lamellae and cylinders-within-lamellae, were simultaneously ordered and oriented from a few to several tens of nanometers over macroscopic length scales. The macroscopic orientation of supramolecular assembly depends on the P4VP(PDP) fraction and can be tailored by varying the PDP to P4VP ratio without interfering with the supramolecular morphologies. The lamellar and cylindrical microdomains, with a periodicity of ∼40 nm, could be oriented normal to the surface, while the assembly of comb blocks, P4VP(PDP), with a periodicity of ∼4 nm, were oriented parallel to the surface. Furthermore, using one PS-b-P4VP copolymer, thin films with different hierarchical structures, i.e., lamellae-withinlamellae and cylinders-within-lamellae, were obtained by varying the ratio of PDP to 4VP units. The concepts described in these studies can be potentially applied to other BCP-based supramolecular thin films, thus creating an avenue to functional, hierarchically ordered thin films.

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Section: Resultsmentioning

confidence: 99%

Hierarchical Assemblies of Block-Copolymer-Based Supramolecules in Thin Films

et al. 2008

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“…Thin films have been studied extensively by experiments [5][6][7][8][9][10][11][12][13][14][15] and theory. [16][17][18][19][20][21] In these films the microdomains have a lamellar shape as in a bulk system.…”

Section: A Block Copolymer Thin Filmsmentioning

confidence: 99%

Asymmetric block copolymers confined in a thin film

Huinink

Brokken-Zijp

Dijk

et al. 2000

The Journal of Chemical Physics

186

318

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We have used a dynamic density functional theory ͑DDFT͒ for polymeric systems, to simulate the formation of micro phases in a melt of an asymmetric block copolymer, A n B m ( f A ϭ1/3), both in the bulk and in a thin film. In the DDFT model a polymer is represented as a chain of springs and beads. A spring mimics the stretching behavior of a chain fragment and the spring constant is calculated with the Gaussian chain approximation. Simulations were always started from a homogeneous system. We have mainly investigated the final morphology, adopted by the system. First, we have studied the bulk behavior. The diblock copolymer forms a hexagonal packed array of A-rich cylinders, embedded in a B-rich matrix. Film calculations have been done by confining a polymer melt in a slit. Both the slit width and surface-polymer interactions were varied. With the outcomes a phase diagram for confined films has been constructed. Various phases are predicted: parallel cylinders (C ʈ ), perpendicular cylinders (C Ќ ), parallel lamellae (L ʈ ), and parallel perforated lamellae (CL ʈ ). When the film surfaces are preferentially wet by either the A or the B block, parallel oriented microdomains are preferred. A perpendicular cylindrical phase is stable when neither the A nor B block preferentially wets the surfaces. The predicted phase diagram is in accordance with experimental data in the literature and explains the experimentally observed differences between films of asymmetric block copolymers with only two parameters: the film thickness and the energetic preference of the surface for one of the polymer blocks. We have also observed, that confinement speeds up the process of long range ordering of the microdomains.

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“…This difference in sign gives GANR a high sensitivity for detecting hydrogen in metals (Williams, 1970;Springer, 1974;Majkrzak, Passel & Saxena, 1981). This isotopic substitution of hydrogen by deuterium is largely used in polymer studies to improve the contrast (Anastasiadis, Russel, Satija & Majkrzak, 1989;Bouchaud, Farnoux, Sun, David & Jannink, 1986).…”

Section: Theoretical Considerationsmentioning

confidence: 99%

Improvement of neutron reflectivity of an Ni-Ti multilayer by hydrogenation of titanium layers

Mâcaza¹,

Jiang²,

Samuel³

et al. 1992

J Appl Cryst

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This paper presents the first results confirming the improvement of the neutron reflectivity of Ni-Ti multilayer monochromators by increasing the neutron refractive-index contrast. This operation was performed by hydrogenation of titanium layers during the deposition process in the vacuum chamber. The monochromator, consisting of ten (Ni-TiHx) bilayers and produced by magnetron RF deposition was submitted to heating (to a maximum of 423 K) to study its stability. Variations in both the neutron refractive index of Ni and TiHx layers and the period of the stratified medium were observed. The neutron reflectivity at the first Bragg peak and the refractiveindex contrast are better after this heating treatment relative to the Ni-Ti multilayer with the same period. The very strong hydrogen affinity of titanium facilitates the construction of this bilayer monochromator. The monochromator was studied by grazing-angle neutron reflectometry and X-ray diffraction.

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Neutron reflectivity studies of the surface-induced ordering of diblock copolymer films

Cited by 470 publications

References 11 publications

Hierarchical Assemblies of Block-Copolymer-Based Supramolecules in Thin Films

Hierarchical Assemblies of Block-Copolymer-Based Supramolecules in Thin Films

Asymmetric block copolymers confined in a thin film

Improvement of neutron reflectivity of an Ni-Ti multilayer by hydrogenation of titanium layers

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