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Showing 1 to 20 of 22 for “"selective solvent"”.
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Amphiphilic block copolymers as templates for particle formation and positioning
… employed in the formation of reverse micelles in selective solvents. Polymer micelles were used as nanoreactors, which were loaded by Au or TiO2 precursors and deposited in controlled fashion by a dip-coating technique onto SiO2 substrates to form a hexagonally ordered monomicellar film. Exposure …
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Crystalline Morphologies of Poly(butadiene)-b-Poly(ethylene oxide) Block Copolymers in n-Heptane
… of micellar crystalline morphologies in a selective solvent. The phase diagram of solution morphologies as a function of the molecular composition of the semicrystalline poly(butadiene)-b-poly(ethylene oxide)(PB-b-PEO) block copolymers was investigated. The crystalline morphologies …
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The Physical and Spectroscopic Study of a Series of Poly(3-hexyl thiophene) Homopolymers and Poly(3-hexyl thiophene)-block-Poly(2-hydroxyethyl methacrylate) Diblock Copolymers
In block-selective solvent, the rod-coil block copolymers can form various micellar structures. With block copolymers that contain a conjugated polymer block, the conformation of the conjugated polymer can be reflected by spectral changes in the solution. Therefore, it is of interest to study the …
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Fabrication of Polymersomes using Microfluidic Devices
… using copolymer-stabilized water/organic solvent/water (W/O/W) double emulsion templates. In the former case, the formation of polymersomes occurred at the interface of a flow-focused, copolymer-loaded solvent stream and a selective solvent in a simple microchannel cross junction. …
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Synthese und kolloidale Eigenschaften neuartiger Blockcopolymere mit beta-Dicarbonyl Einheiten = Synthesis and colloidal properties of a novel type of block copolymers bearing beta-dicarbonyl residues
… were observed in cyclohexane as a selective solvent. Depending on the block length ratio, either spherical, elliptical, or cylindrical micelles were formed. The density of the polymer chains at the core/corona interface is considerably higher as compared to any other strongly …
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Synthese und Charakterisierung von Polymerbürsten-Oberflächen mit Gradienten und Strukturierung (Synthesis and characterization of patterned and gradient polymer brush surfaces)
… areas lose the ability to switch. Exposure to selective and non-selective solvent allows visualization or erasing of the written information, respectively. It is demonstrated that developed approaches are promising for design of smart sensors, microfluidics devices, combinatorial study of the …
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Polymeric Nanoparticles for the Modification of Polyurethane Coatings
… with respect to their self-assembly in organic selective solvents. Dynamic light scattering and transmission electron microscopy measurements revealed that spherical micelles were obtained in acetonitrile for all block copolymers, independently of the polymer concentration. Their radii varied …
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Experimental and modeling studies using packed bed reactors: Liquid phase ethylene production by hydrogenation of acetylene
… model at different scales.</p><p>The selective hydrogenation of acetylene in the liquid phase over a commercial 0.5 wt% Pd/Al<sub>2</sub>O<sub>3</sub> catalyst was investigated in a slurry and basket stirred-tank reactor to extract the intrinsic and apparent kinetics respectively, and …
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Determination of Organic Compounds by Atomic Absorption Spectrophotometry (AAS) with Special Reference to Compounds Encountered in Environmental Problems
… spectrophotometric determination of saccharin by selective solvent extraction from aqueous solutions containing an excess of tris-(1,10-phenanthroline)-iron(II) cation into nitrobenzene as an ion-association system, has been thoroughly investigated in order to determine the optimum conditions. …
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Synthesis and Characterization of Novel Polymers for Functional and Stimuli Responsive Silicon Surfaces
… in surface hydrophobicity. In spite of multiple solvent exposures, the copolymer films remained stable on the surface indicating that the observed changes in surface properties were due to selective solvent induced reversible rearrangement of the copolymer blocks. The chemical composition of the …
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Order in Thin Films of Diblock Copolymers by Supramolecular Assembly
… hydrogen bonds. The choice of an additive and a solvent is a key factor which influences the morphologies of the PS-PVP+HABA associates (supramolecular assemblies) in thin films. The reversible association via hydrogen bonds allows the amphiphilic molecules of PDP to phase segregate on the free …
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Study of the dilute solution properties of various homo- and block co-polymers by variable temperature size exclusion chromatography
… of the samples, the solvating power of the solvent used and the operating temperature. Micellization in the hydrocarbon diblock copolymer solutions was found to occur in selective solvent, its extent depending on the solubility parameter difference between the components, molecular weight, …
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Nanoscale Investigation of Adhesion, Friction, and Wear in Chemically Heterogeneous Responsive Polymer Brushes
… and PS+PAA binary brushes on treatment with selective solvents. Maximum switching in adhesion force and friction coefficient was by a factor of 2.7 and 5.4, respectively. Furthermore, switching of friction for mixed brush surface was observed during macroscale friction measurements using …
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Solution-casting of Disulfonated Poly(arylene ether sulfone) Multiblock Copolymer Films for Proton Exchange Membranes
… and kinetics of block copolymers during solvent removal process, which was initially examined in order to provide fundamental quantitative understanding and practical information on the solvent removal process. Our results demonstrated that solvent selectivity and drying temperature as …
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Reactive amphiphilic block copolymers for the preparation of hybrid inorganic/organic materials
… preparation of micellar solutions in toluene as selective solvent. The micelles were characterized by static and dynamic light scattering as well as small angle X-ray scattering. The results of the light scattering experiments showed that copolymers containing a mass fraction of PG block below …
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Self-assembly and selective swelling in Lamellar block copolymer photonic gels
… and P2VP layers parallel to the substrate after solvent vapor annealing. In solvents that are selective to P2VP, the P2VP layers swell while the PS layers remain glassy. The glassy PS layers restrict the lateral expansion of the P2VP layers, and therefore the swelling of P2VP layers occurs only …
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Soft Compartmentalized Polymer Colloids: Janus Particles, Multicompartment Structures, Inorganic-Organic Hybrids and Applications
… the colloidal particles even when exposed to non-selective solvents. Cylindrical and disc-like Janus particles were investigated according to their self-assembly behavior into superstructures. The Janus discs undergo back-to-back stacking in organic solvent. In aqueous solution, a size-dependent …
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Shear-induced alignment in block copolymer solutions
… ABC triblock and their blend in a non-volatile solvent. Before proceeding to the alignment protocols the thermodynamics of the diblock copolymer solutions has been studied by rheological means. The slightly asymmetric diblock copolymer polystyrene-b-poly(t-butyl methacrylate) (ST) as solutions …
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Bottom-up Self-Assembly across Hierarchies: From Triblock Terpolymers to Patchy Particles to Colloidal (Co-)Polymers
… corona patches. Thereby, carefully chosen solvent sequences were of outmost importance. Depending on the volume ratio of the core forming blocks, VA/VB, two species with different geometrical distribution of the patches were identified: for VA/VB > 1, a Janus-like AB distribution, with …
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Study of the phase behavior of poly(n-alkyl methacrylate-b-methyl methacrylate) diblock copolymers and its influence on the wettability of polymer surfaces
… when the films were prepared from a non-selective solvent (THF) onto silicon wafers. Well-recognizable nanostructures with long-range order were mainly found in thin films of diblock copolymers with high molar masses, above 100,000 g/mol, and with a high amount of PPMA. The lateral domain …
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