Effect of Sinusoidal Surface Roughness and Energy on the Orientation of Cylinder-Forming Block Copolymer Thin Films

We explore the relative stability of three possible orientations of cylinder-forming di-block copolymer on a sinusoidally corrugated substrate. The cylinders can be aligned either parallel to the substrate, with their long axis being oriented along or orthogonal to the corrugation trenches, or perpendicular to the substrate. Using self-consistent field theory, we investigate the influence of substrate roughness and surface preference on the phase transition between the three orientations. When the substrate preference, $u$, towards one of components is small, increasing the substrate roughness induces a phase transition from parallel to perpendicular cylindrical phase. However, when $u$ is large, the parallel orientation is more stable than the perpendicular one. Within this parallel phase, increasing the substrate roughness leads to a transition of cylinder orientation changing from being orthogonal to parallel to the trench long axis. Increasing the substrate preference leads to an opposite transition from parallel to orthogonal to the trenches. Furthermore, we predict that the perpendicular cylinder phase is easier to be obtained when the unidirectional corrugation is along the longer unit vector of the hexagonal packing than when it is along the shorter unit vector. Our results qualitatively agree with previous experiments, and contribute towards applications of the cylinder-forming block copolymer in nanotechnology.Comment: 9 pages, 7 figure

Utilisation du limonène comme synthon agrochimique pour la synthèse et l'extraction de produits naturels

The objective of this study was to transform limonene as an agro-chemical platform for the production of a wide range of added-value compounds for pharmaceutical, cosmetic and food ingredients. This molecule was also evaluated as an alternative solvent for the extraction of several bioactive compounds compared to n-hexane. Limonene was extracted from the essential oils of orange peels through a solvent-free microwave extraction technique. Limonene was successfully transformed into products with industrial interest by catalytic oxidation using three different iron catalysts. The ability of limonene to be used as an alternative solvent was performed using two simulation tools, Hansen solubility parameters (HSPs) and the Conductor-like Screening Model for Real Solvents (COSMO-RS), and via experimentation. The results indicated that limonene could be a promising green solvent and synthon for petroleum substitution in the extraction or synthesis of bioactive compounds.L'objectif de cette étude est de montrer les potentialités du limonène comme une plateforme agrochimique pour la production d'une large gamme de composés à valeur ajoutée pour les industries pharmaceutique, cosmétique et agroalimentaire. Cette molécule a été évaluée en tant que synthon pour la synthèse de molécules bioactives et comme solvant alternatif à l'hexane pour l'extraction de composés bioactifs. Deux outils de simulation solvant--soluté ont été utilisés pour simuler et optimiser les potentialités du limonène : les paramètres de solubilité Hansen (HSP) et le modèle « Conductor-like Screening Model for Real Solvents » (COSMO-RS). Les résultats indiquent que le limonène peut être un solvant vert et un synthon prometteur pour la substitution du pétrole dans l'extraction ou la synthèse de composés bioactifs.This work was supported in part thanks to funding from the fellowship given to Edinson Yara Varón (No. TECSPR14-2-0029) from the People Programme (Marie Curie Actions) of the Seventh Framework Programme of the European Union (FP7/2007-2013) under REA grant agreement no. 600388 (TECNIOspring programme), and from the Agency for Business Competitiveness of the Government of Catalonia, ACCIÓ

High refractive index in low metal content nanoplasmonic surfaces from self-assembled block copolymer thin films

Materials with a high and tunable refractive index are attractive for nanophotonic applications. In this contribution, we propose a straightforward fabrication technique of high-refractive index surfaces based on self-assembled nanostructured block copolymer thin films. The selective and customizable metal incorporation within out-of-plane polymer lamellae produces azimuthally isotropic metallic nanostructures of defined geometries, which were analysed using microscopy and small-angle X-ray scattering techniques. Variable-angle spectroscopic ellipsometry was used to relate the geometrical parameters of the metallic features and the resulting refractive index of the patterned surfaces. In particular, nanostructured gold patterns with a high degree of homogeneity and a gold content as low as 16 vol% reach a refractive index value of more than 3 in the visible domain. Our study thus demonstrates a new route for the preparation of high refractive index surfaces with a low metal content for optical applications

Soft rectangular sub-5 nm tiling patterns by liquid crystalline self-assembly of T-shaped bolapolyphiles

Square and other rectangular nanoscale tiling patterns are of contemporary interest for soft lithography. Though soft square patterns on a ≈40 nm length scale can be achieved with block copolymers, even smaller tiling patterns below 5 nm can be expected for liquid crystalline phases of small molecules. However, these usually form lamellar and hexagonal morphologies and thus the challenge is to specifically design liquid crystal (LC) phases forming square and rectangular structures, being compatible with industrial standards. Here, two distinct types of liquid crystalline rectangular tiling patterns are reported occurring in a series of T‐shaped p‐terphenyl‐based bolapolyphiles. By directed side chain engineering sub‐5 nm sized quadrangular honeycombs with rhombic (c2mm), square (p4mm), and rectangular (p2mm) shapes of the cells are formed by spontaneous self‐assembly. The rectangular honeycomb with p2mm lattice represents a new mode of LC self‐assembly in polygonal honeycombs. In addition, pentagonal and hexagonal tiling motifs can be obtained by molecular fine tuning

Etude de l'auto-organisation de films minces de copolymères diblocs en vue d'applications pour la microélectronique

The aim of this work is to understand how PS-b-PMMA thin films presenting vertically oriented cylindrical PMMA nanodomains self-assemble. These films are used to organize discrete nano-objects with small dimensions (diameter ~ 20 nm) and in high density (~1011/cm ²). It is shown that the vertical cylinder phase is indirectly formed during thermal annealing starting from a homogeneous phase. First, a disordered cylinder phase is created within the film, followed by the nucleation and growth of the vertical cylinder phase . This implies the presence of defects at the grain boundaries so that the obtained films present an hexatic order according to KTHNY theory. For defect sites, the unit cell could adopt an anisotropic configuration due to the stress of the lattice. In this case, in order to minimize the free energy of the system, the PMMA domain deforms commensurately with the unit cell and adopts an elliptical or a lozenge-like cross section, in good agreement with strong segregation considerations. However, these strained configurations reveal to be metastable so that thermal fluctuations could induce a transition from a distorted column to two other circular columns. This phenomenon has been used to explain the motion of dislocations. Finally, we use these films as a mask to realize, by etching plasma, Si/SiGe nano-pillars or MOS capacities with Pt nanocristals.L'objectif de ce travail est de comprendre comment s'auto-organisent les films minces de PS-b-PMMA présentant des nanodomaines cylindriques de PMMA orientés verticalement. Ces films sont ensuite utilisés pour organiser des nano-objets discrets de faibles dimensions (diamètre ~ 20 nm) et en forte densité (~1011/cm²).Il est montré que la phase de cylindres verticaux se forme de façon indirecte pendant le recuit thermique à partir d'une phase homogène. Tout d'abord, il se forme une phase de cylindres désordonnés au sein du film sur laquelle la phase de cylindres verticaux s'établie par un mécanisme de nucléation-croissance, menant à la présence de défauts aux joints de grains. L'élimination des défauts dans le réseau nécéssite une diffusion de ces derniers. Après avoir montré expérimentalement et théoriquement que les sites heptacoordinés adoptent une morphologie distordue en raison de la contrainte du réseau, nous proposons un mécanisme de diffusion des dislocations basé sur la division des nanodomaines distordus. Nous montrons que les films réalisés possédent un ordre hexatique selon la théorie KTHNY. Finalement, nous utilisons ces films en tant que masque pour réaliser, par gravure plasma, des nano-piliers en Si/SiGe ou bien des capacités MOS à nanocristaux de P

Highly Ordered Nanoring Arrays Formed by Templated Si-​Containing Triblock Terpolymer Thin Films

In this work, the directed selfassembly of Si-​contg. triblock terpolymer chains ordered into nanoscale ring arrays has been reported. To produce long-​range ordered ring patterns, a solvent vapor annealing (SVA) methodol. was used to promote the mobility of the poly(1,​1-​dimethylsilacyclobutane)​block-​polystyrene-​block-​poly(Me methacrylate) (PDMSB-​b-​PS-​b-​PMMA or DSM) chains deposited on topog. patterned silica substrates. By using this strategy, highly ordered core​/shell cylinders with a domain orientation change induced by the film thickness were demonstrated. An effective control of the domain orientation was achieved by using a blending methodol., which revealed an efficient route to fabricate templated DSM thin films with core​/shell cylinders having a highly desired out-​of-​plane orientation both on mesas and in trenches

Etude de l auto-organisation de films minces de copolymères diblocs en vue d applications pour la microélectronique

L objectif de ce travail est de comprendre comment s auto-organisent les films minces de PS-b-PMMA présentant des nanodomaines cylindriques de PMMA orientés verticalement. Ces films sont ensuite utilisés pour organiser des nano-objets discrets de faibles dimensions (diamètre ~ 20 nm) et en forte densité (~1011/cm ). Il est montré que la phase de cylindres verticaux se forme de façon indirecte pendant le recuit thermique à partir d une phase homogène. Tout d abord, il se forme une phase de cylindres désordonnés au sein du film sur laquelle la phase de cylindres verticaux s établie par un mécanisme de nucléation-croissance, menant à la présence de défauts aux joints de grains. L élimination des défauts dans le réseau nécéssite une diffusion de ces derniers. Après avoir montré expérimentalement et théoriquement que les sites heptacoordinés adoptent une morphologie distordue en raison de la contrainte du réseau, nous proposons un mécanisme de diffusion des dislocations basé sur la division des nanodomaines distordus. Nous montrons que les films réalisés possédent un ordre hexatique selon la théorie KTHNY. Finalement, nous utilisons ces films en tant que masque pour réaliser, par gravure plasma, des nano-piliers en Si/SiGe ou bien des capacités MOS à nanocristaux de PtThe aim of this work is to understand how PS-b-PMMA thin films presenting vertically oriented cylindrical PMMA nanodomains self-assemble. These films are used to organize discrete nano-objects with small dimensions (diameter ~ 20 nm) and in high density (~1011/cm ). It is shown that the vertical cylinder phase is indirectly formed during thermal annealing starting from a homogeneous phase. First, a disordered cylinder phase is created within the film, followed by the nucleation and growth of the vertical cylinder phase . This implies the presence of defects at the grain boundaries so that the obtained films present an hexatic order according to KTHNY theory. For defect sites, the unit cell could adopt an anisotropic configuration due to the stress of the lattice. In this case, in order to minimize the free energy of the system, the PMMA domain deforms commensurately with the unit cell and adopts an elliptical or a lozenge-like cross section, in good agreement with strong segregation considerations. However, these strained configurations reveal to be metastable so that thermal fluctuations could induce a transition from a distorted column to two other circular columns. This phenomenon has been used to explain the motion of dislocations. Finally, we use these films as a mask to realize, by etching plasma, Si/SiGe nano-pillars or MOS capacities with Pt nanocristals.GRENOBLE1-BU Sciences (384212103) / SudocSudocFranceF

Laterally Ordered Sub-10 nm Features Obtained From Directed Self-Assembly of Si-Containing Block Copolymer Thin Films

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