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Transparent Materials (transparent + material)

Distribution by Scientific Domains
Polymers and Materials Science45%
Physics and Astronomy36%

Selected Abstracts

Optical Power Limiters Based on Colorless Di-, Oligo-, and Polymetallaynes: Highly Transparent Materials for Eye Protection Devices,

ADVANCED FUNCTIONAL MATERIALS, Issue 6 2007
G.-J. Zhou
Abstract The synthesis, characterization, and photophysics of a series of solution-processable and tractable di-, oligo-, and polymetallaynes of some group 10,12 transition metals are presented. Most of these materials are colorless with very good optical transparencies in the visible spectral region and exhibit excellent optical power limiting (OPL) for nanosecond laser pulse. Their OPL responses outweigh those of the state-of-the-art reverse saturable absorption dyes such as C60, metalloporphyrins, and metallophthalocyanines that are all associated with very poor optical transparencies. On the basis of the results from photophysical studies and theoretical calculations, both the absorption of triplet and intramolecular charge-transfer states can contribute to the enhancement of the OPL properties for these materials. Electronic influence of the type, spatial arrangement, and geometry of metal groups on the optical transparency/nonlinearity optimization is evaluated and discussed in detail. The positive contribution of transition metal ions to the OPL of these compounds generally follows the order: Pt,>,Au,>,Hg,>,Pd. The optical-limiting thresholds for these polymetallaynes can be as low as 0.07,J,cm,2 at 92,% linear transmittance and these highly transparent materials manifest very impressive figure of merit ,ex/,o values (up to 22.48), which are remarkably higher than those of the benchmark C60 and metal phthalocyanine complexes. The present work demonstrates an attractive approach to developing materials offering superior OPL/optical transparency trade-offs and these metallopolyynes are thus very promising candidates for use in practical OPL devices for the protection of human eyes and other delicate optical sensors. [source]

Nanostructured thermosets from self-assembled amphiphilic block copolymer/epoxy resin mixtures: effect of copolymer content on nanostructures

POLYMER INTERNATIONAL, Issue 4 2010
Miren Blanco
Abstract Nanostructure formation in thermosets can allow the design of materials with interesting properties. The aim of this work was to obtain a nanostructured epoxy system by self-assembly of an amphiphilic diblock copolymer in an unreacted epoxy/amine mixture followed by curing of the matrix. The copolymer employed was polystyrene- block -poly(methyl methacrylate) (PS- b -PMMA). The thermoset system, formed by a diglycidyl ether of bisphenol A-type epoxy resin and diaminodiphenylmethane hardener, was chosen to ensure the miscibility of most of the PMMA block until matrix gelation. Transparent materials with microphase-separated domains were obtained for copolymer contents lower than 40 wt%. In systems containing 20 and 30 wt% block copolymer, the PS block formed spherical micelles or worm-like structures before curing, which were stabilized through curing by the more compatible PMMA block phase. Nanostructured thermoset systems were successfully synthesized for self-assembled amphiphilic block copolymer,epoxy/amine mixtures for copolymer contents lower than 40 wt%. Copyright © 2009 Society of Chemical Industry [source]

Porous Polymer Coatings: a Versatile Approach to Superhydrophobic Surfaces

ADVANCED FUNCTIONAL MATERIALS, Issue 12 2009
Pavel A. Levkin
Abstract Here, a facile and inexpensive approach to superhydrophobic polymer coatings is presented. The method involves the in situ polymerization of common monomers in the presence of a porogenic solvent to afford superhydrophobic surfaces with the desired combination of micro- and nanoscale roughness. The method is applicable to a variety of substrates and is not limited to small areas or flat surfaces. The polymerized material can be ground into a superhydrophobic powder, which, once applied to a surface, renders it superhydrophobic. The morphology of the porous polymer structure can be efficiently controlled by composition of the polymerization mixture, while surface chemistry can be adjusted by photografting. Morphology control is used to reduce the globule size of the porous architecture from micro down to nanoscale thereby affording a transparent material. The influence of both surface chemistry as well as the length scale of surface roughness on the superhydrophobicity is discussed. [source]

Symmetric Versus Unsymmetric Platinum(II) Bis(aryleneethynylene)s with Distinct Electronic Structures for Optical Power Limiting/Optical Transparency Trade-off Optimization

ADVANCED FUNCTIONAL MATERIALS, Issue 4 2009
Guijiang Zhou
Abstract A new series of symmetric and unsymmetric Pt(II) bis(acetylide) complexes of the type DC,CPt(PBu3)2C,CD (DPtD), AC,CPt(PBu3)2C,CA (APtA) and DC,CPt(PBu3)2C,CA (DPtA) (D, donor groups; A, acceptor groups) are synthesized, and show superior optical power limiting (OPL)/optical transparency trade-offs. By tailoring the electronic properties of the aryleneethynylene group, distinct electronic structures for these metalated complexes can be obtained, which significantly affect their photophysical behavior and OPL properties for a nanosecond laser pulse at 532,nm. Electronic influence of the ligand type and the molecular symmetry of metal group on the optical transparency/nonlinearity optimization is thoroughly elucidated. Generally, aryleneethynylene ligands with , electron-accepting nature will effectively enhance the harvesting efficiency of the triplet excited states. The ligand variation to the OPL strength of these Pt(II) compounds follows the order: DPtD,>,DPtA,>,APtA. These results could be attributed to the distinctive excited state character induced by their different electronic structures, on the basis of the data from both photophysical studies and theoretical calculations. All of the complexes show very good optical transparencies in the visible-light region and exhibit excellent OPL responses with very impressive figure of merit ,ex/,o values (up to 17), which remarkably outweigh those of state-of-the-art reverse saturable absorption dyes such as C60 and metallophthalocyanines with very poor transparencies. Their lower optical-limiting thresholds (0.05,J,cm,2 at 92% linear transmittance) compared with that of the best materials (ca. 0.07,J,cm,2 for InPc and PbPc dyes) currently in use will render these highly transparent materials promising candidates for practical OPL devices for the protection of human eyes and other delicate electro-optic sensors. [source]

Microstructural Evolution in Some Silicate Glass,Ceramics: A Review

JOURNAL OF THE AMERICAN CERAMIC SOCIETY, Issue 3 2008
Linda R. Pinckney
Just as the microstructures in glass,ceramics encompass the range from nanocrystalline transparent materials to microcrystalline tough materials, so the paths of microstructural evolution in glass,ceramics vary widely. Evolution can proceed in numerous ways, their genesis being a perturbation of some type, including the surface nucleation used in glass frit processing, crystallization of the primary phase or phases upon distinct crystalline nuclei, and nucleation promoted by nano- or microscale amorphous phase separation in the parent glass. Examples of the crystallization history of several glass,ceramic materials are described, with emphasis on how their microstructural evolution influences their ultimate physical and optical properties. [source]

Three-dimensional femtosecond laser micromachining of photosensitive glass for biomicrochips

LASER & PHOTONICS REVIEWS, Issue 3 2010
K. Sugioka
Abstract Internal modification of transparent materials such as glass can be carried out using multiphoton absorption induced by a femtosecond (fs) laser. The fs-laser modification followed by thermal treatment and successive chemical wet etching in a hydrofluoric (HF) acid solution forms three-dimensional (3D) hollow microstructures embedded in photosensitive glass. This technique is a powerful method for directly fabricating 3D microfluidic structures inside a photosensitive glass microchip. We used fabricated microchips, referred to as a nanoaquarium, for dynamic observations of living microorganisms. In addition, the present technique can also be used to form microoptical components such as micromirrors and microlenses inside the photosensitive glass, since the fabricated structures have optically flat surfaces. The integration of microfluidics and microoptical components in a single glass chip yields biophotonic microchips, in other words, optofluidics, which provide high sensitivity in absorption and fluorescence measurements of small volumes of liquid samples. [source]

Laser fluence and shot number dependence of laser-induced optical properties modification of transparent materials

LASER PHYSICS LETTERS, Issue 12 2006
K. Jamshidi-Ghaleh
Abstract Micro-fabrication in transparent materials by femtosecond laser-induced modification of the optical properties inside transparent materials, preferentially optical glasses, has received much attention. Ultra short laser pulses are capable of inducing these modifications without cracking or even melting the glasses. This kind of modification, which appears as darkening inside glass relates to the trapped electrons or holes at defect sites in the glass matrix. The femtosecond laser technology allows controlling and modifying the optical properties of glasses on a sub-micrometer scale. Laser fluence and laser shot number are important parameters for femtosecond laser-induced modification of glasses. This paper presents the 800 nm femtosecond laser-induced optical modification inside soda lime glasses at different laser fluence levels and laser shot numbers. Modification thresholds at different applied laser fluences and shot numbers are measured. Pulse energy accumulation model is proposed to predict the behaviour of darkened area spots with applied laser fluence and shot numbers. Our experimental results and the pulse energy accumulation model are in good agreement. (© 2006 by Astro, Ltd. Published exclusively by WILEY-VCH Verlag GmbH & Co. KGaA) [source]

A narrow band, green-red colour centre laser in LiF fabricated by femtosecond laser pulses

PHYSICA STATUS SOLIDI (A) APPLICATIONS AND MATERIALS SCIENCE, Issue 3 2007
T. Kurobori
Abstract Recent advances in high-intensity femtosecond (fs) laser pulses have made it possible to encode non-erasable functional micro-structures inside almost any type of photo-insensitive transparent materials. We focus our attention on bulk lithium fluoride (LiF) because of its broad emission band from the green-to-red spectral range under excitation of a single absorption band at about 450 nm. Here a room temperature, visible laser action in LiF from a distributed-feedback laser with embedded fine-pitched gratings written by fs pulses and from a laser-active colour centre laser with multilayer dielectric mirrors has been demonstrated. (© 2007 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source]

Quantitative Analysis of Human Platelet Adhesions Under a Small-Scale Flow Device

ARTIFICIAL ORGANS, Issue 4 2010
Katsuko S. Furukawa
Abstract To realize real-time evaluation of human platelet adhesions onto material surfaces with small volumes of human platelet suspensions, we developed an apparatus consisting of a modified cone and plate-type viscometer, combined with an upright epi-fluorescence microscope. The apparatus allowed real-time evaluation of platelet,material interactions and the initial event of thrombus formation, using small platelet suspension volumes (7.5 µL) under shear flow conditions. To study the dynamic behavior of platelet,material interaction, we chose five representative opaque and transparent materials: acrylate resin (AC), polytetrafluoroethylene (PTFE), polyvynylchrolide (PVC), glass, and a monolayer of human normal umbilical cord vein endothelial cells (EC) on glass under shear flow conditions. The values of adhesiveness of human platelets to the test materials in descending order were as follows: AC > PTFE > PVC > glass > human EC. Under this new small-scale flow system, we could obtain highly reproducible data, which were comparable with results from a previously developed large-scale flow system. Therefore, the newly developed cone and plate-type rheometer is a useful instrument for testing and screening materials, and allows precise quantitative evaluation of human platelet adhesion. [source]

Magnifying Superlenses and other Applications of Plasmonic Metamaterials in Microscopy and Sensing

CHEMPHYSCHEM, Issue 4 2009
Igor I. Smolyaninov Dr.
Abstract Every last detail: New advances in the construction of metamaterials enable the creation of artificial optical media, whose use in microscopy can provide resolution that is not determined by the conventional diffraction limit. The picture shows a superposition of an AFM image of a plasmonic metamaterial onto the corresponding optical image obtained using a conventional optical microscope. Over the past century, the resolution of conventional optical microscopes, which rely on optical waves that propagate into the far field, has been limited because of diffraction to a value of the order of a half-wavelength (,0/2) of the light used. Although immersion microscopes have slightly improved resolution, of the order of ,0/2n, the increased resolution is limited by the small range of refractive indices n of available transparent materials. However, now we are experiencing a quick demolition of the diffraction limit in optical microscopy. In the last few years, numerous nonlinear optical microscopy techniques based on photoswitching and saturation of fluorescence have demonstrated far-field resolution of 20 to 30 nm. In a parallel development, recent progress in metamaterials has demonstrated that artificial optical media can be created, whose use in microscopy can provide resolution that is not determined by the conventional diffraction limit. The resolution of linear immersion microscopes based on such metamaterials is only limited by losses, which can be minimized by appropriate selection of the constituents of the metamaterials used and by the wavelength(s) used for imaging. It is also feasible to compensate for losses by adding gain to the structure. Thus, optical microscopy is quickly moving towards resolution of around 10 nm, which should bring about numerous revolutionary advances in lithography and imaging. [source]