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Showing 1 to 20 of 26 for “"colloidal crystal"”.
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Theory and fabrication of colloidal-crystal Bragg filters
… based on material parameters, is developed for colloidal-crystal Bragg filters. The coupling constant, for coupled-wave equations, is derived to produce filter spectra. The spectra are modified by convolving with a Gaussian function to represent crystal defects. Scattering losses are calculated …
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Synthesis and Characterization of Functional Mesostructures Using Colloidal Crystal Templating
… 3-D periodic mesostructures were synthesized via colloidal crystal templating, and their chemical, physical, and optical properties were characterized. By forming colloidal crystals through self-organization, infiltrating the interstitial space with functional materials, and removing the templates …
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Fabrication of Three-Dimensionally Ordered Nanostructured Materials Through Colloidal Crystal Templating
The void spaces in colloidal crystals (opals, three-dimensional (3D) close-packed arrays of silica nanospheres) and their replicas are used as templates in the fabrication of new nanostructured materials. 3D ordered nanomeshes and nanosphere arrays are readily obtained by chemical and/or …
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Unique templating of and applications enabled through mesoporous colloids
… enabled by utilizing mesoporous colloids, colloidal crystals, and films. Silica colloidal crystals, having colloids of less than 300 nm, were fabricated and used as a template for silicon deposition. Brillouin Light Scattering (BLS) experiments conducted on a silicon templated silica …
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Evaporation-Driven Assembly as a Route to Photonic Materials
… diffraction properties of photonic crystals have inspired their proposed use in applications ranging from chemosensors, to solar power applications, to optical computing devices. The range of proposed applications for photonic crystals demands a range of techniques for fabricating …
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Characterization and fabrication of nanoporous materials by template directed sol-gel methods
… using template assisted sol-gel routes. Both colloidal crystals and surfactant self assemblies were employed as templates.<br/>Initial studies focussed on the fabrication of macroporous titano/alumino and tinsilicate materials by dip infiltrating colloidal crystal templates with sol-gel …
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Controlling Microbial Colonization and Biofilm Formation Using Topographical Cues
… 3D biofilms rarely occur on a solid with a colloidal crystal coating of 1550 nm spheres. On 450 nm colloidal crystals, the bacterial growth was intermediate between the flat and 1550 nm spheres. The initial preference for P. aeruginosa to adhere to confined spaces is maintained on the second …
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Fabrication of three-dimensional nanostructures for thermal study
… are discussed. Using self-assembly of colloidal silica particles as a template, various dielectrics of interest were filled to create nanostructured dielectric materials. First, sub-100 nanometer silica nanoparticles were synthesized and used to assemble a colloidal crystal template, …
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Fundamental studies towards the fabrication of electroactive monolithic stationary phases in microfluidic channels
… electrochemical cell into a microfluidic chip, colloidal crystallization in microfluidic channels and PANI growth through a colloidal crystal template. Polyaniline was selected as the electroactive material for the fabrication of the monolithic stationary phase as its use for EMLC had already …
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Two -Photon Polymerization of Defects in Photonic Crystals
… a complete PBG, it is necessary to convert colloidal photonic crystals to higher refractive index structures that exhibit complete PBGs. To this end, self-assembled photonic crystals with embedded TPP features were replicated in silicon. The TPP features and colloidal crystal served as a …
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Direct-write assembly of colloidal materials
Colloidal assembly, which is the spontaneous organization of nano- and micro- sized particles, is an attractive means to create materials with properties that can be engineered via hierarchy of particle composition, size, ordering, and macroscopic form. However, while there are well-established …
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Inverse opal hydrogel scaffolds as lymphoid microenvironments for the study of immune cell migration and immunotherapy
… and immunotherapy. By applying the method of colloidal crystal templating to materials and length scales appropriate for soft tissues, PEG hydrogels with arrays of ordered, interconnected pores were prepared. These combined the attractive properties of hydrogels, including biochemical …
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Materials with engineered mesoporosity for programmed mass transport
… 4.1 nm through swelling of the lyotropic liquid crystal template. The incorporation of a swelling agent is shown to linearly vary the hexagonal lyotropic liquid crystalline phase, which templates the mesopores, while allowing the high fidelity synthesis of mesoporous hollow spheres. …
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Surface Modification and Self-Assembly of Gold Nanostructures
… of gold nanoparticles with a liquid crystalline ligand that structurally resembles liquid crystal 5CB. Functionalized gold nanoparticles show increased solubility in liquid crystal compared to their alkanethiolated analogues. Surface modification technique was also applied to detoxify …
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Use of Spatially Non-Uniform Electric Fields for Contact-Free Assembly of Three-Dimensional Structures from Colloidal Particles
… to the use of non-uniform electric field driven colloidal assembly are described. The first relates to experimental work using dielectrophoretic and electrohydrodynamic forces (electroosmosis) to shape three-dimensional colloidal structures. Formation and stabilization of close-packed …
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Polymer hydrogel nanoparticles and their networks
… gels, while self-assembly provides them with crystal structures that diffract light, resulting in colors. By using N-isopropylacrylamide copolymer hydrogel nanoparticles, we have synthesized nanoparticle networks that display a striking iridescence like precious opal but are soft and flexible …
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Membrane Surface Engineering for Biochemical Applications
… throughput and easy to scale up. Unique inverse colloidal crystal (ICC) membranes were developed with highly periodic structures, high porosity, and fully interconnected pores. ICC membranes offer a very high binding capacity for IgG4. On the other hand, salt responsive membranes were developed …
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Attractive electrostatic self-assembly of ordered and disordered heterogeneous colloids
Ionic colloidal crystals are here defined as multicomponent ordered colloidal structures stabilized by attractive electrostatic interactions. These crystals are colloidal analogues to ionic materials including zincblende, rocksalt, cesium chloride, and fluorite. A thermodynamic study revealed that …
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Synthesis and study of crystalline hydrogels, guided by a phase diagram.
… (PNIPAM-co-allylamine) can self-assemble into crystals with a lattice spacing on the order of the wavelength of visible light. By initiating the crystallization process near the colloidal crystal melting temperature, while subsequently bonding the PNIPAM-co-allylamine particles below the glass …
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Improving energy and power densities of three-dimensional next generation secondary battery electrodes
… electrode was fabricated using self-assembly, colloidal crystal templating and electrodeposition methods. A good rate performance was obtained as well as a reduced voltage hysteresis was observed for the first time on the Fe2O3 system. The underlying mechanism behind the reduced voltage …
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