Synthesis and Study of the Optical Properties of PMMA Microspheres and Opals

Polymethylmethacrylate (PMMA) microspheres were synthesized by surfactant-free emulsion polymerization. These microspheres were used to obtain opals by the self-assembly method. Monomer and initiator quantities were varied systematically to monitor the size of PMMA microspheres. From SEM and DLS measurements, a trend was observed showing as the monomer and initiator amounts increased the average diameter of PMMA microspheres increased except when a minimum monomer amount was reached, for which the size of the microspheres remained practically constant. Diffuse reflectance spectra were processed by the Kubelka–Munk treatment to estimate the energy band gap (Eg) of the PMMA microspheres. It was found that PMMA microspheres present an indirect transition. From SEM micrographs, it is seen that PMMA opals photonic crystals are formed by microspheres in a uniform periodic face-centered cubic (fcc) array. Variable-angle specular reflectance spectra show that the opals possess a pseudo photonic band gap (PBG) in the visible and near-IR regions. Furthermore, it was found that PBGs shift towards larger wavelengths as the average diameter of the PMMA microspheres increases.

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Photonic band gap in the face-centered cubic lattice of spherical shells connected by cylindrical tubes

Physical Review B ◽

10.1103/physrevb.72.113113 ◽

2005 ◽

Vol 72 (11) ◽

Cited By ~ 8

Author(s):

Hong-Bo Chen ◽

Yong-Zheng Zhu ◽

Yan-Ling Cao ◽

Yan-Ping Wang ◽

Yuan-Bin Chi

Keyword(s):

Band Gap ◽

Photonic Band Gap ◽

Face Centered Cubic ◽

Spherical Shells ◽

Cubic Lattice ◽

Cylindrical Tubes ◽

The Face ◽

Face Centered ◽

Photonic Band

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Preparation and Characterization of the Ordered SiO2 Colloidal Crystallization Films

Key Engineering Materials ◽

10.4028/www.scientific.net/kem.368-372.1389 ◽

2008 ◽

Vol 368-372 ◽

pp. 1389-1391 ◽

Cited By ~ 1

Author(s):

Shuan Gui Qing ◽

Bo Liu ◽

Xun Liang ◽

Hai Yang Li ◽

Wei Zhong Lv ◽

...

Keyword(s):

Self Assembly ◽

Face Centered Cubic ◽

X Ray Diffraction ◽

Assembly Method ◽

Colloidal Crystallization ◽

The Face ◽

Infrared Spectrometer ◽

Face Centered ◽

Sio2 Spheres

Multilayer SiO2 crystals modified by alkoxysilanes were fabricated by the vertical deposition technique combined with self-assembly method. The SiO2 colloidal crystallization was prepared by the traditional Stöber-Fink-Bohn method, and modified by different alkoxysilanes to investigate the properties of the films. The films fabricated by the ordering of SiO2 spheres were investigated by infrared spectrometer, X-ray diffraction, scanning electron microscope, UV-visible spectrophotometer. The results showed that thin film is the face-centered cubic structures and the spheres are [111]-oriented.

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Exploring Space Groups for Three Dimensional Photonic Band Gap Structures Via Level Set Equations: The Face Centered Cubic Lattice

MRS Proceedings ◽

10.1557/proc-788-l10.7 ◽

2003 ◽

Vol 788 ◽

Author(s):

Martin Maldovan ◽

Chaitanya K. Ullal ◽

Craig W. Carter ◽

Edwin L. Thomas

Keyword(s):

Band Gap ◽

Level Set ◽

Photonic Band Gap ◽

Band Gaps ◽

High Symmetry ◽

Face Centered Cubic ◽

Photonic Band Gaps ◽

Basic Set ◽

Face Centered ◽

Photonic Band

ABSTRACTA level set approach was used to study photonic band gaps for dielectric composites with symmetries of the eleven face centered cubic lattices. Candidate structures were modeled for each group by a 3D surface given by f(x,y,z)-t=0 obtained by equating f to an appropriate sum of structure factor terms. This approach allows us to easily map different structures and gives us an insight into the effects of symmetry, connectivity and genus on photonic band gaps. It is seen that a basic set of symmetries defines the essential band gap and connectivity. The remaining symmetry elements modify the band gap. The eleven lattices are classified into four fundamental topologies on the basis of the occupancy of high symmetry Wyckoff sites. Of the fundamental topologies studied, three display band gaps--- including two: the (F-RD) and a group 216 structure that have not been reported previously.

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THE SIZE INFLUENCE OF SILICA MICROSPHERES ON PHOTONIC BAND GAP OF PHOTONIC CRYSTALS

International Journal of Modern Physics B ◽

10.1142/s0217979207037338 ◽

2007 ◽

Vol 21 (16) ◽

pp. 2761-2768 ◽

Cited By ~ 2

Author(s):

XIYING MA ◽

ZHIJUN YAN

Keyword(s):

Photonic Crystals ◽

Band Gap ◽

Photonic Band Gap ◽

Three Dimensional ◽

Refraction Index ◽

Face Centered Cubic ◽

Silica Microspheres ◽

Large Shift ◽

Face Centered ◽

Photonic Band

The size influence of silica microspheres on the photonic band gap (PBG) of three-dimensional face-centered-cubic (fcc) photonic crystals (PCs) is studied by means of colloidal photonic crystals, which are self-assembled by the vertical deposition technique. Monodispersed SiO 2 microspheres with a diameter of 220–320 nm are synthesized using tetraethylorthosilicate (TEOS) as a precursor material. We find that the PBG of the PCs shifts from 450 nm to 680 nm with silica spheres increasing from 220 to 320 nm. In addition, the PBG moves to higher photon energy when the samples are annealed in a temperature range of 200–700°C. The large shift results from the decrease in refraction index of silica due to moisture evaporation.

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A hollow spherical non-closed-packed face-centered cubic uniaxial structure with a photonic band gap

Physics Letters A ◽

10.1016/j.physleta.2007.02.046 ◽

2007 ◽

Vol 369 (1-2) ◽

pp. 124-127 ◽

Cited By ~ 2

Author(s):

Yan-Ling Cao ◽

Yong-Zheng Zhu ◽

Zhi-Hui Li ◽

Juan Ding ◽

Jun-Song Liu ◽

...

Keyword(s):

Band Gap ◽

Photonic Band Gap ◽

Face Centered Cubic ◽

Face Centered ◽

Photonic Band

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Fabricación y caracterización óptica de cristales coloidales de alta calidad formados por esferas de SiO2 de 225 nm de diámetro con empaquetamiento fcc crecidos por el método convectivo de auto-ensamblado de deposición vertical.

Universitas Scientiarum ◽

10.11144/javeriana.sc15-2.faoc ◽

2010 ◽

Vol 15 (2) ◽

pp. 150 ◽

Cited By ~ 3

Author(s):

Octavio Alejandro Castañeda-Uribe ◽

Juan Carlos Salcedo-Reyes ◽

Henry Alberto Méndez-Pinzón ◽

Aura Marina Pedroza-Rodríguez

Keyword(s):

Photonic Crystals ◽

Self Assembly ◽

Volume Fraction ◽

Colloidal Crystals ◽

Optical Characterization ◽

Bragg Diffraction ◽

Face Centered Cubic ◽

High Quality ◽

Assembly Method ◽

Face Centered

Objective: Fabrication and optical characterization of close-packed 225 nm SiO2 -based colloidal crystals. Materials and methods: The vertical convective self-assembly method is used to grow high-quality 225 nm close-packed SiO2-based colloidal crystals. An annealing process (550°C) is made in order to improve the mechanical stability of the sample. Optical characterization is done by angle-resolved transmission spectroscopy (A-RTS) and structural characterization by Scanning Electron Microscopy (SEM). Results: Both, A-RTS and SEM, show that with the vertical convective self-assembly method, with the appropriate parameters of temperature of evaporation (60°C), volume fraction of the colloidal suspension (0.2% w/w) and acidity (pH=6), highly ordered close packed face centered cubic (fcc) SiO2 based colloidal crystals are obtained. Conclusions: The growth of high-quality (long range order and defect-free) face centered cubic opal-based photonic crystals is reported. Key words: Photonic crystals, colloidal crystals, artificial opals, vertical convective deposition method, Bragg diffraction

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Synthesis and Self-Assembly of Films Containing FeCoPt Nanoparticles

MRS Proceedings ◽

10.1557/proc-674-u4.7 ◽

2001 ◽

Vol 674 ◽

Cited By ~ 1

Author(s):

Min Chen ◽

David E. Nikles

Keyword(s):

Self Assembly ◽

Annealing Temperature ◽

Chemical Reduction ◽

Average Diameter ◽

Iron Pentacarbonyl ◽

Face Centered Cubic ◽

Oxidized Iron ◽

Carbon Coated ◽

Face Centered ◽

Cobalt Acetylacetonate

ABSTRACTFe49Co7Pt44 and Fe40Co17Pt43nanoparticles were synthesized by simultaneous chemical reduction of platinum acetylacetonate and cobalt acetylacetonate and thermal decomposition of iron pentacarbonyl. As-prepared the particles had a disordered face-centered cubic lattice with an average diameter of 3.2 nm and were superparamagnetic. These particles were well dispersed in a 50/50 mixture of hexane and octane. The particles self-assembled into ordered superlattices when deposited onto carbon coated Cu TEM grids or onto single crystal Si (100) substrates. After vacuum annealing (from 500°C to 700 °C), the particles transformed to the tetragonal phase. The coercivity of the film strongly depended on the composition and annealing temperature. For the Fe49Co7Pt44film, coercivity of 8700 Oe and a squareness of 0.75 after annealing at 700 °C for 30 minutes. XPS shows existance of oxidized iron and cobalt on the surface of film.

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Fabrication and Optical Properties of Nb2O5 Inverse Opal Photonic Crystals by PS Opal Template

Materials Science Forum ◽

10.4028/www.scientific.net/msf.688.90 ◽

2011 ◽

Vol 688 ◽

pp. 90-94 ◽

Cited By ~ 1

Author(s):

Y.Q. Yang ◽

P.D. Han ◽

Y.P. Li ◽

M.H. Dong ◽

L.L. Zhang ◽

...

Keyword(s):

Band Gap ◽

Photonic Band Gap ◽

Face Centered Cubic ◽

Inverse Opal ◽

Void Space ◽

Inverse Opal Structure ◽

Calculation Results ◽

Face Centered ◽

Vertical Deposition Method ◽

Photonic Band

In this paper, polystyrene (PS) opals template, opal with a closed-packed face centered cubic (fcc) lattice, was prepared using vertical deposition method. The template provided void space for infiltration of Nb2O5 etc. PS colloidal nanospheres was face-centered-cubic (FCC) structure with its (111) planes parallel to the substrate. Finally, the transfer matrix method (TMM) was used to calculate photonic band-gap of PS opal and Nb2O5 inverse opal structure. The calculation results show that the photonic band-gap of Nb2O5 with inverse opal structure is wider than that of PS opals.

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Enhanced sunlight photocatalytic activity and biosafety of marine-driven synthesized cerium oxide nanoparticles

Scientific Reports ◽

10.1038/s41598-021-94327-w ◽

2021 ◽

Vol 11 (1) ◽

Author(s):

Somayeh Safat ◽

Foad Buazar ◽

Salim Albukhaty ◽

Soheila Matroodi

Keyword(s):

Photocatalytic Activity ◽

Band Gap ◽

Color Change ◽

Removal Rate ◽

Average Crystallite Size ◽

Face Centered Cubic ◽

One Pot ◽

Stabilizing Agents ◽

Face Centered ◽

Living Organisms

AbstractThis contribution presents the biosynthesis, physiochemical properties, toxicity and photocatalytic activity of biogenic CeO2 NPs using, for the first time, marine oyster extract as an effective and rich source of bioreducing and capping/stabilizing agents in a one-pot recipe. CeO2 NPs formation was initially confirmed through the color change from light green to pale yellow and subsequently, their corresponding absorption peak was spectroscopically determined at 310 nm with an optical band-gap of 4.67 eV using the DR-UV technique. Further, XRD and Raman analyses indicated that nanoceria possessed face-centered cubic arrangements without any impurities, having an average crystallite size of 10 nm. TEM and SEM results revealed that biogenic CeO2 NPs was approximately spherical in shape with a median particle size of 15 ± 1 nm. The presence of various bioorganic substances on the surface of nanoparticles was deduced by FTIR and TGA results. It is found that marine-based nanoceria shows no cytotoxic effect on the normal cell, thus indicating their enhanced biocompatibility and biosafety to living organisms. Environmentally, due to energy band gap, visible light-activated CeO2 nanocatalyst revealed superior photocatalytic performance on degradation of methylene blue pollutant with removal rate of 99%. Owing to the simplicity, cost-effectiveness, and environmentally friendly nature, this novel marine biosynthetic route paves the way for prospective applications of nanoparticles in various areas.

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Preparation and characterization of poly(styrenemethacrylic acid)/MCM-41 core/shell nanocomposite microspheres

e-Polymers ◽

10.1515/epoly.2009.9.1.1433 ◽

2009 ◽

Vol 9 (1) ◽

Author(s):

Yansheng Zhao ◽

Xingji Ma ◽

Yongmei Liu ◽

Guangwei Yuan ◽

Meijuan Guo ◽

...

Keyword(s):

Self Assembly ◽

Cetyltrimethylammonium Bromide ◽

Average Diameter ◽

Molar Ratio ◽

Core Shell ◽

Acidic Media ◽

Assembly Method ◽

20 Nm ◽

Mcm 41

AbstractIn acidic media, poly(styrene-methacrylic acid)/MCM-41 [P(St- MAA)/MCM-41] core/shell microspheres were synthesized using monodisperse P(St-MAA) particles contained in soap-free emulsion and cetyltrimethylammonium bromide as co-templates by adsorption self-assembly method. The effects of P(St- MAA) composition on shell structure of the core/shell microspheres were investigated. The morphology and composition of P(St-MAA)/MCM-41 microspheres were characterized by TEM, XRD and FTIR. The results show that the ordering degree of MCM-41 shells increased as the molar ratio of MAA to St increased. When n(MAA)/n(St) is 0.2, the average diameter and the shell thickness of nanocomposite microspheres are about 170 nm and 20 nm, respectively.

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