Inorganic-Polymer Nanocomposites for Optical Applications

2006 ◽  
Author(s):  
H. Du ◽  
S. H. Ng ◽  
K. T. Neo ◽  
M. Ng ◽  
I. S. Altman ◽  
...  
Keyword(s):  
Surface Modification ◽  
Optical Sensors ◽  
Protective Coatings ◽  
Functional Materials ◽  
Optical Data Storage ◽  
Inorganic Materials ◽  
Planar Waveguides ◽  
Optical Data ◽  
Inorganic Particles ◽  
Wide Range

The combination of organic and inorganic materials forms unique composites with properties that neither of the two components provides. Such functional materials are considered innovative advanced materials that enable applications in many fields, including optics, electronics, separation membranes, protective coatings, catalysis, sensors, biotechnology, and others. The challenge of incorporating inorganic particles into an organic matrix still remains today, especially for nanoparticles, due to the difficulties in their dispersion, de-agglomeration and surface modification. NanoGram has pioneered a nanomaterials synthesis technology based on laser pyrolysis process to produce a wide range of crystalline nanomaterials including complex metal oxides, nitrides and sulfides and with precisely controlled compositions, crystal structure, particle size and size distributions. In this paper we will present some examples of nanocomposites prepared using different polymer host materials and phase-pure rutile TiO2. The inorganic component can be dispersed at higher 50 weight percent into the polymer matrix. We have demonstrated a 0.2–0.3 increase of refractive index in the composite over that of host polymer while maintaining high optical transparency. These nanocomposites can be used in a range of applications or optical devices, such as planar waveguides, flat panel displays, optical sensors, high-brightness LEDs, diffraction gratings and optical data storage. Experimental data on TiO2 nanoparticle characterization, dispersion technique, surface modification and will be presented and nanocomposite properties discussed.

scholarly journals Structural and optical properties of amorphous Si–Ge–Te thin films prepared by combinatorial sputtering

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
C. Mihai ◽  
F. Sava ◽  
I. D. Simandan ◽  
A. C. Galca ◽  
I. Burducea ◽  
...  
Keyword(s):  
Optical Properties ◽  
Data Storage ◽  
Optical Sensors ◽  
Material Selection ◽  
Functional Materials ◽  
Stability Study ◽  
Optical Data Storage ◽  
Optical Data ◽  
Structural And Optical Properties ◽  
Topological Constraint

AbstractThe lack of order in amorphous chalcogenides offers them novel properties but also adds increased challenges in the discovery and design of advanced functional materials. The amorphous compositions in the Si–Ge–Te system are of interest for many applications such as optical data storage, optical sensors and Ovonic threshold switches. But an extended exploration of this system is still missing. In this study, magnetron co-sputtering is used for the combinatorial synthesis of thin film libraries, outside the glass formation domain. Compositional, structural and optical properties are investigated and discussed in the framework of topological constraint theory. The materials in the library are classified as stressed-rigid amorphous networks. The bandgap is heavily influenced by the Te content while the near-IR refractive index dependence on Ge concentration shows a minimum, which could be exploited in applications. A transition from a disordered to a more ordered amorphous network at 60 at% Te, is observed. The thermal stability study shows that the formed crystalline phases are dictated by the concentration of Ge and Te. New amorphous compositions in the Si–Ge–Te system were found and their properties explored, thus enabling an informed and rapid material selection and design for applications.

scholarly journals Bio-Templating: An Emerging Synthetic Technique for Catalysts. A Review

Catalysts ◽  
2021 ◽  
Vol 11 (11) ◽  
pp. 1364
Author(s):  
M. Carmen Herrera-Beurnio ◽  
Jesús Hidalgo-Carrillo ◽  
Francisco J. López-Tenllado ◽  
Juan Martin-Gómez ◽  
Rafael C. Estévez ◽  
...  
Keyword(s):  
Active Sites ◽  
Experimental Studies ◽  
Functional Materials ◽  
Inorganic Materials ◽  
Hierarchical Organization ◽  
Materials Synthesis ◽  
Energy Capture ◽  
Wide Range ◽  
Mineralization Processes ◽  
And Storage

In the last few years, researchers have focused their attention on the synthesis of new catalyst structures based on or inspired by nature. Biotemplating involves the transfer of biological structures to inorganic materials through artificial mineralization processes. This approach offers the main advantage of allowing morphological control of the product, as a template with the desired morphology can be pre-determined, as long as it is found in nature. This way, natural evolution through millions of years can provide us with new synthetic pathways to develop some novel functional materials with advantageous properties, such as sophistication, miniaturization, hybridization, hierarchical organization, resistance, and adaptability to the required need. The field of application of these materials is very wide, covering nanomedicine, energy capture and storage, sensors, biocompatible materials, adsorbents, and catalysis. In the latter case, bio-inspired materials can be applied as catalysts requiring different types of active sites (i.e., redox, acidic, basic sites, or a combination of them) to a wide range of processes, including conventional thermal catalysis, photocatalysis, or electrocatalysis, among others. This review aims to cover current experimental studies in the field of biotemplating materials synthesis and their characterization, focusing on their application in heterogeneous catalysis.

scholarly journals Estimating 500-m Resolution Soil Moisture Using Sentinel-1 and Optical Data Synergy

Water ◽  
2020 ◽  
Vol 12 (3) ◽  
pp. 866 ◽  
Author(s):  
Myriam Foucras ◽  
Mehrez Zribi ◽  
Clément Albergel ◽  
Nicolas Baghdadi ◽  
Jean-Christophe Calvet ◽  
...  
Keyword(s):  
Soil Moisture ◽  
Optical Sensors ◽  
Surface Soil ◽  
Remote Sensing Data ◽  
Climatic Conditions ◽  
Optical Data ◽  
Surface Soil Moisture ◽  
Moisture Index ◽  
Wide Range ◽  
Moderate Resolution Imaging Spectroradiometer

The aim of this study is to estimate surface soil moisture at a spatial resolution of 500 m and a temporal resolution of at least 6 days, by combining remote sensing data from Sentinel-1 and optical data from Sentinel-2 and MODIS (Moderate-Resolution Imaging Spectroradiometer). The proposed methodology is based on the change detection technique, applied to a series of measurements over a three-year period (2015 to 2018). The algorithm described here as “Soil Moisture Estimations from the Synergy of Sentinel-1 and optical sensors (SMES)” proposes different options, allowing information from vegetation densities and seasonal conditions to be taken into account. The output from this algorithm is a moisture index ranging between 0 and 1, with 0 corresponding to the driest soils and 1 to the wettest soils. This methodology has been tested at different test sites (South of France, Central Tunisia, Western Benin and Southwestern Niger), characterized by a wide range of different climatic conditions. The resulting surface soil moisture estimations are compared with in situ measurements and already existing satellite-derived soil moisture ASCAT (Advanced SCATterometer) products. They are found to be well correlated, for the African regions in particular (RMSE below 6 vol.%). This outcome indicates that the proposed algorithm can be used with confidence to estimate the surface soil moisture of a wide range of climatically different sites.

scholarly journals Metasurface Holography in the Microwave Regime

Photonics ◽  
2021 ◽  
Vol 8 (5) ◽  
pp. 135
Author(s):  
Guanyu Shang ◽  
Zhuochao Wang ◽  
Haoyu Li ◽  
Kuang Zhang ◽  
Qun Wu ◽  
...  
Keyword(s):  
Data Storage ◽  
Research Field ◽  
Optical Data Storage ◽  
Optical Data ◽  
Optical Fields ◽  
Holographic Imaging ◽  
Wide Range ◽  
Critical Issues ◽  
Optical Applications ◽  
Microwave Regime

Hologram technology has attracted a great deal of interest in a wide range of optical fields owing to its potential use in future optical applications, such as holographic imaging and optical data storage. Although there have been considerable efforts to develop holographic technologies using conventional optics, critical issues still hinder their future development. A metasurface, as an emerging multifunctional device, can manipulate the phase, magnitude, polarization and resonance properties of electromagnetic fields within a sub-wavelength scale, opening up an alternative for a compact holographic structure and high imaging quality. In this review paper, we first introduce the development history of holographic imaging and metasurfaces, and demonstrate some applications of metasurface holography in the field of optics. We then summarize the latest developments in holographic imaging in the microwave regime. These functionalities include phase- and amplitude-based design, polarization multiplexing, wavelength multiplexing, spatial asymmetric propagation, and a reconfigurable mechanism. Finally, we conclude briefly on this rapidly developing research field and present some outlooks for the near future.

From biominerals to biomaterials: the role of biomolecule–mineral interactions

2009 ◽  
Vol 37 (4) ◽  
pp. 687-691 ◽  
Author(s):  
Carole C. Perry ◽  
Siddharth V. Patwardhan ◽  
Olivier Deschaume
Keyword(s):  
Molecular Level ◽  
Computational Simulation ◽  
Functional Materials ◽  
Inorganic Materials ◽  
Thermal Methods ◽  
Wide Range ◽  
Solution Methods ◽  
Colloidal Species ◽  
Drug Handling

Interactions between inorganic materials and biomolecules at the molecular level, although complex, are commonplace. Examples include biominerals, which are, in most cases, facilitated by and in contact with biomolecules; implantable biomaterials; and food and drug handling. The effectiveness of these functional materials is dependent on the interfacial properties, i.e. the extent of molecular level ‘association’ with biomolecules. The present article gives information on biomolecule–inorganic material interactions and illustrates our current understanding using selected examples. The examples include (i) mechanism of biointegration: the role of surface chemistry and protein adsorption, (ii) towards improved aluminium-containing materials, and (iii) understanding the bioinorganic interface: experiment and modelling. A wide range of experimental techniques (microscopic, spectroscopic, particle sizing, thermal methods and solution methods) are used by the research group to study interactions between (bio)molecules and molecular and colloidal species that are coupled with computational simulation studies to gain as much information as possible on the molecular-scale interactions. Our goal is to uncover the mechanisms underpinning any interactions and to identify ‘rules’ or ‘guiding principles’ that could be used to explain and hence predict behaviour for a wide range of (bio)molecule–mineral systems.

scholarly journals Active analog tuning of the phase of light in the visible regime by bismuth-based metamaterials

Nanophotonics ◽  
2020 ◽  
Vol 9 (4) ◽  
pp. 885-896 ◽  
Author(s):  
Marina Garcia-Pardo ◽  
Eva Nieto-Pinero ◽  
Amanda K. Petford-Long ◽  
Rosalia Serna ◽  
Johann Toudert
Keyword(s):  
Data Storage ◽  
Optical Memory ◽  
Visible Spectral Region ◽  
Optical Data Storage ◽  
Optical Data ◽  
Photonic Switching ◽  
Active Analog ◽  
Wide Range ◽  
Analog Approach ◽  
Solid Liquid

AbstractThe active and analog tuning of the phase of light by metamaterials is needed to boost the switching performance of photonic devices. However, demonstrations of this type of tuning in the pivotal visible spectral region are still scarce. Herein, we report the active analog tuning of the phase of visible light reflected by a bismuth (Bi)-based metamaterial, enabled by a reversible solid-liquid transition. This metamaterial, fabricated by following a lithography-free approach, consists of two-dimensional assemblies of polydisperse plasmonic Bi nanostructures embedded in a refractory and transparent aluminum oxide matrix. The analog tuning of the phase is achieved by the controlled heating of the metamaterial to melt a fraction of the nanostructures. A maximum tuning of 320° (1.8 π) is observed upon the complete melting of the nanostructures at 230°C. This tuning is reversible by cooling to 25°C. In addition, it presents a wide hysteretic character due to liquid Bi undercooling. This enables the phase achieved by this analog approach to remain stable over a broad temperature range upon cooling and until re-solidification occurs around 100°C. Therefore, Bi-based metamaterials are endowed with analog optical memory capabilities, which are appealing for a wide range of applications, including optical data storage with enhanced information density or bistable photonic switching with a tunable “on” state.

scholarly journals Pickering emulsions stabilized by some inorganic materials

2021 ◽  
pp. 30-49
Author(s):  
Akbota Adilbekova ◽  
Ayaulym Yertayeva
Keyword(s):  
Colloidal Particles ◽  
Metal Oxide Nanoparticles ◽  
Inorganic Materials ◽  
Pickering Emulsions ◽  
Inorganic Particles ◽  
Carbon Particles ◽  
Inorganic Substances ◽  
Wide Range ◽  
Calcium Compounds ◽  
Clay Materials

The paper presents studies of various solid stabilizers of emulsions based on inorganic materials. Inorganic colloidal particles have an advantage for obtaining of stable emulsions due to their safety for use in food, cosmetics, pharmaceutical industry and medicine. Pickering emulsions have a higher biodegradability compared to classical emulsions stabilized with surfactants. An overview of inorganic substances such as silicon dioxide, clay materials, metal and metal oxide nanoparticles, calcium compounds and carbon particles used for stabilizing of Pickering emulsions is considered. A variety of solid inorganic particles as well as modification of their surfaces by surfactants allows to obtain the stable Pickering emulsions of different types for a wide range of applications. It should be noted that despite a large number of studies, this class of disperse systems is still not studied fully; various methods of their preparation and influence of solid particle size on stability and size of emulsions droplets are shown.

Clay minerals for nanocomposites and biotechnology: surface modification, dynamics and responses to stimuli

Clay Minerals ◽  
2012 ◽  
Vol 47 (2) ◽  
pp. 205-230 ◽  
Author(s):  
H. Heinz
Keyword(s):  
Surface Modification ◽  
Clay Minerals ◽  
Clay Mineral ◽  
Self Assembly ◽  
Functional Materials ◽  
Surface Characteristics ◽  
Mineral Surface ◽  
Thermal Transitions ◽  
Wide Range ◽  
Potential Applications

AbstractClay minerals find a wide range of application in composites, paints, drilling liquids, cosmetics, and medicine. This article reviews chemical and physical properties of natural and organically modified clay minerals to understand the nanometre-scale structure, surface characteristics, and application in functional materials. The relation between fundamental properties and materials design is emphasized and illustrated by examples. The discussion comprises the following: an overview; surface structure and cation density; solubility and solubility reversal by surface modification; the degree of covalent and ionic bonding represented by atomic charges; the distribution of metal substitution sites; measurements and simulations of interfacial properties at the nanometre scale; self-assembly, packing density, and orientation of alkylammonium surfactants on the clay mineral surface; the density and chain conformation of surfactants in organic interlayer spaces; the free energy of exfoliation in polymer matrices and modifications by tuning the cleavage energy; thermal transitions, diffusion, and optical responses of surfactants on the mineral surface; elastic moduli and bending stability of clay layers; and the adsorption mechanism of peptides onto clay mineral surfaces in aqueous solution. Potential applications in biotechnology and other future uses are described.

New Photopolymers Based on Two-Photon Absorbing Chromophores and Application to Three-Dimensional Microfabrication and Optical Storage

1997 ◽  
Vol 488 ◽  
Author(s):  
B. H. Cumpston ◽  
J. E. Ehrlich ◽  
L. L. Erskin ◽  
A. A. Heikalt ◽  
Z.-Y. Hu ◽  
...  
Keyword(s):  
Charge Transfer ◽  
Data Storage ◽  
Three Dimensional ◽  
Optical Data Storage ◽  
Photon Absorption ◽  
Transfer Reactions ◽  
Optical Data ◽  
Two Photon ◽  
Wide Range ◽  
Charge Transfer Reactions

AbstractMolecules exhibiting strong two-photon absorption hold great potential for a wide range of applications including two-photon fluorescence imaging, three-dimensional (3D) optical data storage, and 3D microfabrication. We have observed two-photon absorptivities as high as 1500×10− 50 cm4 s/photon in bis-donor diphenylpolyene derivatives that are correlated to simultaneous charge transfer from the end groups to the polyene bridge in the molecule. Many of these molecules are also excellent photoexcitable electron donors that can initiate charge-transfer reactions with acrylate monomers. Marcus theory is used to describe the efficiency of these charge-transfer reactions. Polymerization rates have also been measured and we show that these twophoton chromophores display increased sensitivity and recording speed over conventional UV photo-initiators. The fabrication of complex, three-dimensional structures by twophoton polymerization is demonstrated and discussed in the context of advanced photonic applications.

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