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Sample records for mesoporous silica-magnetite nanocomposite

  1. Mesoporous silica magnetite nanocomposite synthesized by using a neutral surfactant

    NASA Astrophysics Data System (ADS)

    Souza, K. C.; Salazar-Alvarez, G.; Ardisson, J. D.; Macedo, W. A. A.; Sousa, E. M. B.

    2008-05-01

    Magnetite nanoparticles coated by mesoporous silica were synthesized by an alternative chemical route using a neutral surfactant and without the application of any functionalization method. The magnetite (Fe3O4) nanoparticles were prepared by precipitation from aqueous media, and then coated with mesoporous silica by using nonionic block copolymer surfactants as the structure-directing agents. The mesoporous SiO2-coated Fe3O4 samples were characterized by x-ray diffraction, Fourier-transform infrared spectroscopy, N2 adsorption-desorption isotherms, transmission electron microscopy, 57Fe Mössbauer spectroscopy, and vibrating sample magnetometry. Our results revealed that the magnetite nanoparticles are completely coated by well-ordered mesoporous silica with free pores and stable (~8 nm thick) pore walls, and that the structural and magnetic properties of the Fe3O4 nanoparticles are preserved in the applied synthesis route.

  2. Synthesis, characterisation and application of silica-magnetite nanocomposites

    NASA Astrophysics Data System (ADS)

    Bruce, Ian J.; Taylor, James; Todd, Michael; Davies, Martin J.; Borioni, Enrico; Sangregorio, Claudio; Sen, Tapas

    2004-12-01

    Silica-magnetite composites were prepared for eventual applications in biomolecular separations (nucleic acids). Their production on large scale has been optimised and they have been extensively characterised in a physical and chemical context. They perform at least as well, if not better than a commercially available equivalent at adsorbing and eluting DNA. Several methods for the preparation of magnetite were compared in order to select one, which produced particles, possessing high magnetic susceptibility, low rate of sedimentation and good chemical stability. Of the main methods studied: (i) oxidative hydrolysis of iron(II) sulphate in alkaline media, (ii) alkaline hydrolysis of iron(II) and iron(III) chloride solutions, and (iii) precipitation from iron(II) and iron(III) chloride solutions by hydrolysis of urea, method (i) produced the 'best' magnetite particles. Silica-magnetite composites were prepared using the 'best' magnetite, and, for comparison, two methods for depositing silica were used to coat the silica onto magnetite nanoparticles, from silicic acid at pH 10 and by acid hydrolysis of tetraethoxysilane (TEOS) at 90 °C. The best method for yielding silica-magnetite composites that worked well in DNA adsorption and elution proved to be that involving silicic acid and this material could be made in 20 g batch sizes. Silica-magnetite composites from the two methods proved to have distinct and different physical and chemical properties. All magnetite and silica-magnetite samples were fully characterised for their relative chemical composition using Fourier-transform infrared, XRF and thermo-gravimetric analysis. Their physical characteristics were determined using scanning electron microscopy and N2 adsorption and Mossbauer spectroscopy was used to confirm the identity of the iron oxides produced. Selected samples were comparatively tested for their ability to adsorb, and subsequently elute, 2-deoxyguanosine-5-monophosphate (GMP) and its non

  3. Application of silica magnetite nanocomposites to the isolation of ultrapure plasmid DNA from bacterial cells

    NASA Astrophysics Data System (ADS)

    Chiang, Chen-Li; Sung, Ching-Shan; Chen, Chuh-Yean

    2006-10-01

    The aim of this study was to develop a simple and rapid method for purification of ultrapure plasmid DNA with high yields from bacterial cultures. Nanosized superparamagnetic nanoparticles (Fe 3O 4) were prepared by chemical precipitation method using Fe 2+, Fe 3+ salt, and ammonium hydroxide under a nitrogen atmosphere. Silica-magnetite nanocomposites were prepared by the method of acid hydrolysis of tetraethoxysilane (TEOS) to coat the silica onto magnetite nanoparticles. DNA was adsorbed to the support under high salt conditions, and recovered directly in water for immediate downstream application, without the need for precipitation. We demonstrated that a useful plasmid, pRSETB-EGFP, encoding for the green fluorescent protein with T7 promoter, could be amplified in Escherichia coli of DE3 strain. Up to approximately 43 μg of high-purity ( A260/ A280 ratio=1.75) plasmid DNA was isolated from 3 ml of an overnight bacterial culture. The eluted plasmid DNA was used directly for restriction enzyme digestion, bacterial cell transformation and polymerase chain reaction (PCR) amplification with success. The protocol, starting from the preparation of bacterial lysate and ending with purified plasmid takes less than 8 min. The silica-magnetite nanocomposites deliver significant time-savings, overall higher yields, lower RNA contamination, and better PCR amplification compared to commercial available silica-based and other methods.

  4. Mesoporous metal oxide graphene nanocomposite materials

    DOEpatents

    Liu, Jun; Aksay, Ilhan A.; Kou, Rong; Wang, Donghai

    2016-05-24

    A nanocomposite material formed of graphene and a mesoporous metal oxide having a demonstrated specific capacity of more than 200 F/g with particular utility when employed in supercapacitor applications. A method for making these nanocomposite materials by first forming a mixture of graphene, a surfactant, and a metal oxide precursor, precipitating the metal oxide precursor with the surfactant from the mixture to form a mesoporous metal oxide. The mesoporous metal oxide is then deposited onto a surface of the graphene.

  5. A highly ordered cubic mesoporous silica/graphene nanocomposite.

    PubMed

    Lee, Chang-Wook; Roh, Kwang Chul; Kim, Kwang-Bum

    2013-10-21

    A highly ordered cubic mesoporous silica (KIT-6)/graphene nanocomposite and 2D KIT-6 nanoflakes were synthesized using a novel synthesis methodology. The non-ionic triblock copolymer, P123, played a dual role as a structure-directing agent in the formation of the cubic mesoporous structure and as a cross-linking agent between mesoporous silica and graphene. The prepared (KIT-6)/graphene nanocomposite could act as a template for the preparation of mesoporous material/graphene nanocomposites. PMID:24057016

  6. A highly ordered cubic mesoporous silica/graphene nanocomposite

    NASA Astrophysics Data System (ADS)

    Lee, Chang-Wook; Roh, Kwang Chul; Kim, Kwang-Bum

    2013-09-01

    A highly ordered cubic mesoporous silica (KIT-6)/graphene nanocomposite and 2D KIT-6 nanoflakes were synthesized using a novel synthesis methodology. The non-ionic triblock copolymer, P123, played a dual role as a structure-directing agent in the formation of the cubic mesoporous structure and as a cross-linking agent between mesoporous silica and graphene. The prepared (KIT-6)/graphene nanocomposite could act as a template for the preparation of mesoporous material/graphene nanocomposites.A highly ordered cubic mesoporous silica (KIT-6)/graphene nanocomposite and 2D KIT-6 nanoflakes were synthesized using a novel synthesis methodology. The non-ionic triblock copolymer, P123, played a dual role as a structure-directing agent in the formation of the cubic mesoporous structure and as a cross-linking agent between mesoporous silica and graphene. The prepared (KIT-6)/graphene nanocomposite could act as a template for the preparation of mesoporous material/graphene nanocomposites. Electronic supplementary information (ESI) available: S1: TEM images of disordered mesoporous silica/graphene nanocomposite; S2: TEM images of KIT-6/GO nanocomposite; S3: Thermogravimetric analysis of KIT-6/GO and KG-400-700; S4: SEM and TEM images of KIT-6; S5: Low angle XRD, Raman spectra, N2 adsorption isotherms, pore size distribution and photographic images of the prepared samples; S6: TEM image and N2 adsorption isotherms of mesoporous carbon/graphene nanocomposite; S7: XPS C1s spectra of the prepared samples. See DOI: 10.1039/c3nr03108j

  7. Multifunctional mesoporous silica nanocomposite nanoparticles for theranostic applications.

    PubMed

    Lee, Ji Eun; Lee, Nohyun; Kim, Taeho; Kim, Jaeyun; Hyeon, Taeghwan

    2011-10-18

    Clever combinations of different types of functional nanostructured materials will enable the development of multifunctional nanomedical platforms for multimodal imaging or simultaneous diagnosis and therapy. Mesoporous silica nanoparticles (MSNs) possess unique structural features such as their large surface areas, tunable nanometer-scale pore sizes, and well-defined surface properties. Therefore, they are ideal platforms for constructing multifunctional materials that incorporate a variety of functional nanostructured materials. In this Account, we discuss recent progress by our group and other researchers in the design and fabrication of multifunctional nanocomposite nanoparticles based on mesoporous silica nanostructures for applications to simultaneous diagnosis and therapy. Versatile mesoporous silica-based nanocomposite nanoparticles were fabricated using various methods. Here, we highlight two synthetic approaches: the encapsulation of functional nanoparticles within a mesoporous silica shell and the assembly of nanoparticles on the surface of silica nanostructures. Various nanoparticles were encapsulated in MSNs using surfactants as both phase transfer agents and pore-generating templates. Using MSNs as a scaffold, functional components such as magnetic nanoparticles and fluorescent dyes have been integrated within these systems to generate multifunctional nanocomposite systems that maintain their individual functional characteristics. For example, uniform mesoporous dye-doped silica nanoparticles immobilized with multiple magnetite nanocrystals on their surfaces have been fabricated for their use as a vehicle capable of simultaneous magnetic resonance (MR) and fluorescence imaging and drug delivery. The resulting nanoparticle-incorporated MSNs were then tested in mice with tumors. These in vivo experiments revealed that these multifunctional nanocomposite nanoparticles were delivered to the tumor sites via passive targeting. These nanocomposite

  8. Gyroidal mesoporous multifunctional nanocomposites via atomic layer deposition

    NASA Astrophysics Data System (ADS)

    Werner, Jörg G.; Scherer, Maik R. J.; Steiner, Ullrich; Wiesner, Ulrich

    2014-07-01

    We demonstrate the preparation of rationally designed, multifunctional, monolithic and periodically ordered mesoporous core-shell nanocomposites with tunable structural characteristics. Three-dimensionally (3D) co-continuous gyroidal mesoporous polymer monoliths are fabricated from a solution-based triblock terpolymer-resol co-assembly and used as the functional templates for the fabrication of free-standing core-shell carbon-titania composites using atomic layer deposition (ALD). The deposition depth into the torturous gyroidal nanonetwork is investigated as a function of ALD conditions and the resulting composites are submitted to different thermal treatments. Results suggest that ALD can homogenously coat mesoporous templates with well defined pore sizes below 50 nm and thicknesses above 10 μm. Structural tunability like titania shell thickness and pore size control is demonstrated. The ordered nanocomposites exhibit triple functionality; a 3D continuous conductive carbon core that is coated with a crystalline titania shell that in turn is in contact with a 3D continuous mesopore network in a compact monolithic architecture. This materials design is of interest for applications including energy conversion and storage. Gyroidal mesoporous titania monoliths can be obtained through simultaneous titania crystallization and template removal in air.We demonstrate the preparation of rationally designed, multifunctional, monolithic and periodically ordered mesoporous core-shell nanocomposites with tunable structural characteristics. Three-dimensionally (3D) co-continuous gyroidal mesoporous polymer monoliths are fabricated from a solution-based triblock terpolymer-resol co-assembly and used as the functional templates for the fabrication of free-standing core-shell carbon-titania composites using atomic layer deposition (ALD). The deposition depth into the torturous gyroidal nanonetwork is investigated as a function of ALD conditions and the resulting composites are

  9. Desalination of Basal Water by Mesoporous Carbons Nanocomposite Membrane.

    PubMed

    Choi, Jeongdong; Ahn, Youngho; Gamal El-Din, Mohamed; Kim, Eun-Sik

    2016-02-01

    The hydro-transportation process used to obtain bitumen from the Alberta oil sands produces large volume of basal depressurization water (BDW), which contains high salt concentrations. In this research, thin-film nanocomposite (TFN) membrane technology applied to treat BDW in lab-scale, and evaluated water properties before and after the treatment. The average rejection ratios of ionic species were 95.2% and 92.8% by TFN membrane (with ordered mesoporous carbons (OMCs)) and thin-film composite (TFC) (without OMCs) membrane, respectively. The turbidity and total dissolved solids (TDS) were completely rejected in all treatment conditions. Interestingly, the water flux of TFN membrane was dramatically increased compared to TFC membrane. The increase of water flux was believed to be caused by the increased membrane surface hydrophilicity and nano-pore effects by the OMCs. PMID:27433734

  10. Recyclable Magnetic Mesoporous Nanocomposite with Improved Sensing Performance toward Nitrite.

    PubMed

    Zhang, Yihe; Su, Zisheng; Li, Bin; Zhang, Liming; Fan, Di; Ma, Heping

    2016-05-18

    A magnetic nanomaterial for nitrite ion detection was demonstrated in the present study. This nanomaterial was prepared by grafting a rhodamine 6G derivative (denoted as Rh 6G-OH) into the channels of core-shell magnetic mesoporous silica nanospheres. The nanocomposite (denoted as Fe3O4@Rh 6G) showed large surface area and improved fluorescent performance to accumulate and recognize NO2(-), and its superparamagnetic behavior played an important role in reusability. The fluorescent intensity decreased linearly along with the NO2(-) concentration in the range of 1-50 μM, and the detection limit was estimated to be 0.8 μM, which was much lower than the maximum limit of nitrite ion in drinking water (65 μM) recommended by World Health Organization. Importantly, Fe3O4@Rh 6G could be magnetically collected and effectively reutilized after six test cycles. PMID:27115527

  11. White light emitting Mesoporous Carbon-Silica Nanocomposite

    NASA Astrophysics Data System (ADS)

    Matsumura, Akihiro; Ishii, Yosuke; Sato, Koji; Ishikawa, Yukari; Kawasaki, Shinji

    2011-05-01

    Visible photoluminescence (PL) from oxidized mesoporous carbon-silica nanocomposite (MPCS) prepared by the triconstituent co-assembly method is reported. White PL from MPCS was observed by naked eye at room temperature. Oxidation effects on carbon-silica bonding states and transmittance were investigated. PL intensity decreased with decreasing of carbon dangling bond density by oxidation at above 500 °C. The transmittance of MPCS at excitation and emission wavelengths increased with increasing of oxidation temperature. It is concluded that PL intensity is determined by the balance between PL related carbon density and transmittance. We proposed an additional wet oxidation that can increase PL intensity by the increase of transmittance under suppressing carbon desorption.

  12. Mesoporous crystalline-amorphous oxide nanocomposite network for high-performance lithium storage.

    PubMed

    Peng, Yiting; Chen, Zheng; Le, Zaiyuan; Xu, Qunjie; Li, Hexing; Lu, Yunfeng

    2015-08-01

    Mesoporous nanocomposites composed of crystalline and amorphous oxides network were successfully synthesized by a continuous aerosol spray process; electrodes made from such nanocomposites with a thin-layer of protective oxide coating exhibit high capacity and long cycling life for lithium storage. PMID:26121570

  13. Brick-and-Mortar Self-Assembly Approach to Graphitic Mesoporous Carbon Nanocomposites

    SciTech Connect

    Dai, Sheng; Fulvio, Pasquale F; Mayes, Richard T; Wang, Xiqing; Mahurin, Shannon Mark; Bauer, Christopher; Presser, Volker; Mcdonough, John; Gogotsi, Yury

    2011-01-01

    Mesoporous carbon materials do not have sufficient ordering at the atomic scale to exhibit good electronic conductivity. To date, mesoporous carbons having uniform mesopores and high surface areas have been prepared from partially-graphitizable precursors in the presence of templates. High temperature thermal treatments above 2000 C, which are usually required to increase conductivity, result in a partial or total collapse of the mesoporous structures and reduced surface areas induced by growth of graphitic domains, limiting their applications in electric double layer capacitors and lithium-ion batteries. In this work, we successfully implemented a 'brick-and-mortar' approach to obtain ordered graphitic mesoporous carbon nanocomposites with tunable mesopore sizes below 850 C without using graphitization catalysts or high temperature thermal treatments. Phenolic resin-based mesoporous carbons act as mortar to highly conductive carbon blacks and carbon onions (bricks). The capacitance and resistivity of final materials can be tailored by changing the mortar to brick ratios.

  14. Synthesis and microwave absorbing properties of FeNi alloy incorporated ordered mesoporous carbon-silica nanocomposite

    NASA Astrophysics Data System (ADS)

    Li, Guoxian; Guo, Yunxia; Sun, Xin; Wang, Tao; Zhou, Jianhua; He, Jianping

    2012-11-01

    Ordered mesoporous carbon-silica/FeNi nanocomposite were prepared by a sol-gel method and following sintering process. The electromagnetic parameters were measured in the 0.5-18 GHz range. Compared with ordered mesoporous carbon-silica composite, the permittivity of ordered mesoporous carbon-silica/FeNi nanocomposite decreases, while the permeability almost remains unchanged. The optimal reflection loss of ordered mesoporous carbon-silica/FeNi nanocomposite can reach -45.6 dB at 11.1 GHz for a layer thickness of 3.0 mm. The enhanced microwave absorption of the mesoporous carbon-silica/FeNi nanocomposite is due to better balance between the complex permittivity and permeability, geometrical effect, as well as multiple reflections by the ordered mesoporous structure.

  15. Chemical Insight into the Adsorption of Chromium(III) on Iron Oxide/Mesoporous Silica Nanocomposites.

    PubMed

    Egodawatte, Shani; Datt, Ashish; Burns, Eric A; Larsen, Sarah C

    2015-07-14

    Magnetic iron oxide/mesoporous silica nanocomposites consisting of iron oxide nanoparticles embedded within mesoporous silica (MCM-41) and modified with aminopropyl functional groups were prepared for application to Cr(III) adsorption followed by magnetic recovery of the nanocomposite materials from aqueous solution. The composite materials were extensively characterized using physicochemical techniques, such as powder X-ray diffraction, thermogravimetric and elemental analysis, nitrogen adsorption, and zeta potential measurements. For aqueous Cr(III) at pH 5.4, the iron oxide/mesoporous silica nanocomposite exhibited a superior equilibrium adsorption capacity of 0.71 mmol/g, relative to 0.17 mmol/g for unmodified mesoporous silica. The aminopropyl-functionalized iron oxide/mesoporous silica nanocomposites displayed an equilibrium adsorption capacity of 2.08 mmol/g, the highest adsorption capacity for Cr(III) of all the materials evaluated in this study. Energy-dispersive spectroscopy (EDS) with transmission electron microscopy (TEM) and X-ray photoelectron spectroscopy (XPS) experiments provided insight into the chemical nature of the adsorbed chromium species. PMID:26134074

  16. Controlled synthesis of uniform and monodisperse upconversion core/mesoporous silica shell nanocomposites for bimodal imaging.

    PubMed

    Liu, Jianan; Bu, Wenbo; Zhang, Shengjian; Chen, Feng; Xing, Huaiyong; Pan, Limin; Zhou, Liangping; Peng, Weijun; Shi, Jianlin

    2012-02-20

    Here we report the design and controlled synthesis of monodisperse and precisely size-controllable UCNP@mSiO(2) nanocomposites smaller than 50 nm by directly coating a mesoporous silica shell (mSiO(2)) on upconversion nanocrystals NaYF(4):Tm/Yb/Gd (UCNPs), which can be used as near-infrared fluorescence and magnetic resonance imaging (MRI) agents and a platform for drug delivery as well. Some key steps such as transferring hydrophobic UCNPs to the water phase by using cetyltrimethylammonium bromide (CTAB), removal of the excess amount of CTAB, and temperature-controlled ultrasonication treatment should be adopted and carefully monitored to obtain uniform upconversion core/mesoporous silica shell nanocomposites. The excellent performance of the core-shell-structured nanocomposite in near-infrared fluorescence and magnetic resonance imaging was also demonstrated. PMID:22252972

  17. "Bricks and mortar" self-assembly approach to graphitic mesoporous carbon nanocomposites

    SciTech Connect

    Fulvio, P. F.; Mayes, R.; Wang, X. Q.; Mahurin, S., M.; Bauer, J. C.; Presser, V.; McDonough, J.; Gogotsi, Y.; Dai, S.

    2011-04-20

    Mesoporous carbon materials do not have sufficient ordering at the atomic scale to exhibit good electronic conductivity. To date, mesoporous carbons having uniform mesopores and high surface areas have been prepared from partially-graphitizable precursors in the presence of templates. High temperature thermal treatments above 2000 °C, which are usually required to increase conductivity, result in a partial or total collapse of the mesoporous structures and reduced surface areas induced by growth of graphitic domains, limiting their applications in electric double layer capacitors and lithium-ion batteries. In this work, we successfully implemented a “brick-and-mortar” approach to obtain ordered graphitic mesoporous carbon nanocomposites with tunable mesopore sizes below 850 °C without using graphitization catalysts or high temperature thermal treatments. Phenolic resin-based mesoporous carbons act as mortar to highly conductive carbon blacks and carbon onions (bricks). The capacitance and resistivity of final materials can be tailored by changing the mortar to brick ratios.

  18. Synthesis of highly-ordered mesoporous carbon/silica nanocomposites and derivative hierarchically mesoporous carbon from a phenyl-bridged organosiloxane

    NASA Astrophysics Data System (ADS)

    Wu, Zhiwang; Pang, Jiebin; Lu, Yunfeng

    2009-11-01

    Mesoporous carbon/silica nanocomposites and derivative hierarchically mesoporous carbon have been prepared using 1,4-bis(triethoxysilyl)benzene (BTEB) as a precursor for a carbon/silica network and Pluronic P123 (HO(CH2CH2O)20(CH2CH(CH3)O)70(CH2CH2O)20H) as a template for highly-ordered hexagonal pores. Co-assembly of BTEB and P123 and subsequent carbonization results in a mesoporous carbon/silica nanocomposite with hexagonally oriented pores. Removal of the silica component in the carbon/silica network creates a second porosity in the network and results in hierarchically mesoporous carbon. The mesostructure of these materials was characterized by transmission electron microscopy (TEM), field-emission scanning electron microscopy (FE-SEM), powder X-ray diffraction (PXRD), and N2 sorption.

  19. The effects of ageing time on the microstructure and properties of mesoporous silica-hydroxyapatite nanocomposite

    NASA Astrophysics Data System (ADS)

    Yousefpour, Mardali; Taherian, Zahra

    2013-02-01

    In this study, a mesoporous silica-hydroxyapatite nanocomposite (MCM-41/HA) was synthesized via sol-gel technique as a drug delivery system. The synthesis of MCM-41/hydroxyapatite nanocomposite was carried out at room temperature. The effect of various ageing time on the nanocomposite properties was studied during synthesis process. 0, 24, 36, and 48 h aging times were chosen. Textural properties and microstructure of the nanocomposites were characterized by X-ray diffraction (XRD), Transmission Electron Microscopy (TEM), Energy Dispersive X-ray Spectroscopy (EDS), Electron Diffraction pattern (ED), and N2 adsorption-desorption. Results showed that ageing process led to HA crystals nucleation and growth on the surface of mesoporous silica. At 48 h of aging time, the surface area and total pore volume increased from 36.2 to 334 m2/g and 0.14-0.7 cm3/g, respectively. In contrast, the average pore diameter considerably decreased from 20.1 nm for (MCM-41/HA)24 to 8.39 nm for (MCM-41/HA)48. Furthermore, it was observed more homogeneous pore distribution with increasing the ageing time. In conclusion, the ageing time play an important role on textural properties of MCM-41/HA nanocomposite which could have a major effect on drug delivery properties such as molecular loading and release kinetics.

  20. Controlled Cell Growth and Cell Migration in Periodic Mesoporous Organosilica/Alginate Nanocomposite Hydrogels.

    PubMed

    Seda Kehr, Nermin; Riehemann, Kristina

    2016-01-21

    Nanocomposite (NC) hydrogels with different periodic mesoporous organosilica (PMO) concentrations and a NC hydrogel bilayer with various PMO concentrations inside the layers of the hydrogel matrix are prepared. The effect of the PMO concentration on cell growth and migration of cells is reported. The cells migrate in the bilayer NC hydrogel towards higher PMO concentrations and from cell culture plates to NC hydrogel scaffolds. PMID:26648333

  1. Synthesis of mesoporous nanocomposites for their application in solid oxide electrolysers cells: microstructural and electrochemical characterization.

    PubMed

    Torrell, M; Almar, L; Morata, A; Tarancón, A

    2015-01-01

    Fabrication routes for new SOEC mesoporous nanocomposite materials as electrodes are presented in this paper. NiO-CGO and SDC-SSC are described as possible new materials and their synthesis and the cell fabrication are discussed. The obtained materials are microstructurally characterised by SEM, TEM and XRD, where the mesoporous structures are observed and analysed. The obtained samples are electrochemically analysed by I-V polarisation curves and EIS analysis, showing a maximum current density of 330 mA cm(-2) at 1.7 V. A degradation of the cell performance is evidenced after a potentiostatic test at 1.4 V after more than 40 hours. Oxygen electrode delaminating is detected, which is most probably the main cause of ageing. Even taking into account the lack of durability of the fabricated cells, the mesoporous electrodes do not seem to be altered, opening the possibility for further studies devoted to this high stability material for SOEC electrodes. PMID:26212761

  2. Amine-Impregnated Mesoporous Silica Nanotube as an Emerging Nanocomposite for CO2 Capture.

    PubMed

    Niu, Mengya; Yang, Huaming; Zhang, Xiangchao; Wang, Yutang; Tang, Aidong

    2016-07-13

    Pristine halloysite nanotubes (HNTs) were pretreated to produce mesoporous silica nanotubes (MSiNTs), which was further impregnated with polyethenimine (PEI) to prepare an emerging nanocomposite MSiNTs/PEI (MP) for CO2 capture. Thermogravimetric analysis (TGA) was employed to analyze the influences of PEI loading amount and adsorption temperature on CO2 adsorption capacity of the nanocomposite. The Brunauer-Emmett-Teller (BET) surface area (SBET) of MSiNTs was six times higher than that of HNTs, and the corresponding pore volume was more than two times higher than that of HNTs. The well dispersion of PEI within the nanotubes of MSiNTs benefits more CO2 gas adsorption, and the adsorption capacity of the nanocomposite could reach 2.75 mmol/g at 85 °C for 2 h. The CO2 adsorption on the nanocomposite was demonstrated to occur via a two-stage process: initially, a sharp linear weight increase at the beginning, and then a relatively slow adsorption step. The adsorption capacity could reach as high as 70% within 2 min. Also, the nanocomposite exhibited good stability on CO2 adsorption/desorption performance, indicating that the as-prepared emerging nanocomposite show an interesting application potential in the field of CO2 capture. PMID:27315143

  3. One-step synthesis of degradable T1-FeOOH functionalized hollow mesoporous silica nanocomposites from mesoporous silica spheres

    NASA Astrophysics Data System (ADS)

    Peng, Yung-Kang; Tseng, Yu-Jui; Liu, Chien-Liang; Chou, Shang-Wei; Chen, Yu-Wei; Tsang, S. C. Edman; Chou, Pi-Tai

    2015-01-01

    The combination of a hollow mesoporous structure and a magnetic resonance (MR) contrast agent has shown its potential in simultaneous drug delivery and cell tracking applications. However, the preparation of this kind of nanocomposite is complicated and usually takes several days, which is unsuitable for scaled-up production. To overcome these hurdles, we report herein a facile method to synthesize iron oxide hydroxide functionalized hollow mesoporous silica spheres (FeOOH/HMSS) in a one-step manner. By carefully controlling the reaction kinetics of K2FeO4 in water, the gram-scale production of FeOOH/HMSS can be readily achieved at 60 °C for as short as 30 min. Most importantly, this synthetic process is also cost-effective and eco-friendly in both the precursor (K2FeO4 and H2O) and the product (FeOOH). The mechanism for the formation of a hollow structure was carefully investigated, which involves the synergetic effect of the surfactant CTAB and the side product KOH. Having outstanding biocompatibility, these degradable nanocolloids also demonstrate their feasibility in in vitro/vivo MR imaging and in vitro drug delivery.The combination of a hollow mesoporous structure and a magnetic resonance (MR) contrast agent has shown its potential in simultaneous drug delivery and cell tracking applications. However, the preparation of this kind of nanocomposite is complicated and usually takes several days, which is unsuitable for scaled-up production. To overcome these hurdles, we report herein a facile method to synthesize iron oxide hydroxide functionalized hollow mesoporous silica spheres (FeOOH/HMSS) in a one-step manner. By carefully controlling the reaction kinetics of K2FeO4 in water, the gram-scale production of FeOOH/HMSS can be readily achieved at 60 °C for as short as 30 min. Most importantly, this synthetic process is also cost-effective and eco-friendly in both the precursor (K2FeO4 and H2O) and the product (FeOOH). The mechanism for the formation of a

  4. A facile synthesis of mesoporous Pdsbnd ZnO nanocomposites as efficient chemical sensor

    NASA Astrophysics Data System (ADS)

    Ismail, Adel A.; Harraz, Farid A.; Faisal, M.; El-Toni, Ahmed Mohamed; Al-Hajry, A.; Al-Assiri, M. S.

    2016-07-01

    Mesoporous ZnO was synthesized through the sol-gel method in the presence of triblock co-polymer Pluronic (F-127) template as the structure directing agent. Palladium nanoparticles were photochemically reduced and deposited onto mesoporous ZnO to obtain 1 wt.% Pd/ZnO nanocomposite. Structural and morphological analysis revealed high homogeneity and monodispersity of Pd nanoclusters with small particle sizes ∼ 2-5 nm onto mesoporous ZnO. The electrochemical detection of ethanol in aqueous solutions was conducted at the newly developed Pd/ZnO modified glassy carbon electrode (GCE) by the current-potential (IV) and cyclic voltammetry (CV) techniques and compared with bare GCE or pure ZnO. The presence of Pd dopant greatly enhances the sensitivity of ZnO, and the obtained mesoporous Pd/ZnO sensor has an excellent performance for precision detection of ethanol in aqueous solution with low concentration. The sensitivity was found to be 33.08 μAcm-2 mM-1 at lower concentration zone (0.05-0.8 mM) and 2.13 μAcm-2 mM-1 at higher concentration zone (0.8-12 mM), with a limit of detection (LOD) 19.2 μM. The kinetics study of ethanol oxidation revealed a characteristic feature for a mixed surface and diffusion-controlled process. These excellent sensing characteristics make the mesoporous Pd/ZnO nanocomposite a good candidate for the production of high-performance electrochemical sensors at low ethanol concentration in aqueous solution.

  5. Synthesis of mesoporous sulfur-doped Ta2O5 nanocomposites and their photocatalytic activities.

    PubMed

    Ismail, Adel A; Faisal, M; Harraz, Farid A; Al-Hajry, A; Al-Sehemi, A G

    2016-06-01

    Mesoporous sulfur (S)-doped Ta2O5 nanocomposites have been synthesized for the first time through the sol-gel reaction of tantalum chloride and thiourea in the presence of a F127 triblock copolymer as structure directing agent. The as-formed mesophase S-doped Ta2O5 hybrid gels were calcined at 700°C for 4h to obtain mesoporous S-Ta2O5 nanocomposites. The experimental results indicated that the surface area of the S-doped Ta2O5 was up to 50m(2)g(-1) and the pore diameter was controllable in the range of 3-7.7nm. The S-doped Ta2O5 nanocomposites behave as superior visible light-sensitive photocatalysts and the 1.5at.% S-doped Ta2O5 (S1.5) photocatalyst exhibited excellent photocatalytic activity of ∼92% for the photodegradation of methylene blue, identical to 80% TOC removal after three hours illumination under visible light. The photodegradation rate of S1.5 photocatalyst showed 3.4 times higher than the undoped Ta2O5 due to their narrow bandgap, large surface area, mesostructure and well crystalline state. The S1.5 photocatalyst could be recycled at least five times without an apparent decrease in its photocatalytic efficiency, indicating its high stability for practical applications. To the best of our knowledge, this is the first report that demonstrates one-step synthesis of mesoporous S-doped Ta2O5 nanocomposites as an efficient photocatalysts under visible light illumination. PMID:27017474

  6. Synthesis of white light emitting mesoporous carbon-silica nanocomposite

    NASA Astrophysics Data System (ADS)

    Sato, Koji; Ishikawa, Yukari; Matsumura, Akihiro; Ishii, Yosuke; Kawasaki, Shinji

    2011-05-01

    White light emitting mesoporous carbon-silica (MPCS) was synthesized by serially adding triblock copolymer (Pluronic, F127), ethanol (EtOH), tetraethoxysilane (TEOS), hydrochloric acid aqueous (HCl) and phenol-formaldehyde resin (resol) followed by the heat treatments of carbonization and oxidation. The PL intensity of MPCS showed a tendency to be strong with increasing of HCl concentration in >= 0.2 M. The pore size of MPCS that emits white light was 8 ~ 9 nm and the specific surface area was 320 ~ 418 m2 / g.

  7. Core-shell-type magnetic mesoporous silica nanocomposites for bioimaging and therapeutic agent delivery.

    PubMed

    Wang, Yao; Gu, Hongchen

    2015-01-21

    Advances in nanotechnology and nanomedicine offer great opportunities for the development of nanoscaled theranostic platforms. Among various multifunctional nanocarriers, magnetic mesoporous silica nanocomposites (M-MSNs) attract prominent research interest for their outstanding properties and potential biomedical applications. This Research News article highlights recent progress in the design of core-shell-type M-MSNs for both diagnostic and therapeutic applications. First, an overview of synthetic strategies for three representative core-shell-type M-MSNs with different morphologies and structures is presented. Then, the diagnostic functions of M-MSNs is illustrated for magnetic resonance imaging (MRI) applications. Next, magnetic targeted delivery and stimuli-responsive release of drugs, and effective package of DNA/siRNA inside mesopores using M-MSNs as therapeutic agent carriers are discussed. The article concludes with some important challenges that need to be overcome for further practical applications of M-MSNs in nanomedicine. PMID:25238634

  8. Bottom-up assembly of hydrophobic nanocrystals and graphene nanosheets into mesoporous nanocomposites.

    PubMed

    Huang, Jijiang; Liu, Wenxian; Wang, Li; Sun, Xiaoming; Huo, Fengwei; Liu, Junfeng

    2014-04-22

    A general strategy for constructing graphene-based nanocomposites is achieved by emulsion-based bottom-up self-assembly of hydrophobic nanocrystals (NCs) to positively charged colloidal spheres, followed by the electrostatic assembly of NC colloidal spheres with negatively charged graphene oxide in an acidulous aqueous solution. With a simple heat treatment, 3D mesoporous NC spheres/graphene composites are obtained. TiO2/graphene composites typically exhibit a better rate capability and cycle performance than do the corresponding isolated TiO2 spheres. PMID:24684553

  9. Facile fabrication of mesoporous iron modified Al2O3 nanoparticles pillared montmorillonite nanocomposite: a smart photo-Fenton catalyst for quick removal of organic dyes.

    PubMed

    Pradhan, Amaresh C; Varadwaj, G Bishwa Bidita; Parida, K M

    2013-11-14

    A mesoporous iron modified Al2O3 nanoparticle pillared montmorillonite nanocomposite (mesoporous Fe/APM nanocomposite) was synthesized by using sodium exchanged montmorillonite by cation-exchange, gallery-templated synthesis and impregnation method. Formation of Al2O3 nanoparticles (Al2O3 NPs) having average particle size 5.20-6.50 nm within montmorillonite, formation of mesoporous Al2O3 NPs pillared montmorillonite (mesoporous APM) from montmorillonite and formation of a mesoporous Fe/APM nanocomposite signifies the present investigation. The roles of ammonia, CTAB, octyl amine and calcination temperature for fabrication of mesoporous Fe/APM nanocomposite were highly significant. Ammonia was used for post-synthesis treatment, which helped in the formation of micellar assemblies in the interlayer space. The materials were characterized by different techniques such as N2 adsorption-desorption study, which demonstrated the mesoporosity of the material. A transmission electron microscopy (TEM) image proves the morphology and size of the Al2O3 NPs and mesoporous Fe/APM nanocomposites. X-ray diffraction technique (XRD) describes the formation of the pillaring of the Al2O3 NPs within montmorillonite (APM). It has been noted that pure montmorillonite is a micro/mesoporous material. But after pillaring of Al2O3 NPs within the montmorillonite, mesoporosity developed, which is the vital aspect of present investigation. It was observed that the mesoporous Fe/APM nanocomposite has high photo-Fenton activity towards degradation of organic dyes such as acid blue (AB) and reactive blue (RB). Nearly 100% degradation took place within 30 minutes with high concentration of dye (500 mg L(-1)) by mesoporous 5 Fe/APM nanocomposite under ambient conditions. Small particle sizes of nanocomposite, quick reduction of Fe(III) and mesoporosity are the key points for proficient degradation of AB and RB. PMID:24002045

  10. Synthesis and characterization of magnetic iron oxide/calcium silicate mesoporous nanocomposites as a promising vehicle for drug delivery.

    PubMed

    Lu, Bing-Qiang; Zhu, Ying-Jie; Ao, Hai-Yong; Qi, Chao; Chen, Feng

    2012-12-01

    The synthesis of the mesoporous nanocomposites consisting of magnetic iron oxide nanoparticles and calcium silicate with uniform size has been a challenge, although they are the ideal potential agent for medical diagnosis and therapy. In this work, the core/shell structured mesoporous nanocomposites consisting of magnetic iron oxide nanoparticles as the core and calcium silicate as the shell have been successfully synthesized using a two liquid phase system by ultrasound irradiation, in which the hydrophobic phase is composed of hydrophobic Fe(3)O(4) nanoparticles and tetraethyl orthosilicate (TEOS), and the water phase consists of Ca(NO(3))(2), NaOH, and water. The hollow mesoporous nanocomposites consisting of magnetic iron oxide nanoparticles and calcium silicate are obtained by adding a certain amount of the inert hydrophobic solvent isooctane in the reaction system before ultrasound irradiation. The nanocomposites have a superparamagnetic behavior, high Brunauer-Emmett-Teller (BET) specific surface area (474 m(2) g(-1)), and high Barrett-Joyner-Halenda (BJH) pore volume (2.75 cm(3) g(-1)). The nanocomposites have high drug loading capacities for bovine hemoglobin, docetaxel, and ibuprofen. The docetaxel-loaded nanocomposites have the anticancer ability and, thus, are promising for applications in biomedical fields. PMID:23210766

  11. Effects of Synthesis Process on Luminescence Properties and Structure of Mesoporous Carbon-Silica Nanocomposite

    NASA Astrophysics Data System (ADS)

    Sato, Koji; Ishikawa, Yukari; Ishii, Yosuke; Kawasaki, Shinji; Muto, Shunsuke; Yamamoto, Yuta

    2012-08-01

    The effects of hydrolysis and polycondensation reactions for synthesizing light-emitting mesoporous carbon-silica (MPCS) nanocomposite on the structure, chemical bonding state, and luminescence properties of MPCS were investigated by controlling the concentration (0.02 to 5 M) of HCl, which was used as a catalyst for hydrolysis and polycondensation. The progress of hydrolysis and polycondensation reactions provides a nanometer-order pore/wall structure and results in a strong light-emitting property. The pore/wall structure was obtained using HCl at concentrations of 0.2 M and higher, but it became disordered with increasing HCl concentration (2 and 5 M). The luminescence color of the MPCS nanocomposite can be changed from yellowish-white to bluish-white by changing the concentration of HCl.

  12. A mesoporous silica nanocomposite shuttle: pH-triggered phase transfer between oil and water.

    PubMed

    Wang, Haixia; Yang, Hengquan; Liu, Huanrong; Yu, Yuhong; Xin, Hongchuan

    2013-06-01

    With a simple protocol, we synthesize a novel mesoporous silica nanocomposite shuttle that can reversibly transfer between an organic phase and water in response to the pH, due to the switchable surface hydrophobicity/hydrophilicity. Our synthesis protocol allows the phase transfer ability to be tuned in a controllable fashion. This nanocomposite shuttle exhibits a good ability to load various cargoes such as Pd(OAc)2, Pd nanoparticles, and organic molecules. The built-in properties of the nanocomposite shuttle lay the foundations for many innovative applications. As a proof of concept, we successfully demonstrate its application in separating and recycling Pd nanoparticle catalysts. The composite shuttle can take Pd nanoparticles to an organic phase for catalyzing hydrogenation of olefins and come back to an aqueous phase at the end of reaction, making in situ separation and recycling of nanocatalysts possible. This pH-driven round trip for catalysis can be repeated several times. Our investigations not only supply a novel nanocomposite shuttle with controllable properties but also open an innovative avenue to in situ separation and recycling of nanocatalysts, which can address the obstacles of the conventional methods such as centrifugation and filtration. PMID:23509875

  13. Microwave absorption properties and infrared emissivities of ordered mesoporous C-TiO{sub 2} nanocomposites with crystalline framework

    SciTech Connect

    Wang, Tao; He, Jianping; Zhou, Jianhua; Tang, Jing; Guo, Yunxia; Ding, Xiaochun; Wu, Shichao; Zhao, Jianqing

    2010-12-15

    Ordered mesoporous C-TiO{sub 2} nanocomposites with crystalline framework were prepared by the evaporation-induced triconstituent co-assembly method. The products were characterized by XRD, TEM, N{sub 2} adsorption-desorption and TG. Their microwave absorption properties were investigated by mixing the product and epoxy resin. It is found that the peak with minimum reflection loss value moves to lower frequencies and the ordered mesoporous C-TiO{sub 2} nanocomposite possesses an excellent microwave absorbing property with the maximum reflection loss of -25.4 dB and the bandwidth lower than -10 dB is 6.6 GHz. The attenuation of microwave can be attributed to dielectric loss and their absorption mechanism is discussed in detail. The mesoporous C-TiO{sub 2} nanocomposites also exhibit a lower infrared emissivity in the wavelength from 8 to 14 {mu}m than that of TiO{sub 2}-free powder. -- Graphical abstract: Ordered mesoporous C-TiO{sub 2} nanocomposite with crystalline framework possess excellent microwave absorbing properties with the maximum reflection loss of -25.4 dB and the bandwidth lower than -10 dB is 6.6 GHz. Display Omitted

  14. Graphene-mediated surface enhanced Raman scattering in silica mesoporous nanocomposite films.

    PubMed

    Carboni, Davide; Lasio, Barbara; Alzari, Valeria; Mariani, Alberto; Loche, Danilo; Casula, Maria F; Malfatti, Luca; Innocenzi, Plinio

    2014-12-21

    Silica mesoporous nanocomposite films containing graphene nanosheets and gold nanoparticles have been prepared via a one-pot synthesis using silicon tetrachloride, gold(III) chloride tetrahydrate, a 1-N-vinyl-2-pyrrolidone dispersion of exfoliated graphene and Pluronic F127 as a structuring agent. The composite films have shown graphene-mediated surface-enhanced Raman scattering (G-SERS). Graphene has been introduced as dispersed bilayer sheets while gold has been thermally reduced in situ to form nanoparticles of around 6 nm which preferentially nucleate on the surface of the graphene nanosheets. The presence of graphene and gold nanoparticles does not interfere with the self-assembly process and the formation of silica mesoporous films ordered as 2D hexagonal structures. The material has shown a remarkable analytical enhancement factor ranging from 80 up to 136 using rhodamine 6G as a Raman probe. The films have been characterised by grazing incidence X-ray diffraction, FTIR and UV-vis spectroscopy studies; transmission electron microscopy and spectroscopic ellipsometry have been used to study the morphology, thickness and porosities of the samples. Raman spectroscopy has been employed to characterise the graphene nanosheets embedded into the mesoporous films and the enhanced Raman scattering. PMID:25278085

  15. Nanocomposite hydrogels for cartilage tissue engineering: mesoporous silica nanofibers interlinked with siloxane derived polysaccharide.

    PubMed

    Buchtová, Nela; Réthoré, Gildas; Boyer, Cécile; Guicheux, Jérôme; Rambaud, Frédéric; Vallé, Karine; Belleville, Philippe; Sanchez, Clément; Chauvet, Olivier; Weiss, Pierre; Le Bideau, Jean

    2013-08-01

    Injectable materials for mini-invasive surgery of cartilage are synthesized and thoroughly studied. The concept of these hybrid materials is based on providing high enough mechanical performances along with a good medium for chondrocytes proliferation. The unusual nanocomposite hydrogels presented herein are based on siloxane derived hydroxypropylmethylcellulose (Si-HPMC) interlinked with mesoporous silica nanofibers. The mandatory homogeneity of the nanocomposites is checked by fluorescent methods, which show that the silica nanofibres dispersion is realized down to nanometric scale, suggesting an efficient immobilization of the silica nanofibres onto the Si-HPMC scaffold. Such dispersion and immobilization are reached thanks to the chemical affinity between the hydrophilic silica nanofibers and the pendant silanolate groups of the Si-HPMC chains. Tuning the amount of nanocharges allows tuning the resulting mechanical features of these injectable biocompatible hybrid hydrogels. hASC stem cells and SW1353 chondrocytic cells viability is checked within the nanocomposite hydrogels up to 3 wt% of silica nanofibers. PMID:23666665

  16. Multifunctional Gold-Mesoporous Silica Nanocomposites for Enhanced Two-Photon Imaging and Therapy of Cancer Cells

    PubMed Central

    Croissant, Jonas G.; Qi, Christian; Maynadier, Marie; Cattoën, Xavier; Wong Chi Man, Michel; Raehm, Laurence; Mongin, Olivier; Blanchard-Desce, Mireille; Garcia, Marcel; Gary-Bobo, Magali; Durand, Jean-Olivier

    2016-01-01

    Three dimensional sub-micron resolution has made two-photon nanomedicine a very promising medical tool for cancer treatment since current techniques cause significant side effects for lack of spatial selectivity. Two-photon-excited (TPE) photodynamic therapy (PDT) has been achieved via mesoporous nanoscaffolds, but the efficiency of the treatment could still be improved. Herein, we demonstrate the enhancement of the treatment efficiency via gold-mesoporous organosilica nanocomposites for TPE-PDT in cancer cells when compared to mesoporous organosilica particles. We performed the first comparative study of the influence of the shape and spatial position of gold nanoparticles (AuNPs) with mesoporous silica nanoparticles (MSN) functionalized with thiol groups and doped with a two-photon electron donor (2PS). The resulting multifunctional nanocarriers displayed TPE-fluorescence and were imaged inside cells. Furthermore, mesoporous organosilica NPs decorated gold nanospheres (AuNSs) induced 63 percent of selective killing on MCF-7 breast cancer cells. This study thus provides insights for the design of more effective multifunctional two-photon-sensitive nanocomposites via AuNPs for biomedical applications. PMID:26870736

  17. Fabrication and characterization of mesoporous TiO{sub 2}/polypyrrole-based nanocomposite for electrorheological fluid

    SciTech Connect

    Wei Chuan; Zhu Yihua Jin Yi; Yang Xiaoling; Li Chunzhong

    2008-12-01

    Mesoporous TiO{sub 2}/polypyrrole (PPy)-based nanocomposite for electrorheological fluid was synthesized through one-pot method. By exploiting the combination conductivity of PPy and high dielectric constant of TiO{sub 2}, the ER fluid exhibited an enhanced effect. The shear stress was 3.3 times as high as that of mesoporous TiO{sub 2}. Powder X-ray diffraction (XRD), TEM and Fourier transform infrared (FT-IR) spectroscopy were employed to characterize the as-made samples. Using a modified rotational viscometer, the electrorheological effect was measured. Dielectric spectra were also given to explain the mechanism.

  18. The plumber's nightmare: a new morphology in block copolymer-ceramic nanocomposites and mesoporous aluminosilicates.

    PubMed

    Finnefrock, Adam C; Ulrich, Ralph; Toombes, Gilman E S; Gruner, Sol M; Wiesner, Ulrich

    2003-10-29

    A novel cubic bicontinuous morphology is found in polymer-ceramic nanocomposites and mesoporous aluminosilicates that are derived by an amphiphilic diblock copolymer, poly(isoprene-b-ethylene oxide) (PI-b-PEO), used as a structure-directing agent for an inorganic aluminosilicate. Small-angle X-ray scattering (SAXS) was employed to unambiguously identify the Im(-)3m crystallographic symmetry of the materials by fitting individual Bragg peak positions in the two-dimensional X-ray images. Structure factor calculations, in conjunction with results from transmission electron microscopy, were used to narrow the range of possible structures consistent with the symmetry and showed the plumber's nightmare morphology to be consistent with the data. The samples are made by deposition onto a substrate that imposes a strain field, generating a lattice distortion. This distortion is quantitatively analyzed and shown to have resulted in shrinkage of the crystallites by approximately one-third in a direction perpendicular to the substrate, in both as-made composites and calcined ceramic materials. Finally, the observation of the bicontinuous block-copolymer-derived hybrid morphology is discussed in the context of a pseudo-ternary morphology diagram and compared to existing studies of ternary phase diagrams of amphiphiles in a mixture of two solvents. The calcined mesoporous materials have potential applications in the fields of catalysis, separation technology, and microelectronics. PMID:14570481

  19. Enantiomorphous Periodic Mesoporous Organosilica-Based Nanocomposite Hydrogel Scaffolds for Cell Adhesion and Cell Enrichment.

    PubMed

    Kehr, Nermin Seda

    2016-03-14

    The chemical functionalization of nanomaterials with bioactive molecules has been used as an effective tool to mimic extracellular matrix (ECM) and to study the cell-material interaction in tissue engineering applications. In this respect, this study demonstrates the use of enantiomerically functionalized periodic mesoporous organosilicas (PMO) for the generation of new multifunctional 3D nanocomposite (NC) hydrogels to control the affinity of cells to the hydrogel surfaces and so to control the enrichment of cells and simultaneous drug delivery in 3D network. The functionalization of PMO with enantiomers of bioactive molecules, preparation of their nanocomposite hydrogels, and the stereoselective interaction of them with selected cell types are described. The results show that the affinity of cells to the respective NC hydrogel scaffolds is affected by the nature of the biomolecule and its enantiomers, which is more pronounced in serum containing media. The differentiation of enantiomorphous NC hydrogels by cells is used to enrich one cell type from a mixture of two cells. Finally, PMO are utilized as nanocontainers to release two different dye molecules as a proof of principle for multidrug delivery in 3D NC hydrogel scaffolds. PMID:26811946

  20. Mesoporous Hybrid Polypyrrole-Silica Nanocomposite Films with a Strata-Like Structure.

    PubMed

    Farghaly, Ahmed A; Collinson, Maryanne M

    2016-06-14

    Using a single-potential-step coelectrodeposition route, Ppy-SiO2 nanocomposite films characterized by a multimodal porous structure were cathodically deposited from ethanolic solutions on oxidizable and nonoxidizable substrates for the first time. The materials produced have an interesting and unique strata-like pore structure along their depth. With the exception of a silica-rich inner region, the nanocomposite films are homogeneous in composition. Because the region closest to the electrode surface is silica-rich, the fabrication of Ppy-SiO2 and Ppy free-standing films become possible using a multistep etching strategy. Such films can be captured on a variety of different supports depending on the application, and they maintain their conductivity when interfaced with an electrode surface. These mesoporous composite films form through a unique mechanism that involves the production of two catalysts, OH(-) and NO(+). Through the process of understanding the reaction mechanism, we highlighted the effect of two simultaneous competing redox reactions occurring at the electrode interface on the morphology of the electrodeposited Ppy nanocomposite films and how solvent can influence the Ppy electropolymerization reaction mechanism and hence control the morphology of the final material. In an ethanolic solvent system, the pyrrole monomers undergo a step-growth polymerization, and particulate-like nanostructured films were obtained even upon changing the monomer or acid concentration. In an aqueous-based system, nanowire-like structures were produced, which is consistent with a chain-growth mechanism. Such materials are promising candidates for a wide range of applications including electrochemical sensing, energy storage, and catalysis. PMID:27245273

  1. Amperometric hydrogen peroxide and glucose biosensor based on NiFe2/ordered mesoporous carbon nanocomposites.

    PubMed

    Xiang, Dong; Yin, Longwei; Ma, Jingyun; Guo, Enyan; Li, Qun; Li, Zhaoqiang; Liu, Kegao

    2015-01-21

    Nanocomposites of NiFex embedded in ordered mesoporous carbon (OMC) (x = 0, 1, 2) were prepared by a wet impregnation and hydrogen reduction process and were used to construct electrochemical biosensors for the amperometric detection of hydrogen peroxide (H2O2) or glucose. The NiFe2/OMC nanocomposites were demonstrated to have a large surface area, suitable mesoporous channels, many edge-plane-like defective sites, and a good distribution of alloyed nanoparticles. The NiFe2/OMC and Nafion modified glass carbon electrode (GCE) exhibited excellent electrocatalytic activities toward the reduction of H2O2 as well. By utilizing it as a bioplatform, GOx (glucose oxidase) cross-linked with Nafion was immobilized on the surface of the electrode for the construction of an amperometric glucose biosensor. Our results indicated that the amperometric hydrogen peroxide biosensor (NiFe2/OMC + Nafion + GCE) showed good analytical performances in term of a high sensitivity of 4.29 μA mM(-1) cm(-2), wide linearity from 6.2 to 42,710 μM and a low detection limit of 0.24 μM at a signal-to-noise ratio of 3 (S/N = 3). This biosensor exhibited excellent selectivity, high stability and negligible interference for the detection of H2O2. In addition, the immobilized enzyme on NiFe2/OMC + Nafion + GCE, retaining its bioactivity, exhibited a reversible two-proton and two-electron transfer reaction, a fast heterogeneous electron transfer rate and an effective Michaelis-Menten constant (K) (3.18 mM). The GOx + NiFe2/OMC + Nafion + GCE could be used to detect glucose based on the oxidation of glucose catalyzed by GOx and exhibited a wide detection range of 48.6-12,500 μM with a high sensitivity of 6.9 μA mM(-1) cm(-2) and a low detection limit of 2.7 μM (S/N = 3). The enzymic biosensor maintained a high selectivity and stability features, and shows great promise for application in the detection of glucose. PMID:25429370

  2. Multifunctional magnetic mesoporous silica nanocomposites with improved sensing performance and effective removal ability toward Hg(II).

    PubMed

    Wang, Yanyan; Li, Bin; Zhang, Liming; Li, Peng; Wang, Lianlian; Zhang, Jin

    2012-01-17

    In the present work, a multifunctional inorganic-organic hybrid nanomaterial (MMS-Py) was prepared by the immobilization of a pyrene-based receptor (Py) within the channels of magnetic mesoporous silica nanocomposites (MMS), and characterized by scanning electron microscopy, transmission electron microscopy, Fourier transform infrared spectroscopy, X-ray diffraction, N(2) adsorption/desorption, superconducting quantum interference device, and photoluminescence spectra. This multifunctional nanomaterial exhibits superparamagnetic behavior, ordered mesoporous characteristics, and significantly improved fluorescence sensing properties that allow for highly sensitive and reproducible Hg(2+) detection. The fluorogenical responses of MMS-Py are stable over a broad pH range. A detection limit of 1.72 ppb is obtained, which is 2 orders of magnitude lower than that based on bulk mesoporous materials. Additionally, this nanomaterial shows high performance in convenient magnetic separability and efficient removal of Hg(2+). These results indicate that these multifunctional nanocomposites may find potential applications for simple detection and easy removal of Hg(2+) in biological, toxicological, and environmental areas. PMID:22185678

  3. Study of interface interactions in ZnO/Mesoporous silica nanocomposite

    NASA Astrophysics Data System (ADS)

    Reddy A, R. C.; Babu K, Sowri; Ch, Sujatha; Reddy K, V. G.

    2012-02-01

    The Photoluminescence (PL) properties of ZnO/Mesoporous silica (MPS) nanocomposite annealed under different temperatures were studied. A broad PL band at 395 nm has been observed in all samples and analysis was made by using Gaussian fitting. As the temperature increased, emission bands were blue shifted and the relative intensity ratio of the oxygen vacancies at ZnO-SiO2 interface to the oxygen vacancies in inner ZnO crystallites was increased. The emission peaks at 363 nm and 384 nm are attributed to the near band edge emission (NBE) and to the phonon replica emission. At 550C the exciton confinement effect disappears due to the large amount of surface effects. The influence of porosity of host media on Si-O-Zn cross linking bonds was also investigated. ZnO nanoparticles were loaded into nanocrystalline silica (NCS) and silica gel (SG). The surface area increases monotonously from NCS to MPS through SG. Si-O-Zn cross linking bonds were almost absent in the sample prepared with NCS. It exhibits NBE emission at 360 nm which was found to be absent in other samples prepared with SG and MPS. It was also found that the emission intensity of the samples decreases with aging. This is due to diffusion of oxygen atoms from the atmosphere to interior of the sample.

  4. Triconstituent co-assembly to ordered mesostructured polymer-silica and carbon-silica nanocomposites and large-pore mesoporous carbons with high surface areas.

    PubMed

    Liu, Ruili; Shi, Yifeng; Wan, Ying; Meng, Yan; Zhang, Fuqiang; Gu, Dong; Chen, Zhenxia; Tu, Bo; Zhao, Dongyuan

    2006-09-01

    Highly ordered mesoporous polymer-silica and carbon-silica nanocomposites with interpenetrating networks have been successfully synthesized by the evaporation-induced triconstituent co-assembly method, wherein soluble resol polymer is used as an organic precursor, prehydrolyzed TEOS is used as an inorganic precursor, and triblock copolymer F127 is used as a template. It is proposed for the first time that ordered mesoporous nanocomposites have "reinforced concrete"-structured frameworks. By adjusting the initial mass ratios of TEOS to resol, we determined the obtained nanocomposites possess continuous composition with the ratios ranging from zero to infinity for the two constituents that are "homogeneously" dispersed inside the pore walls. The presence of silicates in nanocomposites dramatically inhibits framework shrinkage during the calcination, resulting in highly ordered large-pore mesoporous carbon-silica nanocomposites. Combustion in air or etching in HF solution can remove carbon or silica from the carbon-silica nanocomposites and yield ordered mesoporous pure silica or carbon frameworks. The process generates plenty of small pores in carbon or/and silica pore walls. Ordered mesoporous carbons can then be obtained with large pore sizes of approximately 6.7 nm, pore volumes of approximately 2.0 cm(3)/g, and high surface areas of approximately 2470 m(2)/g. The pore structures and textures can be controlled by varying the sizes and polymerization degrees of two constituent precursors. Accordingly, by simply tuning the aging time of TEOS, ordered mesoporous carbons with evident bimodal pores at 2.6 and 5.8 nm can be synthesized. PMID:16939291

  5. Multiple constituents co-assembly of ordered mesoporous Al2O3-SiO2-carbon nanocomposites.

    PubMed

    Wang, Wei; Xue, Huanhuan; Feng, Cuimiao; Kong, Lina; Zhao, Qingfei; Wan, Ying

    2013-02-01

    Ordered mesoporous Al2O3-SiO2-carbon nanocomposites have been synthesized via the direct triblock-copolymer self-assembly route using soluble phenolic resols as polymer precursors, aluminium chloride hexahydrate as an aluminum precursor, tetraethoxysilane as a silica precursor, and Pluronic F127 as a template. Characterization of XRD, N2 sorption isotherms, TEM, solid-state NMR, TG, and NH3-TPD techniques is used to investigate the mesostructure, pore properties, phase composition, metal incorporation state, and acidic properties. Ordered mesoporous nanocomposites have "reinforced concrete"-structured frameworks, in which the oxide and carbon components are microphase separated and homogenously dispersed inside pore walls. Al species are tetrahedrally incorporated into silica frameworks to compose the inorganic oxide compounds which provides acidic center. The nanocomposites have the ordered 2-D hexagonal mesostructure, high surface areas (291-360 m2/g), large pore volumes (0.25-0.42 cm3/g), large pore diameters (- 5 nm) and accessible acidic sites. PMID:23646686

  6. Designed synthesis of aptamer-immobilized magnetic mesoporous silica/Au nanocomposites for highly selective enrichment and detection of insulin.

    PubMed

    Xiong, Ya; Deng, Chunhui; Zhang, Xiangmin; Yang, Pengyuan

    2015-04-29

    We designed and synthesized aptamer-immobilized magnetic mesoporous silica/Au nanocomposites (MMANs) for highly selective detection of unlabeled insulin in complex biological media using MALDI-TOF MS. The aptamer was easily anchored onto the gold nanoparticles in the mesochannels of MMANs with high capacity for highly efficient and specific enrichment of insulin. With the benefit from the size-exclusion effect of the mesoporous silica shell with a narrow pore size distribution (∼2.9 nm), insulin could be selectively detected despite interference from seven untargeted proteins with different size dimensions. This method exhibited an excellent response for insulin in the range 2-1000 ng mL(-1). Moreover, good recoveries in the detection of insulin in 20-fold diluted human serum were achieved. We anticipate that this novel method could be extended to other biomarkers of interest and potentially applied in disease diagnostics. PMID:25854412

  7. An alternative method to remove PEO-PPO-PEO template in organic-inorganic mesoporous nanocomposites by sulfuric acid extraction

    NASA Astrophysics Data System (ADS)

    Zhuang, Xin; Qian, Xufang; Lv, Jiahui; Wan, Ying

    2010-06-01

    Sulfuric acid is used as an extraction agent to remove PEO-PPO-PEO templates in the organic-inorganic mesoporous nanocomposites from the triconstituent co-assembly which includes the low-polymerized phenolic resins, TEOS and triblock copolymer F127. The XRD and TEM results show well ordered mesostructure after extraction with sulfuric acid. As followed from the N 2 sorption isotherms the extracted composites possess high surface areas (332-367 m 2/g), large pore volumes (0.66-0.78 cm 3/g), and large pore sizes (about 10.7 nm). The FT-IR analysis reveals almost complete elimination of triblock copolymer F127, and the maintenance of organic groups. This method shows potentials in removing templates from nanocomposites containing functional moieties.

  8. Fabrication of semi-aromatic polyamide/spherical mesoporous silica nanocomposite reverse osmosis membrane with superior permeability

    NASA Astrophysics Data System (ADS)

    Li, Qiang; Yu, Hui; Wu, Feiyang; Song, Jie; Pan, Xianhui; Zhang, Meng

    2016-02-01

    Semi-aromatic polyamide (SAP)/spherical mesoporous silica nanocomposite reverse osmosis (RO) membrane was successfully fabricated using m-phenylene diamine aqueous solution and cyclohexane-1,3,5-tricarbonyl chloride/mesoporous-silica-sphere (MSS) organic solution as main raw materials. The experimental suggests that the microstructures and surface features are significantly different from those of the contrast samples (the full- and semi-aromatic polyamide membranes), including the surface morphology, polymer framework structure, surface charge density, hydrophilicity, and the thickness of barrier layer. It was observed that many MSSs with ca. 1.5 nm of pore size are evenly embedded on the surface of the fabricated SAP/MSS RO membrane. Furthermore, the separation performance testing results indicate that the permeabilities range from 62.53 to 72.73 L/m2 h with the increase of the introduced MSSs from 0.02 to 0.08 w/v % under 1.5 MPa operating pressure and 2000 mg/L NaCl solution, which is obviously better than the contrast samples. Simultaneously, their salt rejections can be still maintained at a comparable level (94.78-91.46%). The excellent separation performance of the nanocomposite RO membrane is closely related to the higher-freedom-degree semi-aromatic framework, the incorporation of MSSs, the improved surface hydrophilicity, the thinner barrier layer, and the enhanced surface negative charge density.

  9. Facile large-scale synthesis of brain-like mesoporous silica nanocomposites via a selective etching process.

    PubMed

    Chen, Yu; Wang, Qihua; Wang, Tingmei

    2015-10-21

    The core-shell structured mesoporous silica nanomaterials (MSNs) are experiencing rapid development in many applications such as heterogeneous catalysis, bio-imaging and drug delivery wherein a large pore volume is desirable. We develop a one-pot method for large-scale synthesis of brain-like mesoporous silica nanocomposites based on the reasonable change of the intrinsic nature of the -Si-O-Si- framework of silica nanoparticles together with a selective etching strategy. The as-synthesized products show good monodispersion and a large pore volume of 1.0 cm(3) g(-1). The novelty of this approach lies in the use of an inorganic-organic hybrid layer to assist the creation of large-pore morphology on the outermost shell thereby promoting efficient mass transfer or storage. Importantly, the method is reliable and grams of products can be easily prepared. The morphology on the outermost silica shell can be controlled by simply adjusting the VTES-to-TEOS molar ratio (VTES: triethoxyvinylsilane, TEOS: tetraethyl orthosilicate) as well as the etching time. The as-synthesized products exhibit fluorescence performance by incorporating rhodamine B isothiocyanate (RITC) covalently into the inner silica walls, which provide potential application in bioimaging. We also demonstrate the applications of as-synthesized large-pore structured nanocomposites in drug delivery systems and stimuli-responsive nanoreactors for heterogeneous catalysis. PMID:26394819

  10. Mesoporous carbon-zirconium oxide nanocomposite derived from carbonized metal organic framework: A coating for solid-phase microextraction.

    PubMed

    Saraji, Mohammad; Mehrafza, Narges

    2016-08-19

    In this paper, a mesoporous carbon-ZrO2 nanocomposite was fabricated on a stainless steel wire for the first time and used as the solid-phase microextraction coating. The fiber was synthesized with the direct carbonization of a Zr-based metal organic framework. With the utilization of the metal organic framework as the precursor, no additional carbon source was used for the synthesis of the mesoporous carbon-ZrO2 nanocomposite coating. The fiber was applied for the determination of BTEX compounds (benzene, toluene, ethylbenzene and m, p-xylenes) in different water samples prior to gas chromatography-flame ionization detection. Such important experimental factors as synthesis time and temperature, salt concentration, equilibrium and extraction time, extraction temperature, desorption time and desorption temperature were studied and optimized. Good linearity in the concentration range of 0.2-200μgL(-1) and detection limits in the range of 0.05-0.56μgL(-1) was achieved for BTEX compounds. The intra- and inter-day relative standard deviations were in the range of 3.5-4.8% and 4.9-6.7%, respectively. The prepared fiber showed high capability for the analysis of BTEX compounds in different water and wastewater samples with good relative recoveries in the range of 93-107%. PMID:27451259

  11. Mesoporous ZnS–NiS Nanocomposites for Nonenzymatic Electrochemical Glucose Sensors

    PubMed Central

    Wei, Chengzhen; Cheng, Cheng; Zhao, Junhong; Wang, Zhangtao; Wu, Haipeng; Gu, Kaiyue; Du, Weimin; Pang, Huan

    2015-01-01

    Mesoporous ZnS–NiS composites are prepared via ion- exchange reactions using ZnS as the precursor. The prepared mesoporous ZnS–NiS composite materials have large surface areas (137.9 m2 g−1) compared with the ZnS precursor. More importantly, the application of these mesoporous ZnS–NiS composites as nonenzymatic glucose sensors was successfully explored. Electrochemical sensors based on mesoporous ZnS–NiS composites exhibit a high selectivity and a low detection limit (0.125 μm) toward the oxidation of glucose, which can mainly be attributed to the morphological characteristics of the mesoporous structure with high specific surface area and a rational composition of the two constituents. In addition, the mesoporous ZnS–NiS composites coated on the surface of electrodes can be used to modify the mass transport regime, and this alteration can, in favorable circumstances, facilitate the amperometric discrimination between species. These results suggest that such mesoporous ZnS–NiS composites are promising materials for nonenzymatic glucose sensors. PMID:25861568

  12. Ease synthesis of mesoporous WO3-TiO2 nanocomposites with enhanced photocatalytic performance for photodegradation of herbicide imazapyr under visible light and UV illumination.

    PubMed

    Ismail, Adel A; Abdelfattah, Ibrahim; Helal, Ahmed; Al-Sayari, S A; Robben, L; Bahnemann, D W

    2016-04-15

    Herein, we report the ease synthesis of mesoporous WO3-TiO2 nanocomposites at different WO3 contents (0-5wt%) together with their photocatalytic performance for the degradation of the imazapyr herbicide under visible light and UV illumination. XRD and Raman spectra indicated that the highly crystalline anatase TiO2 phase and monoclinic and triclinic of WO3 were formed. The mesoporous TiO2 exhibits large pore volumes of 0.267cm(3)g-1 and high surface areas of 180m(2)g(-1) but they become reduced to 0.221cm(3)g(-1) and 113m(2)g(-1), respectively upon WO3 incorporation, with tunable mesopore diameter in the range of 5-6.5nm. TEM images show WO3-TiO2 nanocomposites are quite uniform with 10-15nm of TiO2 and 5-10nm of WO3 sizes. Under UV illumination, the overall photocatalytic efficiency of the 3% WO3-TiO2 nanocomposite is 3.5 and 6.6 times higher than that of mesoporous TiO2 and commercial UV-100 photocatalyst, respectively. The 3% WO3-TiO2 nanocomposite is considered to be the optimum photocatalyst which is able to degrade completely (100% conversion) of imazapyr herbicide along 120min with high photonic efficiency ∼8%. While under visible light illumination, the 0.5% WO3-TiO2 nanocomposite is the optimum photocatalyst which achieves 46% photocatalytic efficiency. PMID:26775101

  13. Facile large-scale synthesis of brain-like mesoporous silica nanocomposites via a selective etching process

    NASA Astrophysics Data System (ADS)

    Chen, Yu; Wang, Qihua; Wang, Tingmei

    2015-10-01

    The core-shell structured mesoporous silica nanomaterials (MSNs) are experiencing rapid development in many applications such as heterogeneous catalysis, bio-imaging and drug delivery wherein a large pore volume is desirable. We develop a one-pot method for large-scale synthesis of brain-like mesoporous silica nanocomposites based on the reasonable change of the intrinsic nature of the -Si-O-Si- framework of silica nanoparticles together with a selective etching strategy. The as-synthesized products show good monodispersion and a large pore volume of 1.0 cm3 g-1. The novelty of this approach lies in the use of an inorganic-organic hybrid layer to assist the creation of large-pore morphology on the outermost shell thereby promoting efficient mass transfer or storage. Importantly, the method is reliable and grams of products can be easily prepared. The morphology on the outermost silica shell can be controlled by simply adjusting the VTES-to-TEOS molar ratio (VTES: triethoxyvinylsilane, TEOS: tetraethyl orthosilicate) as well as the etching time. The as-synthesized products exhibit fluorescence performance by incorporating rhodamine B isothiocyanate (RITC) covalently into the inner silica walls, which provide potential application in bioimaging. We also demonstrate the applications of as-synthesized large-pore structured nanocomposites in drug delivery systems and stimuli-responsive nanoreactors for heterogeneous catalysis.The core-shell structured mesoporous silica nanomaterials (MSNs) are experiencing rapid development in many applications such as heterogeneous catalysis, bio-imaging and drug delivery wherein a large pore volume is desirable. We develop a one-pot method for large-scale synthesis of brain-like mesoporous silica nanocomposites based on the reasonable change of the intrinsic nature of the -Si-O-Si- framework of silica nanoparticles together with a selective etching strategy. The as-synthesized products show good monodispersion and a large pore volume

  14. In Vivo Repeatedly Charging Near-Infrared-Emitting Mesoporous SiO2/ZnGa2O4:Cr3+ Persistent Luminescence Nanocomposites

    PubMed Central

    Li, Zhanjun; Zhang, Yuanwei; Wu, Xiang; Wu, Xiaoqiong; Maudgal, Rohit; Zhang, Hongwu

    2016-01-01

    Near-infrared (NIR) persistent phosphor ZnGa2O4:Cr3+ (ZGC) has unique deep-tissue rechargeable afterglow properties. However, the current synthesis leads to agglomerated products with irregular morphologies and wide size distributions. Herein, we report on in vivo rechargeable mesoporous SiO2/ZnGa2O4:Cr3+ (mZGC) afterglow NIR-emitting nanocomposites that are made by a simple, one-step mesoporous template method. At less than 600 °C, pores in mesoporous silica nanoparticles (MSNs) act as nanoreactors to generate in situ ZnGa2O4:Cr3+ NIR-persistent phosphors. The as-synthesized mZGC preserves defined size, morphology, and mesoporous nanostructure of the MSNs. The persistent luminescence of the as-synthesized mZGC is recharged in a simulated deep-tissue environment (e.g., ≈8 mm pork slab) in vitro by using red light (620 nm). Moreover, mZGC can be repeatedly activated in vivo for persistent luminescence imaging in a live mouse model by using white LED as a light source. Our concept of utilizing mesoporous silica as nanoreactor to fabricate ZGC PL nanoparticles with controllable morphology and preserved porous nanostructure paves a new way to the development and the wide application of deep tissue rechargeable ZGC in photonics and biophotonics.

  15. Synthesis and characterization of mesoporous zirconia nanocomposite using self-assembled block copolymer template

    NASA Astrophysics Data System (ADS)

    Ge, Qinwen

    Mesoporous zirconia has properties such as high surface area, uniform pore size distribution, and large pore volume, thus attracting great attention from the research community. Self-assembled structures have been used as directing agents to synthesize mesoporous zirconia. Here, we investigated the use of block copolymers conjugated to cationic biomolecules such as lysozyme, as well as cationic block copolymers as templates to synthesize mesoporous zirconia in completely aqueous media. Based on the Pluronic-lysozyme conjugate template, we further studied the effects of preparation conditions, including calcination temperature, precursor concentration, and precipitating pH. Several technics such as TGA, XRD, TEM, and N2 sorption were employed to characterize the zirconia samples. The results showed that tetragonal zirconia started to form after 300°C calcination and became fully crystallized after 500°C, grew larger when heated to higher temperatures, and began to form monoclinic phase after 900°C calcination. Our modified templates enhanced the thermal stability and increased the surface area of zirconia samples. The results also indicated that low precursor concentration and alkali media helped to decrease the zirconia particle size as well as increase the specific surface area. The surface area of the as-synthesized zirconia sample exhibited an increase before 500°C and a decrease after that, the highest specific surface area, 348 m2/g, achieved after 500°C calcination which was obtained using 0.08mol/L precursor at pH=10.

  16. Adsorptive interaction of bisphenol A with mesoporous titanosilicate/reduced graphene oxide nanocomposite materials: FT-IR and Raman analyses.

    PubMed

    Nguyen-Huy, Chinh; Kim, Nayoung; Nguyen-Phan, Thuy-Duong; Yoo, Ik-Keun; Shin, Eun Woo

    2014-01-01

    Nanocomposite materials containing graphene oxide have attracted tremendous interest as catalysts and adsorbents for water purification. In this study, mesoporous titanosilicate/reduced graphene oxide composite materials with different Ti contents were employed as adsorbents for removing bisphenol A (BPA) from water systems. The adsorptive interaction between BPA and adsorption sites on the composite materials was investigated by Fourier transform infrared (FT-IR) and Raman spectroscopy. Adsorption capacities of BPA at equilibrium, q e (mg/g), decreased with increasing Ti contents, proportional to the surface area of the composite materials. FT-IR observations for fresh and spent adsorbents indicated that BPA adsorbed onto the composite materials by the electrostatic interaction between OH functional groups contained in BPA and on the adsorbents. The electrostatic adsorption sites on the adsorbents were categorized into three hydroxyl groups: Si-OH, Ti-OH, and graphene-OH. In Raman spectra, the intensity ratios of D to G band were decreased after the adsorption of BPA, implying adsorptive interaction of benzene rings of BPA with the sp(2) hybrid structure of the reduced graphene oxide. PMID:25258598

  17. Adsorptive interaction of bisphenol A with mesoporous titanosilicate/reduced graphene oxide nanocomposite materials: FT-IR and Raman analyses

    NASA Astrophysics Data System (ADS)

    Nguyen-Huy, Chinh; Kim, Nayoung; Nguyen-Phan, Thuy-Duong; Yoo, Ik-Keun; Woo Shin, Eun

    2014-09-01

    Nanocomposite materials containing graphene oxide have attracted tremendous interest as catalysts and adsorbents for water purification. In this study, mesoporous titanosilicate/reduced graphene oxide composite materials with different Ti contents were employed as adsorbents for removing bisphenol A (BPA) from water systems. The adsorptive interaction between BPA and adsorption sites on the composite materials was investigated by Fourier transform infrared (FT-IR) and Raman spectroscopy. Adsorption capacities of BPA at equilibrium, q e (mg/g), decreased with increasing Ti contents, proportional to the surface area of the composite materials. FT-IR observations for fresh and spent adsorbents indicated that BPA adsorbed onto the composite materials by the electrostatic interaction between OH functional groups contained in BPA and on the adsorbents. The electrostatic adsorption sites on the adsorbents were categorized into three hydroxyl groups: Si-OH, Ti-OH, and graphene-OH. In Raman spectra, the intensity ratios of D to G band were decreased after the adsorption of BPA, implying adsorptive interaction of benzene rings of BPA with the sp2 hybrid structure of the reduced graphene oxide.

  18. Ge/GeO2-Ordered Mesoporous Carbon Nanocomposite for Rechargeable Lithium-Ion Batteries with a Long-Term Cycling Performance.

    PubMed

    Zeng, Lingxing; Huang, Xiaoxia; Chen, Xi; Zheng, Cheng; Qian, Qingrong; Chen, Qinghua; Wei, Mingdeng

    2016-01-13

    Germanium-based nanostructures are receiving intense interest in lithium-ion batteries because they have ultrahigh lithium ion storage ability. However, the Germanium-based anodes undergo the considerably large volume change during the charge/discharge processes, leading to a fast capacity fade. In the present work, a Ge/GeO2-ordered mesoporous carbon (Ge/GeO2-OMC) nanocomposite was successfully fabricated via a facile nanocasting route by using mesoporous carbon as a nanoreactor, and was then used as an anode for lithium-ion batteries. Benefited from its unique three-dimensional "meso-nano" structure, the Ge/GeO2-OMC nanocomposite exhibited large reversible capacity, excellent long-time cycling stability and high rate performance. For instance, a large reversible capacity of 1018 mA h g(-1) was obtained after 100 cycles at a current density of 0.1 A g(-1), which might be attributed to the unique structure of the Ge/GeO2-OMC nanocomposite. In addition, a reversible capacity of 492 mA h g(-1) can be retained when cycled to 500 cycles at a current density of 1 A g(-1). PMID:26651359

  19. Mesoporous anatase TiO{sub 2}/reduced graphene oxide nanocomposites: A simple template-free synthesis and their high photocatalytic performance

    SciTech Connect

    Zhou, Qi; Zhong, Yong-Hui; Chen, Xing; Huang, Xing-Jiu; Wu, Yu-Cheng

    2014-03-01

    Graphical abstract: - Highlights: • Mesoporous TiO{sub 2} nanoparticles with anatase phase were assembled on reduced graphene oxide via a template-free one-step hydrothermal method. • The TiO{sub 2}/rGO nanocomposites have better adsorption capacity and photocatalytic degradation efficiency for dyes removal. • Improved dye adsorption and photogenerated charge separation are responsible for enhanced activity. - Abstract: Mesoporous anatase phase TiO{sub 2} was assembled on reduced graphene oxide (rGO) using a template-free one-step hydrothermal process. The nanocomposites were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), Raman spectroscopy, and Brunauer–Emmett–Teller (BET) surface area. Morphology of TiO{sub 2} was related to the content of graphene oxide. TiO{sub 2}/rGO nanocomposites exhibited excellent photocatalytic activity for the photo-degradation of methyl orange. The degradation rate was 4.5 times greater than that of pure TiO{sub 2} nanoparticles. This difference was attributed to the thin two-dimensional graphene sheet. The graphene sheet had a large surface area, high adsorption capacity, and acted as a good electron acceptor for the transfer of photo-generated electrons from the conduction band of TiO{sub 2}. The enhanced surface adsorption characteristics and excellent charge transport separation were independent properties of the photocatalytic degradation process.

  20. Pd-loaded magnetic mesoporous nanocomposites: A magnetically recoverable catalyst with effective enrichment and high activity for DDT and DDE removal under mild conditions.

    PubMed

    Tian, Hua; Chen, Jun; He, Junhui; Liu, Feng

    2015-11-01

    1,1,1-Trichloro-2,2-bis(4-chlorophenyl) ethane (DDT), an organochlorine pollutant, is highly persistent in environment and responsible for many ecological and health damages. Although remediation and degradation of DDT and its metabolites in soil and water by microorganisms and abiotic techniques can be accomplished, success is often accompanied by rigorous reaction conditions, such as anaerobic system, explosive gases, high pressure or temperature, and illumination. Here a triple-functional nanocomposite was prepared by integrating superparamagnetic Fe3O4 and palladium (Pd) nanoparticles onto mesoporous Fe3O4@nSiO2@mSiO2 nanospheres. These magnetic mesoporous materials display excellent capabilities of capturing and catalytically degrading DDT in water. Over these nanocomposites, DDT and its metabolite, 1,1-dichloro-2,2-bis(4-chlorophenyl) ethylene (DDE) could be quickly enriched and completely degraded at as low as 150 °C. The nanocomposites can be magnetically separated from the dispersion after adsorption, and then be easily regenerated which is accompanied by catalytic reaction. The whole treatment process is convenient, energy-saving, and just requires ambient pressure and mild reaction conditions. PMID:26188725

  1. Facile synthesis of gold@graphitized mesoporous silica nanocomposite and its surface-assisted laser desorption/ionization for time-of-flight mass spectroscopy.

    PubMed

    Xu, Guiju; Liu, Shengju; Peng, Jiaxi; Lv, Wenping; Wu, Ren'an

    2015-01-28

    In this work, a novel core-shell structured gold@graphitized mesoporous silica nanocomposite (Au@GMSN) was synthesized by in situ graphitization of template within the mesochannels of mesoporous silica shell on gold core and demonstrated to be promising nanomaterials for surface-assisted laser desorption/ionization time-of-flight mass spectroscopy (SALDI-TOF MS). The integration of the graphitized mesoporous silica with the gold nanoparticles endowed Au@GMSN with large surface areas of graphitic structure, good dispersibility, and strong ultraviolet (UV) absorption. Au@GMSN exerted the synergistic effect on the efficient detection of small-molecular-weight analytes including amino acids, neutral saccharides, peptides, and traditional Chinese medicine. The Au@GMSN-assisted laser desorption/ionization exhibited the following superiorities: high ionization efficiency, low fragmentation interference, favorable salt tolerance, and good reproducibility. Moreover, because of the large hydrophobic inner surface area of the graphitized mesoporous silica shell, the Au@GMSN demonstrated its promising capacity in the pre-enrichment of aromatic analytes prior to SALDI-TOF MS, which favored rapid and sensitive detection. PMID:25552293

  2. Anhydrous phosphoric Acid functionalized sintered mesoporous silica nanocomposite proton exchange membranes for fuel cells.

    PubMed

    Zeng, Jie; He, Beibei; Lamb, Krystina; De Marco, Roland; Shen, Pei Kang; Jiang, San Ping

    2013-11-13

    A novel inorganic proton exchange membrane based on phosphoric acid (PA)-functionalized sintered mesoporous silica, PA-meso-silica, has been developed and investigated. After sintering at 650 °C, the meso-silica powder forms a dense membrane with a robust and ordered mesoporous structure, which is critical for retention of PA and water within the porous material. The PA-meso-silica membrane achieved a high proton conductivity of 5 × 10(-3) to 5 × 10(-2) S cm(-1) in a temperature range of 80-220 °C, which is between 1 and 2 orders of magnitudes higher than a typical membrane Nafion 117 or polybenzimidazole (PBI)/PA in the absence of external humidification. Furthermore, the PA-meso-silica membranes exhibited good chemical stability along with high performance at elevated temperatures, producing a peak power density of 632 mW cm(-2) using a H2 fuel at 190 °C in the absence of external humidification. The high membrane proton conductivity and excellent fuel cell performance demonstrate the utility of PA-meso-silica as a new class of inorganic proton exchange membranes for use in the high-temperature proton exchange membrane fuel cells (PEMFCs). PMID:24125494

  3. Mesoporous nickel-aluminosilicate nanocomposite: a solid acid catalyst for ether synthesis.

    PubMed

    Neelakandeswari, N; Karvembu, R; Dharmaraj, N

    2013-04-01

    Mesoporous nickel aluminosilicate, a solid acid catalyst prepared by sol-gel technique was utilized as a heterogeneous catalyst for the synthesis of symmetrical ethers by dehydro-condensation of alcohols. The prepared catalysts were characterized by Fourier-transform infra red spectroscopy (FT-IR), powder X-ray diffraction (XRD), scanning electron microscopy (SEM), energy dispersive X-ray analysis (EDAX), N2 adsorption-desorption analysis, temperature programmed desorption of ammonia (TPD) and X-ray photoelectron spectroscopic techniques. The presence of the catalyst assisted the etherification reaction in 30 minutes. Ethers formed in these reactions were quantified by gas chromatography (GC) and the identities of few of them were confirmed by nuclear magnetic resonance spectral data (NMR). PMID:23763171

  4. A multifunctional mesoporous silica nanocomposite for targeted delivery, controlled release of doxorubicin and bioimaging.

    PubMed

    Xie, Meng; Shi, Hui; Li, Zhen; Shen, Haijun; Ma, Kun; Li, Bo; Shen, Song; Jin, Yi

    2013-10-01

    In this study, a targeting drug delivery system based on mesoporous silica nanoparticle (MSN) was successfully developed for anti-cancer drug delivery and bioimaging. Carboxyl functionalized MSN (MSN/COOH) was firstly prepared and then modified with folate as the cancer targeting moiety and a near infrared fluorescent dye as labeling segment. Folate was conjugated to MSN/COOH via functional polyethyleneglycol (PEG), constructing the vector MSN/COOH-PEG-FA. The functionalization with carboxyl caused the pore surface of the nanocarrier more negative than native MSN, which could provide attractive forces between the nanoparticles and positively charged doxorubicin hydrochloride (DOX). Meanwhile, the folate modification significantly enhanced the cellular uptake of the delivery system compared to unmodified counterparts. Furthermore, the introduction of PEG increased the water dispersibility. Besides, the modification with the near infrared fluorescent dye Cy5 made the system effective for live cell and in vivo imaging. Therefore, the Cy5-MSN/COOH-PEG-FA system could be a promising nanocarrier for simultaneous diagnosis and treatment of diseases. PMID:23711784

  5. Deposition of luminescent Y2O3:Eu3+ on ferromagnetic mesoporous CoFe2O4@mSiO2 nanocomposites.

    PubMed

    Ren, Xiaozhen; Tong, Lizhu; Chen, Xiaodong; Ding, Hong; Yang, Xuwei; Yang, Hua

    2014-06-14

    Luminescent Y2O3:Eu(3+) particles have been deposited on the surface of ferromagnetic mesoporous CoFe2O4@mSiO2 nanoparticles by a co-precipitation method, obtaining multifunctional CoFe2O4@mSiO2@Y2O3:Eu(3+) nanocomposites. XRD, SEM, TEM, EDX, XPS, N2-adsorption-desorption, FT-IR, VSM and PL were used to characterized the samples. The results reveal that the nanocomposites display typical mesoporous characteristics with high surface areas (BET), large pore volumes and core-shell structures. The composites show ferromagnetic properties and red luminescence from the (5)D0-(7)F2 transition at 610 nm. The size and the magnetic and luminescence properties of the composites could be tuned by systematically varying the experimental parameters, such as the annealing temperature, the mass ratio of CoFe2O4@mSiO2 to Y2O3:Eu(3+), and the volume of TEOS. A possible quenching mechanism of the luminescent Y2O3:Eu(3+) by the ferromagnetic CoFe2O4 is proposed. The high BET and large pore volume may give the composite potential application in controlled drug release. PMID:24741669

  6. Engineering 3D bicontinuous hierarchically macro-mesoporous LiFePO4/C nanocomposite for lithium storage with high rate capability and long cycle stability

    NASA Astrophysics Data System (ADS)

    Zhang, Qian; Huang, Shao-Zhuan; Jin, Jun; Liu, Jing; Li, Yu; Wang, Hong-En; Chen, Li-Hua; Wang, Bin-Jie; Su, Bao-Lian

    2016-05-01

    A highly crystalline three dimensional (3D) bicontinuous hierarchically macro-mesoporous LiFePO4/C nanocomposite constructed by nanoparticles in the range of 50~100 nm via a rapid microwave assisted solvothermal process followed by carbon coating have been synthesized as cathode material for high performance lithium-ion batteries. The abundant 3D macropores allow better penetration of electrolyte to promote Li+ diffusion, the mesopores provide more electrochemical reaction sites and the carbon layers outside LiFePO4 nanoparticles increase the electrical conductivity, thus ultimately facilitating reverse reaction of Fe3+ to Fe2+ and alleviating electrode polarization. In addition, the particle size in nanoscale can provide short diffusion lengths for the Li+ intercalation-deintercalation. As a result, the 3D macro-mesoporous nanosized LiFePO4/C electrode exhibits excellent rate capability (129.1 mA h/g at 2 C; 110.9 mA h/g at 10 C) and cycling stability (87.2% capacity retention at 2 C after 1000 cycles, 76.3% at 5 C after 500 cycles and 87.8% at 10 C after 500 cycles, respectively), which are much better than many reported LiFePO4/C structures. Our demonstration here offers the opportunity to develop nanoscaled hierarchically porous LiFePO4/C structures for high performance lithium-ion batteries through microwave assisted solvothermal method.

  7. Gold nanorods/mesoporous silica-based nanocomposite as theranostic agents for targeting near-infrared imaging and photothermal therapy induced with laser

    PubMed Central

    Liu, Yang; Xu, Ming; Chen, Qing; Guan, Guannan; Hu, Wen; Zhao, Xiuli; Qiao, Mingxi; Hu, Haiyang; Liang, Ying; Zhu, Heyun; Chen, Dawei

    2015-01-01

    Photothermal therapy (PTT) is widely regarded as a promising technology for cancer treatment. Gold nanorods (GNRs), as excellent PTT agent candidates, have shown high-performance photothermal conversion ability under laser irradiation, yet two major obstacles to their clinical application are the lack of selective accumulation in the target site following systemic administration and the greatly reduced photothermal conversion efficiency caused by self-aggregating in aqueous environment. Herein, we demonstrate that tLyp-1 peptide-functionalized, indocyanine green (ICG)-containing mesoporous silica-coated GNRs (I-TMSG) possessed dual-function as tumor cells-targeting near-infrared (NIR) fluorescent probe and PTT agents. The construction of the nanostructure began with synthesis of GNRs by seed-mediated growth method, followed by the coating of mesoporous silica, the chemical conjugation of PEG and tLyp-1 peptide, and the enclosure of ICG as an NIR imaging agent in the mesoporous. The as-prepared nanoparticles could shield the GNRs against their self-aggregation, improve the stability of ICG, and exhibit negligible dark cytotoxicity. More importantly, such a theranostic nanocomposite could realize the combination of GNRs-based photothermal ablation under NIR illumination, ICG-mediated fluorescent imaging, and tLyp-1-enabled more easy endocytosis into breast cancer cells. All in all, I-TMSG nanoparticles, in our opinion, possessed the strong potential to realize the effective diagnosis and PTT treatment of human mammary cancer. PMID:26251596

  8. Engineering 3D bicontinuous hierarchically macro-mesoporous LiFePO4/C nanocomposite for lithium storage with high rate capability and long cycle stability

    PubMed Central

    Zhang, Qian; Huang, Shao-Zhuan; Jin, Jun; Liu, Jing; Li, Yu; Wang, Hong-En; Chen, Li-Hua; Wang, Bin-Jie; Su, Bao-Lian

    2016-01-01

    A highly crystalline three dimensional (3D) bicontinuous hierarchically macro-mesoporous LiFePO4/C nanocomposite constructed by nanoparticles in the range of 50~100 nm via a rapid microwave assisted solvothermal process followed by carbon coating have been synthesized as cathode material for high performance lithium-ion batteries. The abundant 3D macropores allow better penetration of electrolyte to promote Li+ diffusion, the mesopores provide more electrochemical reaction sites and the carbon layers outside LiFePO4 nanoparticles increase the electrical conductivity, thus ultimately facilitating reverse reaction of Fe3+ to Fe2+ and alleviating electrode polarization. In addition, the particle size in nanoscale can provide short diffusion lengths for the Li+ intercalation-deintercalation. As a result, the 3D macro-mesoporous nanosized LiFePO4/C electrode exhibits excellent rate capability (129.1 mA h/g at 2 C; 110.9 mA h/g at 10 C) and cycling stability (87.2% capacity retention at 2 C after 1000 cycles, 76.3% at 5 C after 500 cycles and 87.8% at 10 C after 500 cycles, respectively), which are much better than many reported LiFePO4/C structures. Our demonstration here offers the opportunity to develop nanoscaled hierarchically porous LiFePO4/C structures for high performance lithium-ion batteries through microwave assisted solvothermal method. PMID:27181195

  9. Engineering 3D bicontinuous hierarchically macro-mesoporous LiFePO4/C nanocomposite for lithium storage with high rate capability and long cycle stability.

    PubMed

    Zhang, Qian; Huang, Shao-Zhuan; Jin, Jun; Liu, Jing; Li, Yu; Wang, Hong-En; Chen, Li-Hua; Wang, Bin-Jie; Su, Bao-Lian

    2016-01-01

    A highly crystalline three dimensional (3D) bicontinuous hierarchically macro-mesoporous LiFePO4/C nanocomposite constructed by nanoparticles in the range of 50~100 nm via a rapid microwave assisted solvothermal process followed by carbon coating have been synthesized as cathode material for high performance lithium-ion batteries. The abundant 3D macropores allow better penetration of electrolyte to promote Li(+) diffusion, the mesopores provide more electrochemical reaction sites and the carbon layers outside LiFePO4 nanoparticles increase the electrical conductivity, thus ultimately facilitating reverse reaction of Fe(3+) to Fe(2+) and alleviating electrode polarization. In addition, the particle size in nanoscale can provide short diffusion lengths for the Li(+) intercalation-deintercalation. As a result, the 3D macro-mesoporous nanosized LiFePO4/C electrode exhibits excellent rate capability (129.1 mA h/g at 2 C; 110.9 mA h/g at 10 C) and cycling stability (87.2% capacity retention at 2 C after 1000 cycles, 76.3% at 5 C after 500 cycles and 87.8% at 10 C after 500 cycles, respectively), which are much better than many reported LiFePO4/C structures. Our demonstration here offers the opportunity to develop nanoscaled hierarchically porous LiFePO4/C structures for high performance lithium-ion batteries through microwave assisted solvothermal method. PMID:27181195

  10. Gold nanorods/mesoporous silica-based nanocomposite as theranostic agents for targeting near-infrared imaging and photothermal therapy induced with laser.

    PubMed

    Liu, Yang; Xu, Ming; Chen, Qing; Guan, Guannan; Hu, Wen; Zhao, Xiuli; Qiao, Mingxi; Hu, Haiyang; Liang, Ying; Zhu, Heyun; Chen, Dawei

    2015-01-01

    Photothermal therapy (PTT) is widely regarded as a promising technology for cancer treatment. Gold nanorods (GNRs), as excellent PTT agent candidates, have shown high-performance photothermal conversion ability under laser irradiation, yet two major obstacles to their clinical application are the lack of selective accumulation in the target site following systemic administration and the greatly reduced photothermal conversion efficiency caused by self-aggregating in aqueous environment. Herein, we demonstrate that tLyp-1 peptide-functionalized, indocyanine green (ICG)-containing mesoporous silica-coated GNRs (I-TMSG) possessed dual-function as tumor cells-targeting near-infrared (NIR) fluorescent probe and PTT agents. The construction of the nanostructure began with synthesis of GNRs by seed-mediated growth method, followed by the coating of mesoporous silica, the chemical conjugation of PEG and tLyp-1 peptide, and the enclosure of ICG as an NIR imaging agent in the mesoporous. The as-prepared nanoparticles could shield the GNRs against their self-aggregation, improve the stability of ICG, and exhibit negligible dark cytotoxicity. More importantly, such a theranostic nanocomposite could realize the combination of GNRs-based photothermal ablation under NIR illumination, ICG-mediated fluorescent imaging, and tLyp-1-enabled more easy endocytosis into breast cancer cells. All in all, I-TMSG nanoparticles, in our opinion, possessed the strong potential to realize the effective diagnosis and PTT treatment of human mammary cancer. PMID:26251596

  11. A luminescent and mesoporous core-shell structured Gd2O3 : Eu(3+)@nSiO2@mSiO2 nanocomposite as a drug carrier.

    PubMed

    Xu, Zhenhe; Gao, Yu; Huang, Shanshan; Ma, Ping' an; Lin, Jun; Fang, Jiye

    2011-05-14

    In this paper, Gd(2)O(3) : Eu(3+) nanospheres have been encapsulated with nonporous silica and further layer of ordered mesoporous silica through a simple sol-gel process. X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), N(2) adsorption/desorption, photoluminescence (PL) spectra, and kinetic decay were used to characterize the sample. The results indicate that the nanocomposite with general 50 nm shell thickness and 270 nm core size shows typical ordered mesoporous characteristics (2.4 nm) and has spherical morphology with a smooth surface and narrow size distribution. Additionally, the obtained inorganic nanocomposite shows the characteristic emission of Eu(3+) ((5)D(0)→(7)F(1-4)) even after the loading of drug molecules. The biocompatibility test on L929 fibroblast cells using MTT assay reveals low cytotoxicity of the system. Most importantly, the nanocomposite can be used as an effective drug delivery carrier. A typical anticancer drug, doxorubicin hydrochloride (DOX), was used for drug loading, and the DOX release, cytotoxicity, uptake behavior and therapeutic effects were examined. It was found that DOX is shuttled into the cell by the nanocomposite and released inside cells after endocytosis and that the DOX-loaded nanocomposite exhibited greater cytotoxicity than free DOX. These results indicate that core-shell structured Gd(2)O(3) : Eu(3+)@nSiO(2)@mSiO(2) nanocomposite has potential for drug loading and delivery into cancer cells to induce cell death. PMID:21431226

  12. Enhanced photocatalytic activity of nitrogen and indium co-doped mesoporous TiO2 nanocomposites for the degradation of 2,4-dinitrophenol under visible light

    NASA Astrophysics Data System (ADS)

    Myilsamy, M.; Mahalakshmi, M.; Murugesan, V.; Subha, N.

    2015-07-01

    Mesoporous N/In2O3-TiO2 nanocomposite photocatalysts were synthesized by sol-gel route using Pluronic P123 as the structure directing template. The synthesized composite materials were successfully characterized by X-ray powder diffraction, high resolution transmission electron microscopy, N2 adsorption-desorption studies, X-ray photoelectron spectroscopy, diffuse reflectance UV-vis spectroscopy, Fourier transform infrared spectroscopy and photoluminescence spectroscopy. The photocatalytic activities of all the synthesized catalysts were evaluated for the degradation of 2,4-dinitrophenol under visible light irradiation. The results demonstrated that the mesoporous N/In2O3-TiO2 showed higher efficiency than meso TiO2, N-TiO2 and In2O3-TiO2 under visible light irradiation and the optimum molar ratio of N and In to Ti is 0.3 wt%. DRUV-vis revealed that the substitution of N- and In3+ dopants on TiO2 lattice shifted the light absorption to the longer wavelength and reduced the band gap energy. The enhanced •OH radicals formation during the photocatalytic reaction was revealed by photoluminescence spectra. The photoluminescence spectra of synthesized catalysts revealed that the efficient charge separation of photo induced charge carriers for 0.3 wt% N/In2O3-TiO2 nanocomposite. The enhanced surface area, large pore volume and large pore diameter for 0.3 wt% N/In2O3-TiO2 improved the photocatalytic efficiency. In3+ ions can easily trap and transfer the excited electrons to the adsorbed O2 molecules, hence efficiently extending the life time of electron-hole pair.

  13. Facile synthesis of Fe3O4-graphene@mesoporous SiO2 nanocomposites for efficient removal of Methylene Blue

    NASA Astrophysics Data System (ADS)

    Wu, Xi-Lin; Shi, Yanpeng; Zhong, Shuxian; Lin, Hongjun; Chen, Jian-Rong

    2016-08-01

    Herein, we have developed a facile and low-cost method for the synthesis of novel graphene based nanosorbents. Firstly, well-defined Fe3O4 nanoparticles were decorated onto graphene sheets, and then a layer of mesoporous SiO2 were deposited on the surface of the Fe3O4-graphene composites. The obtained Fe3O4-graphene@mesoporous SiO2 nanocomposites (denoted as MG@m-SiO2) were characterized by scanning electron microscopic (SEM), transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), Fourier transformed infrared (FTIR) spectroscopy and X-ray diffraction (XRD). The adsorptive property was investigated by using MG@m-SiO2 as sorbents and Methylene Blue (MB), a common dye, as model of the organic pollutants. Adsorption kinetics, isotherms, thermodynamics as well as effects of pH and adsorbent dose on the adsorption were studied. The adsorption isotherms and kinetics are better described by Langmuir isotherm model and pseudo-second-order kinetic model, respectively. Thermodynamic studies suggest that the adsorption of MB onto the MG@m-SiO2 is endothermic and spontaneous process. The results imply that the MG@m-SiO2 can be served as a cost-effective adsorbent for the removal of organic pollutants from aqueous solutions.

  14. A novel mesoporous carbon-silica-titania nanocomposite as a high performance anode material in lithium ion batteries.

    PubMed

    Zhou, Yuanyuan; Kim, Younghun; Jo, Changshin; Lee, Jinwoo; Lee, Chul Wee; Yoon, Songhun

    2011-05-01

    An ordered mesoporous carbon-silica-titania material was prepared using the tetra-constituents co-assembly method. As regards its anode performance in lithium ion batteries, the composite material anode exhibited a high capacity (875 mAh g(-1)), a higher initial efficiency (56%) and an improved rate. PMID:21424009

  15. Nanocomposite of TiO2 and Mesoporous Carbon for High Power Anode of Lithium Rechargeable Batteries.

    PubMed

    Kim, Jun-Il; Lee, Jae-Won

    2015-11-01

    A composite of TiO2 and MgO-templated disordered mesoporous carbon was prepared through infiltrating precursor solution (titanium isopropoxide) into the carbon matrix and growing TiO2 nanocrystals in the pore of the carbon. Transmission electron microscope (TEM) and scanning electron microscope (SEM) image showed that TiO2 nanoparticles are embedded homogeneously in the mesoporous carbon matrix without formation of big particles out of the pores or agglomeration. The electrochemical properties were evaluated by galvanostatic charge/discharge cycling. The composite electrode material showed excellent high-rate characteristics and cycling stability. Uniform dispersion of the TiO2 nanoparticles over the carbon matrix is believed to enhance the electronic conductivity and Li+ ion diffusion of the composite electrode material and thus result in good rate capability. PMID:26726659

  16. Nanocomposites with graft copolymer-templated mesoporous MgTiO3 perovskite for CO2 capture applications.

    PubMed

    Roh, Dong Kyu; Kim, Sang Jin; Jeon, Harim; Kim, Jong Hak

    2013-07-24

    Mesoporous MgTiO3 perovskite with a high porosity and interfacial properties were synthesized via a solvothermal reaction at 150 °C for 10 h using a graft copolymer, i.e., poly(vinyl chloride)-g-poly(oxyethylene methacrylate) (PVC-g-POEM) with a well-ordered micellar morphology as a structure-directing agent. A PVC-g-POEM graft copolymer with a wormlike morphology was utilized as a soft matrix to prepare a mixed matrix membrane (MMM) with mesoporous MgTiO3 perovskite through a solution-casting method. The structure and morphology of PVC-g-POEM graft copolymer was carefully tuned by controlling polymer-solvent interactions, as characterized by transmission electron microscopy (TEM). The average pore diameter of the MgTiO3 perovskite was 10.4 nm, which is effective in facilitating gas transport via Knudsen diffusion through mesopores as well as improving interfacial contact with the organic polymer matrix. Because of a high porosity (0.56), the density of mesoporous MgTiO3 (1.75 g/cm(3)) was much lower than that of dense nonporous MgTiO3 (4 g/cm(3)) and not significantly higher than that of PVC-g-POEM (1.25 g/cm(3)), leading to a uniform distribution of MgTiO3 in MMM. The permeability of MMM with MgTiO3 was greater than those of MMM with only MgO or TiO2, indicating the simultaneous improvement of solubility and diffusivity in the former, as supported by CO2 temperature-programmed desorption (TPD) measurements. The MMM with MgTiO3 25 wt % exhibited a CO2 permeability improvement of 140% up to 138.7 Barrer (1 Barrer = 1 × 10(-10) cm(3)(STP) cm cm(-2) s(-1) cmHg(-1)) without a large loss of CO2/N2 selectivity. PMID:23777632

  17. Synthesis and characterization of mesoporous ceria/alumina nanocomposite materials via mixing of the corresponding ceria and alumina gel precursors.

    PubMed

    Khalil, Kamal M S

    2007-03-01

    Mesoporous ceria/alumina, CeO(2)/Al(2)O(3), composites containing 10, 20 and 30% (w/w) ceria were prepared by a novel gel mixing method. In the method, ceria gel (formed via hydrolysis of ammonium cerium(IV) nitrate by aqueous ammonium carbonate solution) and alumina gel (formed via controlled hydrolysis of aluminum tri-isopropoxide) were mixed together. The mixed gel was subjected to subsequent drying and calcination for 3 h at 400, 600, 800 and 1000 degrees C. The uncalcined (dried at 110 degrees C) and the calcined composites were investigated by different techniques including TGA, DSC, FTIR, XRD, SEM and nitrogen adsorption/desorption isotherms. Results indicated that composites calcined for 3 h at 800 degrees C mainly kept amorphous alumina structure and gamma-alumina formed only upon calcinations at 1000 degrees C. On the other hand, CeO(2) was found to crystallize in the common ceria, cerinite, phase and it kept this structure over the entire calcination range (400-1000 degrees C). Therefore, high surface areas, stable surface textures, and non-aggregated nano-sized ceria dispersions were obtained. A systematic texture change based on ceria ratio was observed, however in all cases mesoporous composite materials exposing thermally stable texture and structure were obtained. The presented method produces composite ceria/alumina materials that suit different applications in the field of catalysis and membranes technology, and throw some light on physicochemical factors that determine textural morphology and thermal stability of such important composite. PMID:17182052

  18. Nanocomposite

    NASA Astrophysics Data System (ADS)

    Seifzadeh, Davod; Rahimzadeh Hollagh, Amin

    2014-11-01

    Electroless Ni-Co-P coating and Ni-Co-P-SiO2 nanocomposites were successfully applied on AZ91D magnesium alloy via environmentally friendly cerium-lanthanum-permanganate treatment and their properties were compared with traditionally binary Ni-P coating. The prepared coatings were analyzed using scanning electron microscopy, x-ray diffraction, and energy dispersive x-ray spectroscopy. Moreover, the corrosion behavior of the coatings in 3.5 wt.% NaCl was evaluated by two electrochemical methods. It is found that the Ni-Co-P coating possesses more uniform and compact structure and better corrosion protection characteristics in comparison with the Ni-P coating. The plating rate of Ni-Co-P bath is relatively lower than the Ni-P bath, but it significantly increases after addition of SiO2 nanoparticles more probably due to adsorption of silica nanoparticles on alloy surface. The corrosion resistance of Ni-Co-P-SiO2 composite coatings was superior with respect to Ni-P and Ni-Co-P coatings due to formation of thick and compact coating with tortuous grain boundaries.

  19. Mesoporous Silica Particles Integrated with All-Inorganic CsPbBr3 Perovskite Quantum-Dot Nanocomposites (MP-PQDs) with High Stability and Wide Color Gamut Used for Backlight Display.

    PubMed

    Wang, Hung-Chia; Lin, Shin-Ying; Tang, An-Cih; Singh, Bheeshma Pratap; Tong, Hung-Chun; Chen, Ching-Yi; Lee, Yu-Chun; Tsai, Tzong-Liang; Liu, Ru-Shi

    2016-07-01

    All-inorganic CsPbX3 (X=I, Br, Cl) perovskite quantum dots (PQDs) have been investigated because of their optical properties, such as tunable wavelength, narrow band, and high quantum efficiency. These features have been used in light emitting diode (LED) devices. LED on-chip fabrication uses mixed green and red quantum dots with silicone gel. However, the ion-exchange effect widens the narrow emission spectrum. Quantum dots cannot be mixed because of anion exchange. We address this issue with a mesoporous PQD nanocomposite that can prevent ion exchange and increase stability. We mixed green quantum-dot-containing mesoporous silica nanocomposites with red PQDs, which can prevent the anion-exchange effect and increase thermal and photo stability. We applied the new PQD-based LEDs for backlight displays. We also used PQDs in an on-chip LED device. Our white LED device for backlight display passed through a color filter with an NTSC value of 113 % and Rec. 2020 of 85 %. PMID:27239980

  20. S-doped mesoporous nanocomposite of HTiNbO5 nanosheets and TiO2 nanoparticles with enhanced visible light photocatalytic activity.

    PubMed

    Liu, Chao; Han, Ruirui; Ji, Hongmei; Sun, Tao; Zhao, Jin; Chen, Ningna; Chen, Jing; Guo, Xuefeng; Hou, Wenhua; Ding, Weiping

    2016-01-14

    The S-doped mesoporous nanocomposite (S-TNT) of HTiNbO5 nanosheets (NSs) and anatase TiO2 nanoparticles (NPs) with exposed {101} facets has been successfully synthesized by first mixing freeze-dried HTiNbO5 NSs with titanium isopropoxide and then calcination with thiourea in air. The exposed anatase {101} facets can act as a possible reservoir of the photogenerated electrons, yielding a highly reactive surface for the reduction of O2 to O2˙(-). The partial substitution of Ti(4+) by S(6+) in the lattice of TiO2 NPs leads to a charge imbalance in S-TNT and the formation of Ti-O-S bonds. As a result, the formed cationic S-TNT favours adsorption of hydroxide ions (OH(-)(ads)) and thus captures the photo-induced holes to form hydroxyl radicals (˙OH). Moreover, with the formation of Ti-O-S bonds, partial electrons can be transferred from S to O atoms and hence the electron-deficient S atoms might capture photo-induced electrons. The surface-adsorbed SO4(2-) could also act as an efficient electron trapping center to promote the separation of charge carriers. In addition, the Ti(3+) species due to the removal of oxygen atoms during calcination and the associated oxygen vacancy defects on the surface of S-TNT could act as hole and electron scavengers, respectively. Besides, the closely contacted interface is formed between HTiNbO5 NSs and anatase TiO2 NPs due to the common features of TiO6 octahedra in two components, resulting in a nanoscale heterojunction structure to speed up the separation rate of photogenerated charge carriers. The formation of a nano-heterojunction and the incorporation of Ti(3+) and S dopants give rise to the visible and near-infrared light response of S-TNT. The combined effects greatly retard the charge recombination and improve the photocatalytic activity for the degradation of rhodamine B (RhB) and phenol solution under visible light irradiation. The corresponding photocatalytic mechanism was investigated via the active species capture

  1. Hierarchical TiO2/C nanocomposite monoliths with a robust scaffolding architecture, mesopore-macropore network and TiO2-C heterostructure for high-performance lithium ion batteries.

    PubMed

    Huang, Hai-Bo; Yang, Yue; Chen, Li-Hua; Wang, Yun; Huang, Shao-Zhuan; Tao, Jia-Wei; Ma, Xiao-Ting; Hasan, Tawfique; Li, Yu; Xu, Yan; Su, Bao-Lian

    2016-06-01

    Engineering hierarchical structures of electrode materials is a powerful strategy for optimizing the electrochemical performance of an anode material for lithium-ion batteries (LIBs). Herein, we report the fabrication of hierarchical TiO2/C nanocomposite monoliths by mediated mineralization and carbonization using bacterial cellulose (BC) as a scaffolding template as well as a carbon source. TiO2/C has a robust scaffolding architecture, a mesopore-macropore network and TiO2-C heterostructure. TiO2/C-500, obtained by calcination at 500 °C in nitrogen, contains an anatase TiO2-C heterostructure with a specific surface area of 66.5 m(2) g(-1). When evaluated as an anode material at 0.5 C, TiO2/C-500 exhibits a high and reversible lithium storage capacity of 188 mA h g(-1), an excellent initial capacity of 283 mA h g(-1), a long cycle life with a 94% coulombic efficiency preserved after 200 cycles, and a very low charge transfer resistance. The superior electrochemical performance of TiO2/C-500 is attributed to the synergistic effect of high electrical conductivity, anatase TiO2-C heterostructure, mesopore-macropore network and robust scaffolding architecture. The current material strategy affords a general approach for the design of complex inorganic nanocomposites with structural stability, and tunable and interconnected hierarchical porosity that may lead to the next generation of electrochemical supercapacitors with high energy efficiency and superior power density. PMID:26864500

  2. A self-reductive mesoporous CuO(x)/Fe/silicate nanocomposite as a highly active and stable catalyst for methanol reforming.

    PubMed

    Li, Chien-Cheng; Chen, Yan-Wun; Lin, Ran-Jin; Chang, Ching-Chun; Chen, Kuei-Hsien; Lin, Hong-Ping; Chen, Li-Chyong

    2011-09-01

    A simple and convenient one-pot synthetic route to directly prepare a self-reductive mesoporous copper-iron-silicate (CuO(x)-Fe-silicate)-based catalyst has been developed. The resultant catalyst is highly active and stable in methanol reforming without needing a pre-reduction procedure. PMID:21773606

  3. Mesoporous carbon/zirconia composites: a potential route to chemically functionalized electrically-conductive mesoporous materials.

    PubMed

    Oh, Jung-Min; Kumbhar, Amar S; Geiculescu, Olt; Creager, Stephen E

    2012-02-14

    Mesoporous nanocomposite materials in which nanoscale zirconia (ZrO(2)) particles are embedded in the carbon skeleton of a templated mesoporous carbon matrix were prepared, and the embedded zirconia sites were used to accomplish chemical functionalization of the interior surfaces of mesopores. These nanocomposite materials offer a unique combination of high porosity (e.g., ∼84% void space), electrical conductivity, and surface tailorability. The ZrO(2)/carbon nanocomposites were characterized by thermogravimetric analysis, nitrogen-adsorption porosimetry, helium pychnometry, powder X-ray diffraction, Raman spectroscopy, scanning electron microscopy, transmission electron microscopy, and X-ray photoelectron spectroscopy. Comparison was made with templated mesoporous carbon samples prepared without addition of ZrO(2). Treatment of the nanocomposites with phenylphosphonic acid was undertaken and shown to result in robust binding of the phosphonic acid to the surface of ZrO(2) particles. Incorporation of nanoscale ZrO(2) surfaces in the mesoporous composite skeleton offers unique promise as a means for anchoring organophosphonates inside of pores through formation of robust covalent Zr-O-P bonds. PMID:22248432

  4. Hierarchical TiO2/C nanocomposite monoliths with a robust scaffolding architecture, mesopore-macropore network and TiO2-C heterostructure for high-performance lithium ion batteries

    NASA Astrophysics Data System (ADS)

    Huang, Hai-Bo; Yang, Yue; Chen, Li-Hua; Wang, Yun; Huang, Shao-Zhuan; Tao, Jia-Wei; Ma, Xiao-Ting; Hasan, Tawfique; Li, Yu; Xu, Yan; Su, Bao-Lian

    2016-05-01

    Engineering hierarchical structures of electrode materials is a powerful strategy for optimizing the electrochemical performance of an anode material for lithium-ion batteries (LIBs). Herein, we report the fabrication of hierarchical TiO2/C nanocomposite monoliths by mediated mineralization and carbonization using bacterial cellulose (BC) as a scaffolding template as well as a carbon source. TiO2/C has a robust scaffolding architecture, a mesopore-macropore network and TiO2-C heterostructure. TiO2/C-500, obtained by calcination at 500 °C in nitrogen, contains an anatase TiO2-C heterostructure with a specific surface area of 66.5 m2 g-1. When evaluated as an anode material at 0.5 C, TiO2/C-500 exhibits a high and reversible lithium storage capacity of 188 mA h g-1, an excellent initial capacity of 283 mA h g-1, a long cycle life with a 94% coulombic efficiency preserved after 200 cycles, and a very low charge transfer resistance. The superior electrochemical performance of TiO2/C-500 is attributed to the synergistic effect of high electrical conductivity, anatase TiO2-C heterostructure, mesopore-macropore network and robust scaffolding architecture. The current material strategy affords a general approach for the design of complex inorganic nanocomposites with structural stability, and tunable and interconnected hierarchical porosity that may lead to the next generation of electrochemical supercapacitors with high energy efficiency and superior power density.Engineering hierarchical structures of electrode materials is a powerful strategy for optimizing the electrochemical performance of an anode material for lithium-ion batteries (LIBs). Herein, we report the fabrication of hierarchical TiO2/C nanocomposite monoliths by mediated mineralization and carbonization using bacterial cellulose (BC) as a scaffolding template as well as a carbon source. TiO2/C has a robust scaffolding architecture, a mesopore-macropore network and TiO2-C heterostructure. TiO2/C-500

  5. Sample Desorption/Onization From Mesoporous Silica

    DOEpatents

    Iyer, Srinivas; Dattelbaum, Andrew M.

    2005-10-25

    Mesoporous silica is shown to be a sample holder for laser desorption/ionization of mass spectrometry. Supported mesoporous silica was prepared by coating an ethanolic silicate solution having a removable surfactant onto a substrate to produce a self-assembled, ordered, nanocomposite silica thin film. The surfactant was chosen to provide a desired pore size between about 1 nanometer diameter and 50 nanometers diameter. Removal of the surfactant resulted in a mesoporous silica thin film on the substrate. Samples having a molecular weight below 1000, such as C.sub.60 and tryptophan, were adsorbed onto and into the mesoporous silica thin film sample holder and analyzed using laser desorption/ionization mass spectrometry.

  6. A Magnetically Separable, Highly Stable Enzyme System Based on Nanocomposites of Enzymes and Magnetic Nanoparticles Shipped in Hierarchically Ordered, Mesocellular, Mesoporous Silica

    SciTech Connect

    Kim, Jungbae; Lee, Jinwoo; Na, Hyon Bin; Kim, Byoung Chan; Youn, Jongkyu; Kwak, Ja Hun; Moon, Karam; Lee, Eunwoong; Kim, Jaeyun; Park, Jongnam; Dohnalkova, Alice; Park, Hyun-Gyu; Gu, Man Bock; Chang, Ho Nam; Grate, Jay W.; Hyeon, Taeghwan

    2005-12-01

    Enzymes are versatile nanoscale biocatalysts, and find increasing applications in many areas, including organic synthesis[1-3] and bioremediation.[4-5] However, the application of enzymes is often hampered by the short catalytic lifetime of enzymes and by the difficulty in recovery and recycling. To solve these problems, there have been a lot of efforts to develop effective enzyme immobilization techniques. Recent advances in nanotechnology provide more diverse materials and approaches for enzyme immobilization. For example, mesoporous materials offer potential advantages as a host of enzymes due to their well-controlled porosity and large surface area for the immobilization of enzymes.[6,7] On the other hand, it has been demonstrated that enzymes attached on magnetic iron oxide nanoparticles can be easily recovered using a magnet and recycled for iterative uses.[8] In this paper, we report the development of magnetically-separable and highly-stable enzyme system by the combined use of two different kinds of nanostructured materials: magnetic nanoparticles and mesoporous silica.

  7. Two-dimensional magnetic WS2@Fe3O4 nanocomposite with mesoporous silica coating for drug delivery and imaging-guided therapy of cancer.

    PubMed

    Yang, Guangbao; Gong, Hua; Liu, Teng; Sun, Xiaoqi; Cheng, Liang; Liu, Zhuang

    2015-08-01

    Integrating multiple imaging and therapy functionalities into one single nanoscale platform has been proposed to be a promising strategy in cancer theranostics. In this work, WS2 nanosheets with their surface pre-adsorbed with iron oxide (IO) nanoparticles via self-assembly are coated with a mesoporous silica shell, on to which polyethylene glycol (PEG) is attached. The obtained WS2-IO@MS-PEG composite nanoparticles exhibit many interesting inherent physical properties, including high near-infrared (NIR) light and X-ray absorbance, as well as strong superparamagnetism. In the mean time, the mesoporous silica shell in WS2-IO@MS-PEG could be loaded with a chemotherapy drug, doxorubicin (DOX), whose intracellular release afterwards may be triggered by NIR-induced photothermal heating for enhanced cancer cell killing. Upon systemic administration of such drug-loaded nano-theranostics, efficient tumor homing of WS2-IO@MS-PEG/DOX is observed in tumor-bearing mice as revealed by three-modal fluorescence, magnetic resonance (MR), and X-ray computed tomography (CT) imaging. In vivo combined photothermal & chemotherapy is then carried out with WS2-IO@MS-PEG/DOX, achieving a remarkably synergistic therapeutic effect superior to the respective mono-therapies. Our study highlights the promise of developing multifunctional nanoscale theranostics based on two-dimensional transition metal dichalcogenides (TMDCs) such as WS2 for multimodal imaging-guided combination therapy of cancer. PMID:25985153

  8. Preparation and characterization of magnetic nanocomposite of Schiff base/silica/magnetite as a preconcentration phase for the trace determination of heavy metal ions in water, food and biological samples using atomic absorption spectrometry.

    PubMed

    Bagheri, Hasan; Afkhami, Abbas; Saber-Tehrani, Mohammad; Khoshsafar, Hosein

    2012-08-15

    A versatile and robust solid phase with both magnetic property and a very high adsorption capacity is presented on the basis of modification of iron oxide-silica magnetic particles with a newly synthesized Schiff base (Fe(3)O(4)/SiO(2)/L). The structure of the resulting product was confirmed by Fourier transform infrared (FT-IR) spectra, X-ray diffraction (XRD) spectrometry and transmission electron microscopy (TEM). We developed an efficient and cost-effective method for the preconcentration of trace amounts of Pb(II), Cd(II) and Cu(II) in environmental and biological samples using this novel magnetic solid phase. Prepared magnetic solid phase is an ideal support because it has a large surface area, good selectivity and can be easily retrieved from large volumes of aqueous solutions. The possible parameters affecting the enrichment were optimized. Under the optimal conditions, the method detection limit was 0.14, 0.19 and 0.12 μg L(-1) for Pb(II), Cd(II) and Cu(II) ions, respectively. The established method has been successfully applied to analyze real samples, and satisfactory results were obtained. All these indicated that this magnetic phase had a great potential in environmental and biological fields. PMID:22841051

  9. Aptamer/Graphene Quantum Dots Nanocomposite Capped Fluorescent Mesoporous Silica Nanoparticles for Intracellular Drug Delivery and Real-Time Monitoring of Drug Release.

    PubMed

    Zheng, Fen-Fen; Zhang, Peng-Hui; Xi, Yu; Chen, Jing-Jia; Li, Ling-Ling; Zhu, Jun-Jie

    2015-12-01

    Great challenges in investigating the release of drug in complex cellular microenvironments necessitate the development of stimuli-responsive drug delivery systems with real-time monitoring capability. In this work, a smart drug nanocarrier based on fluorescence resonance energy transfer (FRET) is fabricated by capping graphene quantum dots (GQDs, the acceptor) onto fluorescent mesoporous silica nanoparticles (FMSNs, the donor) via ATP aptamer for real-time monitoring of ATP-triggered drug release. Under extracellular conditions, the fluorescence of FMSNs remains in the "off" state in the low ATP level which is unable to trigger the release of drug. Once specifically recognized and internalized into the target tumor cells by AS1411 aptamer, in the ATP-rich cytoplasm, the conformation switch of the ATP aptamer causes the shedding of the GQDs from the nanocarriers, leading to the release of the loaded drugs and consequently severe cytotoxicity. Simultaneously, the fluorescence of FMSNs turns "on" along with the dissociation of GQDs, which allows real-time monitoring of the release of drug from the pores. Such a drug delivery system features high specificity of dual-target recognition with AS1411 and ATP aptamer as well as high sensitivity of the FRET-based monitoring strategy. Thus, the proposed multifunctional ATP triggered FRET-nanocarriers will find potential applications for versatile drug-release monitoring, efficient drug transport, and targeted cancer therapeutics. PMID:26524192

  10. Phosphotungstic acid anchored to amino-functionalized core-shell magnetic mesoporous silica microspheres: a magnetically recoverable nanocomposite with enhanced photocatalytic activity.

    PubMed

    Zhao, Liang; Chi, Yue; Yuan, Qing; Li, Nan; Yan, Wenfu; Li, Xiaotian

    2013-01-15

    H(3)PW(12)O(40) was successfully anchored to the surface of amino-functionalized Fe(3)O(4)@SiO(2)@meso-SiO(2) microspheres by means of chemical bonding to aminosilane groups, aiming to remove unwanted organic compounds from aqueous media. The resultant multifunctional microspheres were thoroughly characterized by transmission electron microscopy, scanning electron microscopy, X-ray diffraction, infrared spectroscopy, inductively coupled plasma, and N(2) adsorption-desorption. The as-prepared microspheres possess unique properties including high magnetization (46.8 emu g(-1)), large BET surface area (135 m(2) g(-1)), and highly open mesopores (~5.0 nm), and H(3)PW(12)O(40) loading is calculated to be ~16.8%; and as a result, the as-prepared microspheres exhibit enhanced performance in degrading dyes under UV irradiation compared with pure H(3)PW(12)O(40). Additionally, the photocatalyst can be easily recycled using an external magnetic field without losing the photocatalytic activity. PMID:23083769

  11. Solid phase extraction of Cu2+, Ni2+, and Co2+ ions by a new magnetic nano-composite: excellent reactivity combined with facile extraction and determination.

    PubMed

    Azizi, Parastou; Golshekan, Mostafa; Shariati, Shahab; Rahchamani, Jalal

    2015-04-01

    In the present study, silica magnetite mesoporous nanoparticles functionalized with a new chelating agent were synthesized and introduced as a magnetic solid phase for preconcentration of trace amounts of Cu2+, Ni2+, and Co2+ ions from aqueous solutions. Briefly, MCM-41 mesoporous-coated magnetite nano-particles (MMNPs) with particle size lower than 15 nm were synthesized via chemical co-precipitation methods. Then, N-(4-methoxysalicylidene)-4,5-dinitro-1,2-phenylenediamine (HL) as a new chelating agent was synthesized and used for surface modification of mesoporous magnetic solid phase by dispersive liquid-liquid functionalization (DLLF) as a new rapid method to form HL functionalized mesoporous magnetite nanoparticles (MMNPs─HL). The structure and morphology of prepared sorbent were characterized by FT-IR, XRD, VSM, and TEM. Finally, the prepared nanoparticles were utilized for preconcentration of Cu2+, Ni2+, and Co2+ ions prior to determination by atomic absorption spectrophotometery. The calibration graph was obtained under the optimized conditions with linear dynamic range of 1.0-300 μg L(-1) and correlation coefficient (r2) of 0.998. The detection limits of this method for cobalt, nickel, and copper ions were 0.03, 0.03, and 0.04 ng/mL, respectively. Finally, the method was successfully applied to the extraction and determination of the analyte ions in natural waters and reference plant samples. PMID:25784609

  12. Mesoporous carbon materials

    DOEpatents

    Dai, Sheng; Fulvio, Pasquale Fernando; Mayes, Richard T.; Wang, Xiqing; Sun, Xiao-Guang; Guo, Bingkun

    2014-09-09

    A conductive mesoporous carbon composite comprising conductive carbon nanoparticles contained within a mesoporous carbon matrix, wherein the conductive mesoporous carbon composite possesses at least a portion of mesopores having a pore size of at least 10 nm and up to 50 nm, and wherein the mesopores are either within the mesoporous carbon matrix, or are spacings delineated by surfaces of said conductive carbon nanoparticles when said conductive carbon nanoparticles are fused with each other, or both. Methods for producing the above-described composite, devices incorporating them (e.g., lithium batteries), and methods of using them, are also described.

  13. Multifunctional mesoporous silica catalyst

    DOEpatents

    Lin, Victor Shang-Yi; Tsai, Chih-Hsiang; Chen, Hung-Ting; Pruski, Marek; Kobayashi, Takeshi

    2015-03-31

    The present invention provides bifunctional silica mesoporous materials, including mesoporous silica nanoparticles ("MSN"), having pores modified with diarylammonium triflate and perfluoroaryl moieties, that are useful for the acid-catalyzed esterification of organic acids with organic alcohols.

  14. Synthesis of mesoporous silica nanoparticles.

    PubMed

    Wu, Si-Han; Mou, Chung-Yuan; Lin, Hong-Ping

    2013-05-01

    Good control of the morphology, particle size, uniformity and dispersity of mesoporous silica nanoparticles (MSNs) is of increasing importance to their use in catalyst, adsorption, polymer filler, optical devices, bio-imaging, drug delivery, and biomedical applications. This review discusses different synthesis methodologies to prepare well-dispersed MSNs and hollow silica nanoparticles (HSNs) with tunable dimensions ranging from a few to hundreds of nanometers of different mesostructures. The methods include fast self-assembly, soft and hard templating, a modified Stöber method, dissolving-reconstruction and modified aerogel approaches. In practical applications, the MSNs prepared by these methods demonstrate good potential for use in high-performance catalysis, antireflection coating, transparent polymer-MSNs nanocomposites, drug-release and theranostic systems. PMID:23403864

  15. Soft-Templated Mesoporous Carbon-Carbon Nanotube Composites for High Performance Lithium-ion Batteries

    SciTech Connect

    Guo, Bingkun; Wang, Xiqing; Fulvio, Pasquale F.; Chi, Miaofang; Mahurin, Shannon M.; Sun, Xiao-Guang; Dai, Sheng

    2011-09-13

    Mesoporous carbon with homogeneously dispersed multi-walled carbon nanotubes (MWNTs) are synthesized via a one-step "brick and mortar" soft-templating approach. Nanocomposites exhibit a reversible lithium storage capacity of 900 mA h g⁻¹ and a good rate performance. Such homogeneous nanocomposites are ideal candidates for electric vehicle applications where high power and energy density are primary requirements.

  16. Carbon functionalized mesoporous silica-based gas sensors for indoor volatile organic compounds.

    PubMed

    Liu, Yupu; Chen, Junchen; Li, Wei; Shen, Dengke; Zhao, Yujuan; Pal, Manas; Yu, Haijun; Tu, Bo; Zhao, Dongyuan

    2016-09-01

    Indoor organic gaseous pollution is a global health problem, which seriously threats the health and life of human all over the world. Hence, it is important to fabricate new sensing materials with high sensitivity and efficiency for indoor volatile organic compounds. In this study, a series of ordered mesoporous silica-based nanocomposites with uniform carbon coatings on the internal surface of silica mesopore channels were synthesized through a simple template-carbonization strategy. The obtained mesoporous silica-carbon nanocomposites not only possess ordered mesostructures, high surface areas (up to ∼759m(2)g(-1)), large and tunable pore sizes (2.6-10.2nm), but also have the improved hydrophobicity and anti-interference capability to environmental humidity. The sensing performances of the mesoporous silica-carbon nanocomposites to volatile organic compounds, such as ethylbenzene, methylbenzene, benzene, methanol, acetone, formaldehyde, dichloromethane and tetrahydrofuran, were systematically investigated. The relationships between the sensing performances and their properties, including mesostructures, surface areas, pore sizes, carbon contents and surface hydrophilic/hydrophobic interactions, have been achieved. The mesoporous silica-carbon nanocomposites with hexagonal mesostructure exhibit outstanding performance at room temperature to benzene and acetone with high responses, short response (2-3s) and recovery (16-19s) time, strong anti-interference to environmental humidity, and long-term stability (less than ∼5% loss of the frequency shifts after 42days). Therefore, the obtained mesoporous silica-carbon nanocomposites have a hopeful prospect in the field of environmental air quality monitoring. PMID:27240244

  17. Polyolefin nanocomposites

    DOEpatents

    Chaiko, David J.

    2007-01-02

    The present invention relates to methods for the preparation of clay/polymer nanocomposites. The methods include combining an organophilic clay and a polymer to form a nanocomposite, wherein the organophilic clay and the polymer each have a peak recrystallization temperature, and wherein the organophilic clay peak recrystallization temperature sufficiently matches the polymer peak recrystallization temperature such that the nanocomposite formed has less permeability to a gas than the polymer. Such nanocomposites exhibit 2, 5, 10, or even 100 fold or greater reductions in permeability to, e.g., oxygen, carbon dioxide, or both compared to the polymer. The invention also provides a method of preparing a nanocomposite that includes combining an amorphous organophilic clay and an amorphous polymer, each having a glass transition temperature, wherein the organophilic clay glass transition temperature sufficiently matches the polymer glass transition temperature such that the nanocomposite formed has less permeability to a gas than the polymer.

  18. Application of novel Polypyrrole/thiol-functionalized zeolite Beta/MCM-41 type mesoporous silica nanocomposite for adsorption of Hg2+ from aqueous solution and industrial wastewater: Kinetic, isotherm and thermodynamic studies

    NASA Astrophysics Data System (ADS)

    Javadian, Hamedreza; Taghavi, Mehdi

    2014-01-01

    Hierarchical zeolite consists of both microporous and unordered mesoporous structures. A composite of Polypyrrole/thiol-functionalized Beta/MCM-41 (PPy/SH-Beta/MCM-41) was prepared, characterized by FE-SEM, FT-IR, XRD, TGA and BET analysis and applied in the investigation of its adsorption characteristics for the removal of Hg2+ ions from aqueous solutions. Thiol-functionalized Beta/MCM-41 (SH-Beta/MCM-41) was prepared by 3-mercaptopropyltrimethoxysilane (MPTMS) in the presence of aerosil-200 as a silica source by two-step hydrothermal crystallization procedure. Batch mode experiments were conducted and three kinetic models were used to describe the adsorption process. The experimental data fitted very well with the Pseudo-second-order kinetic model. The calculated thermodynamic parameters (ΔH, ΔS and ΔG) revealed that the adsorption of Hg2+ onto PPy/SH-Beta/MCM-41 is an endothermic and spontaneous process. It was found that temperature has a positive effect on the removal efficiency and that PPy/SH-Beta/MCM-41 is potentially able to remove Hg2+ ions from aqueous solutions at even high concentrations (400 mg L-1). The recovery of Hg2+ from the PPy/SH-Beta/MCM-41 adsorbent was found to be more than 90% using 0.5 M H2SO4, and the ability of the absorbent to be reused for removal of Hg2+ was investigated.

  19. Surface-functionalized mesoporous carbon materials

    DOEpatents

    Dai, Sheng; Gorka, Joanna; Mayes, Richard T.

    2016-02-02

    A functionalized mesoporous carbon composition comprising a mesoporous carbon scaffold having mesopores in which polyvinyl polymer grafts are covalently attached, wherein said mesopores have a size of at least 2 nm and up to 50 nm. Also described is a method for producing the functionalized mesoporous composition, wherein a reaction medium comprising a precursor mesoporous carbon, vinyl monomer, initiator, and solvent is subjected to sonication of sufficient power to result in grafting and polymerization of the vinyl monomer into mesopores of the precursor mesoporous carbon. Also described are methods for using the functionalized mesoporous carbon, particularly in extracting metal ions from metal-containing solutions.

  20. Mesoporous carbon materials

    SciTech Connect

    Dai, Sheng; Wang, Xiqing

    2012-02-14

    The invention is directed to a method for fabricating a mesoporous carbon material, the method comprising subjecting a precursor composition to a curing step followed by a carbonization step, the precursor composition comprising: (i) a templating component comprised of a block copolymer, (ii) a phenolic compound or material, (iii) a crosslinkable aldehyde component, and (iv) at least 0.5 M concentration of a strong acid having a pKa of or less than -2, wherein said carbonization step comprises heating the precursor composition at a carbonizing temperature for sufficient time to convert the precursor composition to a mesoporous carbon material. The invention is also directed to a mesoporous carbon material having an improved thermal stability, preferably produced according to the above method.

  1. Mesoporous carbon materials

    DOEpatents

    Dai, Sheng; Wang, Xiqing

    2013-08-20

    The invention is directed to a method for fabricating a mesoporous carbon material, the method comprising subjecting a precursor composition to a curing step followed by a carbonization step, the precursor composition comprising: (i) a templating component comprised of a block copolymer, (ii) a phenolic compound or material, (iii) a crosslinkable aldehyde component, and (iv) at least 0.5 M concentration of a strong acid having a pKa of or less than -2, wherein said carbonization step comprises heating the precursor composition at a carbonizing temperature for sufficient time to convert the precursor composition to a mesoporous carbon material. The invention is also directed to a mesoporous carbon material having an improved thermal stability, preferably produced according to the above method.

  2. Periodic Mesoporous Organosilica Nanorice

    NASA Astrophysics Data System (ADS)

    Mohanty, Paritosh; Landskron, Kai

    2009-02-01

    A periodic mesoporous organosilica (PMO) with nanorice morphology was successfully synthesized by a template assisted sol-gel method using a chain-type precursor. The PMO is composed of D and T sites in the ratio 1:2. The obtained mesoporous nanorice has a surface area of 753 m2 g-1, one-dimensional channels, and a narrow pore size distribution centered at 4.3 nm. The nanorice particles have a length of ca. 600 nm and width of ca. 200 nm.

  3. Anisotropic growth-induced synthesis of dual-compartment Janus mesoporous silica nanoparticles for bimodal triggered drugs delivery.

    PubMed

    Li, Xiaomin; Zhou, Lei; Wei, Yong; El-Toni, Ahmed Mohamed; Zhang, Fan; Zhao, Dongyuan

    2014-10-22

    Multifunctional dual-compartment Janus mesoporous silica nanocomposites of UCNP@SiO2@mSiO2&PMO (UCNP = upconversion nanoparticle, PMO = periodic mesoporous organosilica) containing core@shell@shell structured UCNP@SiO2@mSiO2 nanospheres and PMO single-crystal nanocubes have been successfully synthesized via a novel anisotropic island nucleation and growth approach with the ordered mesostructure. The asymmetric Janus nanocomposites show a very uniform size of ~300 nm and high surface area of ~1290 m(2)/g. Most importantly, the Janus nanocomposites possess the unique dual independent mesopores with different pore sizes (2.1 nm and 3.5-5.5 nm) and hydrophobicity/hydrophilicity for loading of multiple guests. The distinct chemical properties of the silica sources and the different mesostructures of the dual-compartments are the necessary prerequisites for the formation of the Janus nanostructure. With the assistance of the near-infrared (NIR) to ultraviolet/visible (UV-vis) optical properties of UCNPs and heat-sensitive phase change materials, the dual-compartment Janus mesoporous silica nanocomposites can be further applied into nanobiomedicine for heat and NIR light bimodal-triggered dual-drugs controllable release. It realizes significantly higher efficiency for cancer cell killing (more than 50%) compared to that of the single-triggered drugs delivery system (~25%). PMID:25251874

  4. Biocatalytic approach for polymer synthesis and polymer encapsulation in mesoporous materials

    NASA Astrophysics Data System (ADS)

    Ford, Christy

    The goal of this research is to encapsulate enzymatically synthesized polymers within the pores of mesoporous silica. In order to fully understand the effect of polymer incorporation on mesoporous silica structure, the effect of dopant and polymer on micelle shape, the effect of dopant on the final mesoporous silica structure, and the effect of incorporating polymer within mesoporous silica are investigated. Direct entrapment of aromatic molecules within cationic micelles to ultimately fabricate tailored, functional mesoporous silica/polymer composites is investigated. Specifically, the influence of 4-ethylphenol and aniline on the shape of cetyltrimethylammonium bromide (CTAB) micelles and on the structure of mesoporous silica synthesized via the micellar templating is investigated. Small angle neutron scattering indicates that the dopant affects the micellar size, micellar arrangement, and the domain size over which the arrangement extends. Cryo-TEM offers further insight into the micellar shape. The effect of the dopant-to-surfactant molar ratio on the structure of surfactant-templated mesoporous silica is characterized by x-ray diffraction, transmission electron microscopy, and nitrogen sorption techniques. The mesoporous silica undergoes a transition from hexagonal to lamellar with increasing dopant-to-surfactant molar ratio for both 4-ethylphenol and 2-naphthol, suggesting a possible change in the template morphology. A better understanding of the relation between dopant, micellar shape, and mesoporous structure plays a critical role in the development of polymer-ceramic nanocomposites with novel electrooptical, conductive, and fluorescent properties. A novel method for encapsulating polymers in mesoporous silica is presented. The method involves enzymatic synthesis of polyphenols and polyaromatic amines in micellar aggregates, and subsequently condensing silica at the surfactant-water interface. Thus, poly(4-ethylphenol), poly(2-naphthol), and polyaniline

  5. Tailoring the mesoporous texture of graphitic carbon nitride.

    PubMed

    Yang, Jae-Hun; Kim, Gain; Domen, Kazunari; Choy, Jin-Ho

    2013-11-01

    Recently, graphitic carbon nitride (g-C3N4) materials have received a great attention from many researchers due to their various roles as a visible light harvesting photocatalyst, metal-free catalyst, reactive template, nitrogen source of nitridation reaction, etc. g-C3N4 could be prepared by temperature-induced polymerization of cyanamide or melamine. In this study, we report a preparation of mesoporous graphitic carbon nitrides with tailored porous texture including pore size, and specific surface area from cyanamide and colloidal silica nanoparticles (Ludox). At first, cyanamide-silica nanocomposites were prepared by mixing colloidal silica with different size in the range of 7-22 nm and cyanamide, followed by evaporating the solvent in the resulting mixture. Mesoporous g-C3N4 samples were prepared by calcining cyanamide-silica nanocomposite at 550 degrees C for 4 hrs and removing the silica nanoparticles by using ammonium hydrogen fluoride. The formation of g-C3N4 was confirmed by the sharp (002) peak (d = 3.25 A) of graphitic interlayer stacking, and the broad (100) peak (d = 6.86 A) of in-plane repeating unit in the X-ray diffraction patterns. According to N2 adsorption-desorption analysis, the pore size of mesoporous carbon nitrides was similar to the size of colloidal silica used as hard template (7-22 nm). The specific surface area of mesoporous g-C3N4 could be tailored in the range of 189 m2/g-288 m2/g. PMID:24245279

  6. Mesoporous carbons and polymers

    DOEpatents

    Bell, William; Dietz, Steven

    2001-01-01

    A mesoporous material prepared by polymerizing a resorcinol/formaldehyde system from an aqueous solution containing resorcinol, formaldehyde and a surfactant and optionally pyrolyzing the polymer to form a primarily carbonaceous solid. The material has an average pore size between 4 and 75 nm and is suitable for use in liquid-phase surface limited applications, including sorbent, catalytic, and electrical applications.

  7. Two-Solvent Method Synthesis of NiO/ZnO Nanoparticles Embedded in Mesoporous SBA-15: Photocatalytic Properties Study

    NASA Astrophysics Data System (ADS)

    Dai, Peng; Yan, Tao-tao; Yu, Xin-xin; Bai, Zhi-man; Wu, Ming-zai

    2016-04-01

    Different loadings of NiO/ZnO nanoparticles embedded in mesoporous silica (SBA-15) were prepared via a two-solvent method with the ordered hexagonal mesoporous structure of SBA-15 kept. X-ray diffraction, transmission electron microscope, X-ray photoelectron spectroscopy, diffusive reflective UV-vis spectroscopy, and N2 adsorption porosimetry were employed to characterize the nanocomposites. The results indicate that the ordered hexagonal mesoporous structure of SBA-15 is kept and the absorption band edges of the nanocomposites shift into the ultraviolet light regime. The photocatalytic activity of our samples for degradation of methylene orange was investigated under UV light irradiation, and the results show that the nanocomposites have higher photodegradation ability toward methylene orange than commercial pure P-25. The photocatalytic activity of the nanocomposites was found to be dependent on both the adsorption ability of the SBA-15 and the photocatalytic activity of NiO-ZnO nanoparticles encapsulated in SBA-15. In addition, there is an optimal loading of NiO-ZnO nanoparticles. Too high or low loading will lower the photodegradation ability of the nanocomposites.

  8. Two-Solvent Method Synthesis of NiO/ZnO Nanoparticles Embedded in Mesoporous SBA-15: Photocatalytic Properties Study.

    PubMed

    Dai, Peng; Yan, Tao-Tao; Yu, Xin-Xin; Bai, Zhi-Man; Wu, Ming-Zai

    2016-12-01

    Different loadings of NiO/ZnO nanoparticles embedded in mesoporous silica (SBA-15) were prepared via a two-solvent method with the ordered hexagonal mesoporous structure of SBA-15 kept. X-ray diffraction, transmission electron microscope, X-ray photoelectron spectroscopy, diffusive reflective UV-vis spectroscopy, and N2 adsorption porosimetry were employed to characterize the nanocomposites. The results indicate that the ordered hexagonal mesoporous structure of SBA-15 is kept and the absorption band edges of the nanocomposites shift into the ultraviolet light regime. The photocatalytic activity of our samples for degradation of methylene orange was investigated under UV light irradiation, and the results show that the nanocomposites have higher photodegradation ability toward methylene orange than commercial pure P-25. The photocatalytic activity of the nanocomposites was found to be dependent on both the adsorption ability of the SBA-15 and the photocatalytic activity of NiO-ZnO nanoparticles encapsulated in SBA-15. In addition, there is an optimal loading of NiO-ZnO nanoparticles. Too high or low loading will lower the photodegradation ability of the nanocomposites. PMID:27119154

  9. Mesoporous aluminum phosphite

    SciTech Connect

    El Haskouri, Jamal; Perez-Cabero, Monica; Guillem, Carmen; Latorre, Julio; Beltran, Aurelio; Beltran, Daniel; Amoros, Pedro

    2009-08-15

    High surface area pure mesoporous aluminum-phosphorus oxide-based derivatives have been synthesized through an S{sup +}I{sup -} surfactant-assisted cooperative mechanism by means of a one-pot preparative procedure from aqueous solution and starting from aluminum atrane complexes and phosphoric and/or phosphorous acids. A soft chemical extraction procedure allows opening the pore system of the parent as-prepared materials by exchanging the surfactant without mesostructure collapse. The nature of the pore wall can be modulated from mesoporous aluminum phosphate (ALPO) up to total incorporation of phosphite entities (mesoporous aluminum phosphite), which results in a gradual evolution of the acidic properties of the final materials. While phosphate groups in ALPO act as network building blocks (bridging Al atoms), the phosphite entities become basically attached to the pore surface, what gives practically empty channels. The mesoporous nature of the final materials is confirmed by X-ray diffraction (XRD), transmission electron microscopy (TEM) and N{sub 2} adsorption-desorption isotherms. The materials present regular unimodal pore systems whose order decreases as the phosphite content increases. NMR spectroscopic results confirm the incorporation of oxo-phosphorus entities to the framework of these materials and also provide us useful information concerning the mechanism through which they are formed. - Abstract: TEM image of the mesoporous aluminum phosphite showing the hexagonal disordered pore array that is generated by using surfactant micelles as template. Also a scheme emphasizing the presence of an alumina-rich core and an ALPO-like pore surface is presented.

  10. Advanced Mesoporous Spinel Li4Ti5O12/rGO Composites with Increased Surface Lithium Storage Capability for High-Power Lithium-Ion Batteries.

    PubMed

    Ge, Hao; Hao, Tingting; Osgood, Hannah; Zhang, Bing; Chen, Li; Cui, Luxia; Song, Xi-Ming; Ogoke, Ogechi; Wu, Gang

    2016-04-13

    Spinel Li4Ti5O12 (LTO) and reduced graphene oxide (rGO) are attractive anode materials for lithium-ion batteries (LIBs) because of their unique electrochemical properties. Herein, we report a facile one-step hydrothermal method in preparation of a nanocomposite anode consisting of well-dispersed mesoporous LTO particles onto rGO. An important reaction step involves glucose as a novel linker agent and reducing agent during the synthesis. It was found to prevent the aggregation of LTO particles, and to yield mesoporous structures in nanocomposites. Moreover, GO is reduced to rGO by the hydroxyl groups on glucose during the hydrothermal process. When compared to previously reported LTO/graphene electrodes, the newly prepared LTO/rGO nanocomposite has mesoporous characteristics and provides additional surface lithium storage capability, superior to traditional LTO-based materials for LIBs. These unique properties lead to markedly improved electrochemical performance. In particular, the nanocomposite anode delivers an ultrahigh reversible capacity of 193 mA h g(-1) at 0.5 C and superior rate performance capable of retaining a capacity of 168 mA h g(-1) at 30 C between 1.0 and 2.5 V. Therefore, the newly prepared mesoporous LTO/rGO nanocomposite with increased surface lithium storage capability will provide a new opportunity to develop high-power anode materials for LIBs. PMID:27015357

  11. Highly sensitive and stable relative humidity sensors based on WO3 modified mesoporous silica

    NASA Astrophysics Data System (ADS)

    Tomer, Vijay K.; Duhan, Surender

    2015-02-01

    This study investigates the effectiveness of using WO3 loaded mesoporous silica nanocomposite developed using one step hydrothermal method for measuring relative humidity (RH) at room temperature. On measuring the sensing response, the nanocomposite sensor exhibits excellent linearity, negligible hysteresis, swift response and recovery time, good repeatability, and outstanding stability in 11%-98% RH range. The complex impedance spectra of the sensor at different RHs were used to explore the humidity sensing mechanism. This work could encourage a right approach to blueprint practical humidity sensors with high sensitivity, long stability and fast response/recovery time.

  12. Magnetic nanocomposites.

    PubMed

    Behrens, Silke; Appel, Ingo

    2016-06-01

    Magnetic nanocomposites are multi-component materials, typically containing nanosized magnetic materials to trigger the response to an external stimulus (i.e., an external static or alternating magnetic field). Up to now, the search for novel nanocomposites has lead to the combination of a plethora of different materials (e.g., gels, liquid crystals, renewable polymers, silica, carbon or metal organic frameworks) with various types of magnetic particles, offering exciting perspectives not only for fundamental investigations but also for application in various fields, including medical therapy and diagnosis, separations, actuation, or catalysis. In this review, we have selected a few of the most recent examples to highlight general concepts and advances in the preparation of magnetic nanocomposites and recent advances in the synthesis of magnetic nanoparticles. PMID:26938504

  13. Highly Loaded Mesoporous Silica/Nanoparticle Composites and Patterned Mesoporous Silica Films

    NASA Astrophysics Data System (ADS)

    Kothari, Rohit; Hendricks, Nicholas R.; Wang, Xinyu; Watkins, James J.

    2014-03-01

    Novel approaches for the preparation of highly filled mesoporous silica/nanoparticle (MS/NP) composites and for the fabrication of patterned MS films are described. The incorporation of iron platinum NPs within the walls of MS is achieved at high NP loadings by doping amphiphilic poly(ethylene oxide-b-propylene oxide-b-ethylene oxide) (Pluronic®) copolymer templates via selective hydrogen bonding between the pre-synthesized NPs and the hydrophilic portion of the block copolymer. The MS is then synthesized by means of phase selective condensation of tetraethylorthosilicate (TEOS) within the NP loaded block copolymer templates dilated with supercritical carbon dioxide (scCO2) followed by calcination. For patterned films, microphase separated block copolymer/small molecule additive blends are patterned using UV-assisted nanoimprint lithography. Infusion and condensation of a TEOS within template films using ScCO2 as a processing medium followed by calcination yields the patterned MS films. Scanning electron microscopy is used characterize pattern fidelity and transmission electron microscopy analysis confirms the presence of the mesopores. Long range order in nanocomposites is confirmed by low angle x-ray diffraction.

  14. Preparing mesoporous carbon and silica with rosin-silica composite gel.

    PubMed

    Liu, Haidi; Du, Shangfeng; Chen, Yunfa

    2009-02-01

    Mesoporous carbon and mesoporous silica were prepared respectively with a same rosin-silica nanocomposite gel which was synthesized by cogelating tetra-ethyl-oxy-silane (silica source) and rosin (carbon source). Carbonizing the gel in nitrogen and then etching away silica with alkaline solution, mesoporous carbon with specific surface area larger than 800 m2/g was obtained. If calcining the gel at high temperature in air for given time, porous silica with surface area higher than 700 m2/g was done. BET measurement was employed to investigate the pore distribution and surface area of the samples. Most of the pores in both the porous carbon and porous silica were mesoscale, which makes the materials potential in enzyme supports for bio-catalyzed reaction or adsorbents for contaminants with large molecular size. PMID:19441395

  15. A Single-Step Synthesis of Electroactive Mesoporous ProDOT-Silica Structures.

    PubMed

    Kim, Jeonghun; Kim, Byeonggwan; Anand, Chokkalingam; Mano, Ajayan; Zaidi, Javaid S M; Ariga, Katsuhiko; You, Jungmok; Vinu, Ajayan; Kim, Eunkyoung

    2015-07-13

    The single-step preparation of highly ordered mesoporous silica hybrid nanocomposites with conjugated polymers was explored using a novel cationic 3,4-propylenedioxythiophene (ProDOT) surfactant (PrS). The method does not require high-temperature calcination or a washing procedure. The combination of self-assembly of the silica surfactant and in situ polymerization of the ProDOT tail is responsible for creation of the mesoporosity with ultralarge pores, large pore volume, and electroactivity. As this novel material exhibits excellent textural parameters together with electrical conductivity, we believe that this could find potential applications in various fields. This novel concept of creating mesoporosity without a calcination process is a significant breakthrough in the field of mesoporous materials and the method can be further generalized as a rational preparation of various mesoporous hybrid materials having different structures and pore diameters. PMID:26037244

  16. Electrooxidation of formaldehyde based on nickel-palladium modified ordered mesoporous silicon.

    PubMed

    Miao, Fengjuan; Tao, Bairui

    2013-04-01

    Nickel and palladium nanoparticles were finely dispersed on ordered mesoporous silicon microchannels plate (MCP) by electroless plating. The structure and composition of the resulting Ni-Pd/Si MCP were characterized by scanning electron microscopy (SEM) and energy dispersive X-ray spectrometry (EDS). The electrocatalystic properties of Ni-Pd/Si MCP electrode for formaldehyde oxidation have been investigated by cyclic voltammetry. The results show that Ni-Pd/Si MCP has a higher catalytic activity and better steady-state behavior for formaldehyde oxidation. This may be attributed to the synergistic property of high dispersion of Nickel and Palladium nanoparticles and particular properties of mesoporous Si MCP. The present study shows a promising choice of Ni-Pd nanoparticles supported by mesoporous silicon as effective electrocatalyst for formaldehyde electrooxidation in alkaline medium. The results imply that the Ni-Pd/Si MCP nanocomposite has good potential application in formaldehyde fuel cells and sensors. PMID:23763207

  17. A general route to hollow mesoporous rare-earth silicate nanospheres as a catalyst support.

    PubMed

    Jin, Renxi; Yang, Yang; Zou, Yongcun; Liu, Xianchun; Xing, Yan

    2014-02-17

    Hollow mesoporous structures have recently aroused intense research interest owing to their unique structural features. Herein, an effective and precisely controlled synthesis of hollow rare-earth silicate spheres with mesoporous shells is reported for the first time, produced by a simple hydrothermal method, using silica spheres as the silica precursors. The as-prepared hollow rare-earth silicate spheres have large specific surface area, high pore volume, and controllable structure parameters. The results demonstrate that the selection of the chelating reagent plays critical roles in forming the hollow mesoporous structures. In addition, a simple and low-energy-consuming approach to synthesize highly stable and dispersive gold nanoparticle-yttrium silicate (AuNPs/YSiO) hollow nanocomposites has also been developed. The reduction of 4-nitrophenol with AuNPs/YSiO hollow nanocomposites as the catalyst has clearly demonstrated that the hollow rare-earth silicate spheres are good carriers for Au nanoparticles. This strategy can be extended as a general approach to prepare multifunctional yolk-shell structures with diverse compositions and morphologies simply by replacing silica spheres with silica-coated nanocomposites. PMID:24449457

  18. Biomolecule-assisted route to prepare titania mesoporous hollow structures.

    PubMed

    Ding, Shangjun; Wang, Yaoming; Hong, Zhanglian; Lü, Xujie; Wan, Dongyun; Huang, Fuqiang

    2011-10-01

    Amino acids, as a particularly important type of biomolecules, have been used as multifunctional templates to intelligently construct mesoporous TiO(2) hollow structures through a simple solvothermal reaction. The structure-directing behaviors of various amino acids were systematically investigated, and it was found that these biomolecules possess the general capability to assist mesoporous TiO(2) hollow-sphere formation. At the same time, the nanostructures of the obtained TiO(2) are highly dependent on the isoelectric points (pI) of amino acids. Their molecular-structure variations can lead to pI differences and significantly influence the final TiO(2) morphologies. Higher-pI amino acids (e.g., L-lysine and L-arginine) have better structure-directing abilities to generate nanosheet-assembled hollow spheres and yolk/shell structures. The specific morphologies and mesopore size of these novel hollow structures can also be tuned by adjusting the titanium precursor concentration. Heat treatment in air and vacuum was further conducted to transform the as-prepared structures to porous nanoparticle-assembled hollow TiO(2) and TiO(2)/carbon nanocomposites, which may be potentially applied in the fields of photocatalysts, dye-sensitized solar cells, and Li batteries. This study provides some enlightenment on the design of novel templates by taking advantage of biomolecules. PMID:21882272

  19. Mesoporous Few-Layer Graphene Platform for Affinity Biosensing Application.

    PubMed

    Ali, Md Azahar; Singh, Chandan; Mondal, Kunal; Srivastava, Saurabh; Sharma, Ashutosh; Malhotra, Bansi D

    2016-03-30

    A label-free, highly reproducible, sensitive, and selective biosensor is proposed using antiapolipoprotein B 100 (AAB) functionalized mesoporous few-layer reduced graphene oxide and nickel oxide (rGO-NiO) nanocomposite for detection of low density lipoprotein (LDL) molecules. The formation of mesoporous rGO-NiO composite on indium tin oxide conductive electrode has been accomplished via electrophoretic technique using colloidal suspension of rGO sheets and NiO nanoparticles. This biosensor shows good stability obtained by surface conjugation of antibody AAB molecules with rGO-NiO matrix by EDC-NHS coupling chemistry. The defect-less few layer rGO sheets, NiO nanoparticles (nNiO) and formation of nanocomposite has been confirmed by Raman mapping, electron microscopic studies, X-ray diffraction, and electrochemical techniques. The synthesized rGO-NiO composite is mesoporous dominated with a small percentage of micro and macroporous structure as is evident by the results of Brunauer-Emmett-Teller experiment. Further, the bioconjugation of AAB with rGO-NiO has been investigated by Fourier transform-infrared spectroscopy studies. The kinetic studies for binding of antigen-antibody (LDL-AAB) and analytical performance of this biosensor have been evaluated by the impedance spectroscopic method. This biosensor exhibits an excellent sensitivity of 510 Ω (mg/dL)(-1) cm(-2) for detection of LDL molecules and is sensitive to 5 mg/dL concentration of LDL in a wide range of 0-130 mg/dL. Thus, this fabricated biosensor is an efficient and highly sensitive platform for the analysis of other antigen-antibody interactions and biomolecules detection. PMID:26950488

  20. Mesoporous materials for antihydrogen production.

    PubMed

    Consolati, Giovanni; Ferragut, Rafael; Galarneau, Anne; Di Renzo, Francesco; Quasso, Fiorenza

    2013-05-01

    Antimatter is barely known by the chemist community and this article has the vocation to explain how antimatter, in particular antihydrogen, can be obtained, as well as to show how mesoporous materials could be used as a further improvement for the production of antimatter at very low temperatures (below 1 K). The first experiments with mesoporous materials highlighted in this review show very promising and exciting results. Mesoporous materials such as mesoporous silicon, mesoporous material films, pellets of MCM-41 and silica aerogel show remarkable features for antihydrogen formation. Yet, the characteristics for the best future mesoporous materials (e.g. pore sizes, pore connectivity, shape, surface chemistry) remain to be clearly identified. For now among the best candidates are pellets of MCM-41 and aerogel with pore sizes between 10 and 30 nm, possessing hydrophobic patches on their surface to avoid ice formation at low temperature. From a fundamental standpoint, antimatter experiments could help to shed light on open issues, such as the apparent asymmetry between matter and antimatter in our universe and the gravitational behaviour of antimatter. To this purpose, basic studies on antimatter are necessary and a convenient production of antimatter is required. It is exactly where mesoporous materials could be very useful. PMID:23250616

  1. Drug silica nanocomposite: preparation, characterization and skin permeation studies.

    PubMed

    Pilloni, Martina; Ennas, Guido; Casu, Mariano; Fadda, Anna Maria; Frongia, Francesca; Marongiu, Francesca; Sanna, Roberta; Scano, Alessandra; Valenti, Donatella; Sinico, Chiara

    2013-01-01

    The aim of this work was to evaluate silica nanocomposites as topical drug delivery systems for the model drug, caffeine. Preparation, characterization, and skin permeation properties of caffeine-silica nanocomposites are described. Caffeine was loaded into the nanocomposites by grinding the drug with mesoporous silica in a ball mill up to 10 h and the efficiency of the process was studied by XRPD. Formulations were characterized by several methods that include FTIR, XRPD, SEM and TEM. The successful loading of caffeine was demonstrated by XRPD and FTIR. Morphology was studied by SEM that showed particle size reduction while TEM demonstrated formation of both core-shell and multilayered caffeine-silica structures. Solid-state NMR spectra excluded chemical interactions between caffeine and silica matrix, thus confirming that no solid state reactions occurred during the grinding process. Influence of drug inclusion in silica nanocomposite on the in vitro caffeine diffusion into and through the skin was investigated in comparison with a caffeine gel formulation (reference), using newborn pig skin and vertical Franz diffusion cells. Results from the in vitro skin permeation experiments showed that inclusion into the nanocomposite reduced and delayed caffeine permeation from the silica nanocomposite in comparison with the reference, independently from the amount of the tested formulation. PMID:22324371

  2. Mesoporous polyacrylic acid supported silver nanoparticles as an efficient catalyst for reductive coupling of nitrobenzenes and alcohols using glycerol as hydrogen source.

    PubMed

    Mandi, Usha; Roy, Anupam Singha; Kundu, Sudipta K; Roy, Susmita; Bhaumik, Asim; Islam, Sk Manirul

    2016-06-15

    Silver nanoparticle immobilized mesoporous cross-linked polyacrylic acid (Ag-MCP-1) has been synthesized via aqueous-phase polymerization of acrylic acid followed by the surface immobilization with silver nanoparticles. The nanocomposite material has been characterized by different spectroscopic techniques. Powder X-ray diffraction patterns revealed the formation of silver nanoparticles, while transmission electron microscope image showed that Ag nanoparticles are formed and uniformly dispersed in the mesoporous polyacrylic acid. The Ag-MCP-1 nanocomposite can be used as an efficient heterogeneous catalyst in the reductive coupling of nitrobenzenes and alcohols using glycerol as hydrogen source. This nanocomposite can be reused more than five times without any significant decrease in its catalytic activity. PMID:27038284

  3. Preparation and photoluminescence of monolithic silica glass doped with Tb3+ ions using SiO2-PVA nanocomposite

    NASA Astrophysics Data System (ADS)

    Ikeda, Hiroshi; Murata, Takahiro; Fujino, Shigeru

    2014-05-01

    The monolithic silica glass doped with Tb3+ ions was fabricated using the SiO2-PVA nanocomposite as the glass precursor. In order to dope Tb3+ ions in the monolithic silica glass, the mesoporous SiO2-PVA nanocomposite was immersed in the Tb3+ ions contained solution and subsequently sintered at 1100 °C in air. Consequently the monolithic transparent silica glass was obtained, exhibiting green fluorescence attributed to 5D4 → 7F5 main transitions under UV excitation. The Tb concentration in the sintered glass could be controlled by immersion time of the nanocomposite in the solution.

  4. One-pot synthesis of silicon nanoparticles trapped in ordered mesoporous carbon for use as an anode material in lithium-ion batteries

    NASA Astrophysics Data System (ADS)

    Park, Junsu; Kim, Gil-Pyo; Nam, Inho; Park, Soomin; Yi, Jongheop

    2013-01-01

    Silicon nanoparticles trapped in an ordered mesoporous carbon composite were prepared by a one-step self-assembly with solvent evaporation using the triblock copolymer Pluronic F127 and a resorcinol-formaldehyde polymer as the templating agent and carbon precursor respectively. Such a one-pot synthesis of Si/ordered mesoporous carbon nanocomposite is suitable for large-scale synthesis. Characterization confirmed that the Si nanoparticles were trapped in the ordered mesoporous carbon, as evidenced by transmission electron microscopy, x-ray diffraction analysis and nitrogen sorption isotherms. The composite showed a high reversible capacity above 700 mA h g-1 during 50 cycles at 2 A g-1. The improved electrochemical performance of the composite can be ascribed to the buffering effect of spaces formed in the ordered pore channels during the volume expansion of silicon and the rapid movement of lithium ions through the uniform cylindrical pore structure of the mesopores.

  5. Engineered monodisperse mesoporous materials

    SciTech Connect

    Saunders, R.S.; Small, J.H.; Lagasse, R.R.; Schroeder, J.L.; Jamison, G.M.

    1997-08-01

    Porous materials technology has developed products with a wide variety of pore sizes ranging from 1 angstrom to 100`s of microns and beyond. Beyond 15{angstrom} it becomes difficult to obtain well ordered, monodisperse pores. In this report the authors describe efforts in making novel porous material having monodisperse, controllable pore sizes spanning the mesoporous range (20--500 {angstrom}). They set forth to achieve this by using unique properties associated with block copolymers--two linear homopolymers attached at their ends. Block copolymers phase separate into monodisperse mesophases. They desired to selectively remove one of the phases and leave the other behind, giving the uniform monodisperse pores. To try to achieve this the authors used ring-opening metathesis polymerization to make the block copolymers. They synthesized a wide variety of monomers and surveyed their polymers by TGA, with the idea that one phase could be made thermally labile while the other phase would be thermally stable. In the precipitated and sol-gel processed materials, they determined by porosimetry measurements that micropores, mesopores, and macropores were created. In the film processed sample there was not much porosity present. They moved to a new system that required much lower thermal treatments to thermally remove over 90% of the labile phase. Film casting followed by thermal treatment and solvent extraction produced the desired monodisperse materials (based solely on SEM results). Modeling using Density Functional Theory was also incorporated into this project. The modeling was able to predict accurately the domain size and spacing vs. molecular weight for a model system, as well as accurate interfacial thicknesses.

  6. Interactions of Plutonium and Lanthanides with Ordered Mesoporous Materials

    NASA Astrophysics Data System (ADS)

    Parsons-Moss, Tashi

    Pu(IV), Pu(VI), Eu(III), Ce(III), and Zr(IV). The acetamide phosphonate functionalized silica called Ac-Phos-SBA-15 required more extensive synthesis than the other three functionalized silica materials. Development of functionalized mesoporous silica extractants for actinides is contingent on their synthesis and hydrolytic stability, and these two aspects of the Ac-Phos-SBA-15 material are discussed. This material showed the highest binding affinity for all of the target ions, and the sorption and desorption of Pu(VI) to Ac-Phos-SBA-15 was extensively investigated. Ordered mesoporous carbons are attractive as sorbents because of their extremely high surface areas and large pore volumes, and could be suitable substrates for the development of actinide sensors based on their electrochemical properties. Three different mesoporous carbon materials were synthesized by collaborators to test their application as radionuclide sorbent materials. The first is called CMK (carbons mesostructured by Korea Advanced Institute of Science and Technology), and was synthesized using a hard silica template with 3D-bicontinuous ordered mesostructure. Highly ordered body-centered cubic mesoporous carbon was synthesized by self-assembly of a phenol resin around a soft polymer template, and this material is known as FDU-16 (Fudan University). Etching of the silica portion of mesoporous carbon-silica composites created the 2D-hexagonal mesoporous carbon called C-CS (carbon from carbon-silica nanocomposites) with a bimodal pore size distribution. The as-synthesized nanocast mesoporous carbon in this work is called UN CMK, and the same material after oxidation treatment with nitric acid is called OX CMK. A portion of both FDU-16-type and C-CS-type ordered mesoporous carbons were oxidized with acidic ammonium persulfate, which created the oxidized carbon materials called FDU-16-COOH and C-CS-COOH, respectively. The mesoporous carbons were characterized by scanning electron microscopy to view

  7. Facile Fabrication of Well-Dispersed Pt Nanoparticles in Mesoporous Silica with Large Open Spaces and Their Catalytic Applications.

    PubMed

    Liu, Xianchun; Chen, Dashu; Chen, Lin; Jin, Renxi; Xing, Shuangxi; Xing, Hongzhu; Xing, Yan; Su, Zhongmin

    2016-06-27

    In this paper, a facile strategy is reported for the preparation of well-dispersed Pt nanoparticles in ordered mesoporous silica (Pt@OMS) by using a hybrid mesoporous phenolic resin-silica nanocomposite as the parent material. The phenolic resin polymer is proposed herein to be the key in preventing the aggregation of Pt nanoparticles during their formation process and making contributions both to enhance the surface area and enlarge the pore size of the support. The Pt@OMS proves to be a highly active and stable catalyst for both gas-phase oxidation of CO and liquid-phase hydrogenation of 4-nitrophenol. This work might open new avenues for the preparation of noble metal nanoparticles in mesoporous silica with unique structures for catalytic applications. PMID:27245766

  8. Manganese Oxide Nanorod-Decorated Mesoporous ZSM-5 Composite as a Precious-Metal-Free Electrode Catalyst for Oxygen Reduction.

    PubMed

    Cui, Xiangzhi; Hua, Zile; Chen, Lisong; Zhang, Xiaohua; Chen, Hangrong; Shi, Jianlin

    2016-05-10

    A precious-metal-free cathode catalyst, MnO2 nanorod-decorated mesoporous ZSM-5 zeolite nanocomposite (MnO2 / m-ZSM-5), has been successfully synthesized by a hydrothermal and electrostatic interaction approach for efficient electrochemical catalysis of the oxygen reduction reaction (ORR). The active MnOOH species, that is, Mn(4+) /Mn(3+) redox couple and Brønsted acid sites on the mesoporous ZSM-5 matrix facilitate an approximately 4 e(-) process for the catalysis of the ORR comparable to commercial 20 wt % Pt/C. Stable electrocatalytic activity with 90 % current retention after 5000 cycles, and more importantly, excellent methanol tolerance is observed. Synergetic catalytic effects between the MnO2 nanorods and the mesoporous ZSM-5 matrix are proposed to account for the high electrochemical catalytic performance. PMID:27038172

  9. Entrapping cross-linked glucose oxidase aggregates within a graphitized mesoporous carbon network for enzymatic biofuel cells.

    PubMed

    Garcia-Perez, Tsai; Hong, Sung-Gil; Kim, Jungbae; Ha, Su

    2016-08-01

    This paper reports a novel method for producing glucose oxidase-nanocomposites by entrapping cross-linked glucose oxidase (GOx) aggregates within a graphitized mesoporous carbon (GMC) network. Entrapment was achieved by utilizing the strong self-aggregation tendency of GMC in aqueous buffer solution to form carbon networks. Using confocal microscopy and TEM, GOx-GMC nanocomposites were visualized. The electrochemical properties of GOx-GMC nanocomposites were studied by means of cyclic voltammograms, chronoamperometric and potentiostatic tests. Results therefrom suggested that the GOx-GMC nanocomposites offer a high electrical conductivity with the maximum electron transfer rate constant estimated at 5.16±0.61s(-1). Furthermore, thermally treating the GOx-GMC nanocomposite and GOx aggregates at 60°C for four hours, both samples maintained 99% of their initial activity, while the free GOx were completely deactivated. These performances suggested that our nanocomposite structure offered both improved electrochemical performance and stability by combining the high electrical conductivity offered by the GMC network with the high enzyme loading and stability offered by the cross-linked GOx aggregates. The GOx-GMC nanocomposite's electrochemical activity towards glucose oxidation was also investigated by using an enzymatic biofuel cell without artificial mediators, producing a power density of up to 22.4μWcm(-2) at 0.24V. PMID:27241289

  10. Cancer therapy improvement with mesoporous silica nanoparticles combining photodynamic and photothermal therapy.

    PubMed

    Zhao, Z X; Huang, Y Z; Shi, S G; Tang, S H; Li, D H; Chen, X L

    2014-07-18

    In this work, we develop novel mesoporous silica composite nanoparticles (hm-SiO2(AlC4Pc)@Pd) for the co-delivery of photosensitizer (PS) tetra-substituted carboxyl aluminum phthalocyanine (AlC4Pc) and small Pd nanosheets as a potential dual carrier system to combine photodynamic therapy (PDT) with photothermal therapy (PTT). In the nanocomposite, PS AlC4Pc was covalently conjugated to a mesoporous silica network, and small Pd nanosheets were coated onto the surface of mesoporous silica by both coordination and electrostatic interaction. Since small Pd nanosheets and AlC4Pc display matched maximum absorptions in the 600-800 nm near-infrared (NIR) region, the fabricated hm-SiO2(AlC4Pc)@Pd nanocomposites can generate both singlet oxygen and heat upon 660 nm single continuous wavelength (CW) laser irradiation. In vitro results indicated that the cell-killing efficacy by simultaneous PDT/PTT treatment using hm-SiO2(AlC4Pc)@Pd was higher than PDT or PTT treatment alone after exposure to a 660 nm CW-NIR laser. PMID:24971525

  11. Cancer therapy improvement with mesoporous silica nanoparticles combining photodynamic and photothermal therapy

    NASA Astrophysics Data System (ADS)

    Zhao, Z. X.; Huang, Y. Z.; Shi, S. G.; Tang, S. H.; Li, D. H.; Chen, X. L.

    2014-07-01

    In this work, we develop novel mesoporous silica composite nanoparticles (hm-SiO2(AlC4Pc)@Pd) for the co-delivery of photosensitizer (PS) tetra-substituted carboxyl aluminum phthalocyanine (AlC4Pc) and small Pd nanosheets as a potential dual carrier system to combine photodynamic therapy (PDT) with photothermal therapy (PTT). In the nanocomposite, PS AlC4Pc was covalently conjugated to a mesoporous silica network, and small Pd nanosheets were coated onto the surface of mesoporous silica by both coordination and electrostatic interaction. Since small Pd nanosheets and AlC4Pc display matched maximum absorptions in the 600-800 nm near-infrared (NIR) region, the fabricated hm-SiO2(AlC4Pc)@Pd nanocomposites can generate both singlet oxygen and heat upon 660 nm single continuous wavelength (CW) laser irradiation. In vitro results indicated that the cell-killing efficacy by simultaneous PDT/PTT treatment using hm-SiO2(AlC4Pc)@Pd was higher than PDT or PTT treatment alone after exposure to a 660 nm CW-NIR laser.

  12. Magnetic γ-Fe2O3, Fe3O4, and Fe nanoparticles confined within ordered mesoporous carbons as efficient microwave absorbers.

    PubMed

    Wang, Jiacheng; Zhou, Hu; Zhuang, Jiandong; Liu, Qian

    2015-02-01

    A series of magnetic γ-Fe2O3, Fe3O4, and Fe nanoparticles have been successfully introduced into the mesochannels of ordered mesoporous carbons by the combination of the impregnation of iron salt precursors and then in situ hydrolysis, pyrolysis and reduction processes. The magnetic nanoparticles are uniformly dispersed and confined within the mesopores of mesoporous carbons. Although the as-prepared magnetic mesoporous carbon composites have high contents of magnetic components, they still possess very high specific surface areas and pore volumes. The magnetic hysteresis loops measurements indicate that the magnetic constituents are poorly-crystalline nanoparticles and their saturation magnetization is evidently smaller than bulky magnetic materials. The confinement of magnetic nanoparticles within the mesopores of mesoporous carbons results in the decrease of the complex permittivity and the increase of the complex permeability of the magnetic nanocomposites. The maximum reflection loss (RL) values of -32 dB at 11.3 GHz and a broad absorption band (over 2 GHz) with RL values <-10 dB are obtained for 10-Fe3O4-CMK-3 and 10-γ-Fe2O3-CMK-3 composites in a frequency range of 8.2-12.4 GHz (X-band), showing their great potentials in microwave absorption. This research opens a new method and idea for developing novel magnetic mesoporous carbon composites as high-performance microwave absorbing materials. PMID:25562071

  13. Improvements of reinforced silica aerogel nanocomposites thermal properties for architecture applications.

    PubMed

    Saboktakin, Amin; Saboktakin, Mohammad Reza

    2015-01-01

    An 1,4-cis polybutadiene rubber/carboxymethyl starch (CMS)-based silica aerogel nanocomposites as a insulation material was developed that will provide superior thermal insulation properties, flexibility, toughness, durability of the parent polymer, yet with the low density and superior insulation properties associated with the aerogels. In this study, reinforced 1,4-cis polybutadiene-CMS-silica aerogel nanocomposites were prepared from a silica aerogel with a surface area 710 m(2) g(-1), a pore size of 25.3 nm and a pore volume of 4.7 cm(3) g(-1). The tensile properties and dynamic mechanical properties of 1,4-cis polybutadiene/CMS nanocomposites were systematically enhanced at low silica loading. Similar improvements in tensile modulus and strength have been observed for 1,4-cis polybutadiene/CMS mesoporous silica aerogel nanocomposites. PMID:25172161

  14. Nanoionics and Nanocatalysts: Conformal Mesoporous Surface Scaffold for Cathode of Solid Oxide Fuel Cells

    PubMed Central

    Chen, Yun; Gerdes, Kirk; Song, Xueyan

    2016-01-01

    Nanoionics has become increasingly important in devices and systems related to energy conversion and storage. Nevertheless, nanoionics and nanostructured electrodes development has been challenging for solid oxide fuel cells (SOFCs) owing to many reasons including poor stability of the nanocrystals during fabrication of SOFCs at elevated temperatures. In this study, a conformal mesoporous ZrO2 nanoionic network was formed on the surface of La1−xSrxMnO3/yttria-stabilized zirconia (LSM/YSZ) cathode backbone using Atomic Layer Deposition (ALD) and thermal treatment. The surface layer nanoionic network possesses open mesopores for gas penetration, and features a high density of grain boundaries for enhanced ion-transport. The mesoporous nanoionic network is remarkably stable and retains the same morphology after electrochemical operation at high temperatures of 650–800 °C for 400 hours. The stable mesoporous ZrO2 nanoionic network is further utilized to anchor catalytic Pt nanocrystals and create a nanocomposite that is stable at elevated temperatures. The power density of the ALD modified and inherently functional commercial cells exhibited enhancement by a factor of 1.5–1.7 operated at 0.8 V at 750 °C. PMID:27605121

  15. Nanoionics and Nanocatalysts: Conformal Mesoporous Surface Scaffold for Cathode of Solid Oxide Fuel Cells.

    PubMed

    Chen, Yun; Gerdes, Kirk; Song, Xueyan

    2016-01-01

    Nanoionics has become increasingly important in devices and systems related to energy conversion and storage. Nevertheless, nanoionics and nanostructured electrodes development has been challenging for solid oxide fuel cells (SOFCs) owing to many reasons including poor stability of the nanocrystals during fabrication of SOFCs at elevated temperatures. In this study, a conformal mesoporous ZrO2 nanoionic network was formed on the surface of La1-xSrxMnO3/yttria-stabilized zirconia (LSM/YSZ) cathode backbone using Atomic Layer Deposition (ALD) and thermal treatment. The surface layer nanoionic network possesses open mesopores for gas penetration, and features a high density of grain boundaries for enhanced ion-transport. The mesoporous nanoionic network is remarkably stable and retains the same morphology after electrochemical operation at high temperatures of 650-800 °C for 400 hours. The stable mesoporous ZrO2 nanoionic network is further utilized to anchor catalytic Pt nanocrystals and create a nanocomposite that is stable at elevated temperatures. The power density of the ALD modified and inherently functional commercial cells exhibited enhancement by a factor of 1.5-1.7 operated at 0.8 V at 750 °C. PMID:27605121

  16. Mesoporous Silicate Materials in Sensing

    PubMed Central

    Melde, Brian J.; Johnson, Brandy J.; Charles, Paul T.

    2008-01-01

    Mesoporous silicas, especially those exhibiting ordered pore systems and uniform pore diameters, have shown great potential for sensing applications in recent years. Morphological control grants them versatility in the method of deployment whether as bulk powders, monoliths, thin films, or embedded in coatings. High surface areas and pore sizes greater than 2 nm make them effective as adsorbent coatings for humidity sensors. The pore networks also provide the potential for immobilization of enzymes within the materials. Functionalization of materials by silane grafting or through co-condensation of silicate precursors can be used to provide mesoporous materials with a variety of fluorescent probes as well as surface properties that aid in selective detection of specific analytes. This review will illustrate how mesoporous silicas have been applied to sensing changes in relative humidity, changes in pH, metal cations, toxic industrial compounds, volatile organic compounds, small molecules and ions, nitroenergetic compounds, and biologically relevant molecules.

  17. Aligned mesoporous architectures and devices.

    SciTech Connect

    Brinker, C. Jeffrey; Lu, Yunfeng

    2011-03-01

    This is the final report for the Presidential Early Career Award for Science and Engineering - PECASE (LDRD projects 93369 and 118841) awarded to Professor Yunfeng Lu (Tulane University and University of California-Los Angeles). During the last decade, mesoporous materials with tunable periodic pores have been synthesized using surfactant liquid crystalline as templates, opening a new avenue for a wide spectrum of applications. However, the applications are somewhat limited by the unfavorabe pore orientation of these materials. Although substantial effort has been devoted to align the pore channels, fabrication of mesoporous materials with perpendicular pore channels remains challenging. This project focused on fabrication of mesoporous materials with perpendicularly aligned pore channels. We demonstrated structures for use in water purification, separation, sensors, templated synthesis, microelectronics, optics, controlled release, and highly selective catalysts.

  18. Single crystalline mesoporous silicon nanowires

    SciTech Connect

    Hochbaum, Allon; Dargas, Daniel; Hwang, Yun Jeong; Yang, Peidong

    2009-08-18

    Herein we demonstrate a novel electroless etching synthesis of monolithic, single-crystalline, mesoporous silicon nanowire arrays with a high surface area and luminescent properties consistent with conventional porous silicon materials. The photoluminescence of these nanowires suggest they are composed of crystalline silicon with small enough dimensions such that these arrays may be useful as photocatalytic substrates or active components of nanoscale optoelectronic devices. A better understanding of this electroless route to mesoporous silicon could lead to facile and general syntheses of different narrow bandgap semiconductor nanostructures for various applications.

  19. Magnetic mesoporous material for the sequestration of algae

    SciTech Connect

    Trewyn, Brian G.; Kandel, Kapil; Slowing, Igor Ivan; Lee, Show-Ling

    2014-09-09

    The present invention provides a magnetic mesoporous nanoparticle that includes a mesoporous silicate nanoparticle and iron oxide. The present invention also provides a method of using magnetic mesoporous nanoparticles to sequester microorganisms from a media.

  20. Bimodal mesoporous silica with bottleneck pores.

    PubMed

    Reber, M J; Brühwiler, D

    2015-11-01

    Bimodal mesoporous silica consisting of two sets of well-defined mesopores is synthesized by a partial pseudomorphic transformation of an ordered mesoporous starting material (SBA-15 type). The introduction of a second set of smaller mesopores (MCM-41 type) establishes a pore system with bottlenecks that restricts the access to the core of the bimodal mesoporous silica particles. The particle size and shape of the starting material are retained, but micropores present in the starting material disappear during the transformation, leading to a true bimodal mesoporous product. A varying degree of transformation allows the adjustment of the pore volume contribution of the two mesopore domains. Information on the accessibility of the mesopores is obtained by the adsorption of fluorescence-labeled poly(amidoamine) dendrimers and imaging by confocal laser scanning microscopy. This information is correlated with nitrogen sorption data to provide insights regarding the spatial distribution of the two mesopore domains. The bimodal mesoporous materials are excellent model systems for the investigation of cavitation effects in nitrogen desorption isotherms. PMID:26399172

  1. Analytical and Theranostic Applications of Gold Nanoparticles and Multifunctional Nanocomposites

    PubMed Central

    Khlebtsov, Nikolai; Bogatyrev, Vladimir; Dykman, Lev; Khlebtsov, Boris; Staroverov, Sergey; Shirokov, Alexander; Matora, Larisa; Khanadeev, Vitaly; Pylaev, Timofey; Tsyganova, Natalia; Terentyuk, Georgy

    2013-01-01

    Gold nanoparticles (GNPs) and GNP-based multifunctional nanocomposites are the subject of intensive studies and biomedical applications. This minireview summarizes our recent efforts in analytical and theranostic applications of engineered GNPs and nanocomposites by using plasmonic properties of GNPs and various optical techniques. Specifically, we consider analytical biosensing; visualization and bioimaging of bacterial, mammalian, and plant cells; photodynamic treatment of pathogenic bacteria; and photothermal therapy of xenografted tumors. In addition to recently published reports, we discuss new data on dot immunoassay diagnostics of mycobacteria, multiplexed immunoelectron microscopy analysis of Azospirillum brasilense, materno-embryonic transfer of GNPs in pregnant rats, and combined photodynamic and photothermal treatment of rat xenografted tumors with gold nanorods covered by a mesoporous silica shell doped with hematoporphyrin. PMID:23471188

  2. Mesoporous Silicon-Based Anodes

    NASA Technical Reports Server (NTRS)

    Peramunage, Dharmasena

    2015-01-01

    For high-capacity, high-performance lithium-ion batteries. A new high-capacity anode composite based on mesoporous silicon is being developed. With a structure that resembles a pseudo one-dimensional phase, the active anode material will accommodate significant volume changes expected upon alloying and dealloying with lithium (Li).

  3. THE BIOCOMPATIBILITY OF MESOPOROUS SILICATES

    PubMed Central

    Hudson, Sarah; Padera, Robert F.; Langer, Robert; Kohane, Daniel S.

    2008-01-01

    Micro- and nano- mesoporous silicate particles are considered potential drug delivery systems because of their ordered pore structures, large surface areas and the ease with which they can be chemically modified. However, few cytotoxicity or biocompatibility studies have been reported, especially when silicates are administered in the quantities necessary to deliver low-potency drugs. The biocompatibility of mesoporous silicates of particle sizes ~ 150 nm, ~ 800 nm and ~ 4 µm and pore sizes of 3 nm, 7 nm and 16 nm respectively are examined here. In vitro, mesoporous silicates showed a significant degree of toxicity at high concentrations with mesothelial cells. Following subcutaneous injection of silicates in rats, the amount of residual material decreased progressively over three months, with good biocompatibility on histology at all time points. In contrast, intra peritoneal and intra venous injections in mice resulted in death or euthanasia. No toxicity was seen with subcutaneous injection of the same particles in mice. Microscopic analysis of the lung tissue of the mice indicates that death may be due to thrombosis. Although local tissue reaction to mesoporous silicates was benign, they caused severe systemic toxicity. This toxicity could be mitigated by modification of the materials. PMID:18675454

  4. Synthesis and characterization of mesoporous materials

    NASA Astrophysics Data System (ADS)

    Cheng, Wei

    Mesoporous materials are highly porous solids with pore sizes in the range of 20 to 500 A and a narrow pore size distribution. Creating a mesoporous morphology in transition metal oxides is expected to increase the kinetics of electrochemical photoelectrochemical processes due to the improved accessibility of electrolyte to electrode. The objective of the dissertation research is to prepare functional mesoporous materials based on transition metal oxides and to determine the effects of the mesoporous structure on the resulting charge transfer, electrochromism, and optical properties. In this dissertation, mesoporous tungsten oxide and niobium oxide were synthesized by incorporating tri-block copolymer surfactant templates into the sol-gel synthesis procedure. Both mesoporous materials have surface areas in the range of 130 m2/g with a narrow pore size distribution centered at ˜45A. Their electrochromic properties were characterized and found to be strongly influenced by the mesoporous morphology. Both mesoporous systems exhibit better electrochemical and optical reversibilities than the analogous sol-gel materials (without using surfactant) and the kinetics of bleaching is substantially faster. Coloration efficiencies for the mesoporous tungsten oxide and niobium oxide films are in the range of 16--37 cm 2/C and 12--16 cm2/C, respectively. Dye sensitized solar cells (DSSC) were fabricated using mesoporous niobium oxide as electrodes. Due to the higher surface area, the mesoporous electrodes have greater dye adsorption and electrolyte penetration compared to sol-gel electrodes, which leads to better electron injection, faster dye regeneration and thus, better cell performance. The mesoporous DSSC exhibits photocurrents of 2.9 mA and fill factors of 0.61. Open circuit voltages of the mesoporous DSSC are in the range of 0.6--0.83V.

  5. Activators generated by electron transfer for atom transfer radical polymerization of styrene in the presence of mesoporous silica nanoparticles

    SciTech Connect

    Khezri, Khezrollah; Roghani-Mamaqani, Hossein

    2014-11-15

    Graphical abstract: Effect of mesoporous silica nanoparticles (MCM-41) on the activator generated by electron transfer for atom transfer radical polymerization (AGET ATRP) is investigated. Decrement of conversion and number average molecular weight and also increment of polydispersity index (PDI) values are three main results of addition of MCM-41 nanoparticles. Incorporation of MCM-41 nanoparticles in the polystyrene matrix can clearly increase thermal stability and decrease glass transition temperature of the nanocomposites. - Highlights: • Spherical morphology, hexagonal structure, and high surface area with regular pore diameters of the synthesized MCM-41 nanoparticles are examined. • AGET ATRP of styrene in the presence of MCM-41 nanoparticles is performed. • Effect of MCM-41 nanoparticles addition on the polymerization rate, conversion and molecular weights of the products are discussed. • Improvement in thermal stability of the nanocomposites and decreasing T{sub g} values was also observed by incorporation of MCM-41 nanoparticles. - Abstract: Activator generated by electron transfer for atom transfer radical polymerization was employed to synthesize well-defined mesoporous silica nanoparticles/polystyrene composites. Inherent features of spherical mesoporous silica nanoparticles were evaluated by nitrogen adsorption/desorption isotherm, X-ray diffraction and scanning electron microscopy analysis techniques. Conversion and molecular weight evaluations were carried out using gas and size exclusion chromatography respectively. By the addition of only 3 wt% mesoporous silica nanoparticles, conversion decreases from 81 to 58%. Similarly, number average molecular weight decreases from 17,116 to 12,798 g mol{sup −1}. However, polydispersity index (PDI) values increases from 1.24 to 1.58. A peak around 4.1–4.2 ppm at proton nuclear magnetic resonance spectroscopy results clearly confirms the living nature of the polymerization. Thermogravimetric

  6. A co-sol-emulsion-gel synthesis of tunable and uniform hollow carbon nanospheres with interconnected mesoporous shells

    NASA Astrophysics Data System (ADS)

    Hou, Jianhua; Cao, Tai; Idrees, Faryal; Cao, Chuanbao

    2015-12-01

    Monodispersed mesoporous hollow spheres of polymer-silica and carbon-silica nanocomposites with an ``interpenetration twin'' nanostructure have been successfully synthesized by a co-sol-emulsion-gel method. The obtained mesoporous hollow carbon spheres (MHCSs) exhibited an open interconnected mesoporous shell that is endowed with high specific surface area (SBET, 2106-2225 m2 g-1) and large pore volume (1.95-2.53 cm3 g-1). Interestingly, the diameter of the uniform MHCSs could be precisely tuned on demand, as an effective electrode material in supercapacitors, MHCSs with a diameter of 90 nm deliver the shortest time constant (τ0 = 0.75 s), which is highly beneficial for rate capacitance (180 F g-1 at 100 A g-1, a full charge-discharge within 0.9 s) and cyclic retainability (3% loss after 20 000 cycles). The newly developed synthesis route leads to unique interconnected mesoporous hollow carbonaceous spheres with open-framework structures, providing a new material platform in energy storage.Monodispersed mesoporous hollow spheres of polymer-silica and carbon-silica nanocomposites with an ``interpenetration twin'' nanostructure have been successfully synthesized by a co-sol-emulsion-gel method. The obtained mesoporous hollow carbon spheres (MHCSs) exhibited an open interconnected mesoporous shell that is endowed with high specific surface area (SBET, 2106-2225 m2 g-1) and large pore volume (1.95-2.53 cm3 g-1). Interestingly, the diameter of the uniform MHCSs could be precisely tuned on demand, as an effective electrode material in supercapacitors, MHCSs with a diameter of 90 nm deliver the shortest time constant (τ0 = 0.75 s), which is highly beneficial for rate capacitance (180 F g-1 at 100 A g-1, a full charge-discharge within 0.9 s) and cyclic retainability (3% loss after 20 000 cycles). The newly developed synthesis route leads to unique interconnected mesoporous hollow carbonaceous spheres with open-framework structures, providing a new material platform in

  7. Nanostructure-loaded mesoporous silica for controlled release of coumarin derivatives: a novel testing of the hyperthermia effect.

    PubMed

    Al-Kady, Ahmed S; Gaber, M; Hussein, Mohamed M; Ebeid, El-Zeiny M

    2011-01-01

    The synthesis of three types of mesoporous materials is reported: pure mesoporous silica (MCM-41), a nanocomposite of mesoporous silica with hydroxyapatite (MCM-41-HA) and mesoporous silica/gold nanorods nanocomposite (MCM-41-GNRs). The mesoporous materials were characterized by X-ray diffraction, N(2) adsorption isotherms, FTIR spectroscopy, transmission electron microscopy, and scanning electron microscopy. The samples were loaded with coumarin thiourea derivatives (I-IV) having functional groups of varying sizes and the in vitro release assays were monitored, and the release behavior was investigated as a function of soaking time in simulated body fluid. Two release stages were obtained in MCM-41, MCM-41-HA and MCM-41-GNRs loaded samples with the early release stages accounting for about 30% of loaded derivatives. These early release stages are characterized by Higuchi rate constant values nearly twice the values associated with the second release stages. The influence of substituent size on the release rate constants was explained in terms of sorption sites and hydrogen bonding with silanol groups on silicates. The release of coumarin derivatives loaded on MCM-41, MCM-41-HA and MCM-41-GNRs occurs over remarkably long time of the order of about 260 h with faster release rates in loaded MCM-41 and MCM-41-GNRs samples compared with MCM-41-HA ones. The role of hyperthermia effect in enhancing release rates was investigated by subjecting loaded MCM-41-GNRs to near infrared (NIR) radiation at 800 nm. This would be of significance in targeted drug release using hyperthermia effect. Unlike hydroxyl apatite, loading MCM-41 with gold nanorods does not affect the release kinetics. Only when these samples are irradiated with NIR photons, does the release occur with enhanced rates. This property could be valuable in selected targeting of drugs. PMID:20974253

  8. SnCo–CMK nanocomposite with improved electrochemical performance for lithium-ion batteries

    SciTech Connect

    Zeng, Lingxing; Deng, Cuilin; Zheng, Cheng; Qiu, Heyuan; Qian, Qingrong; Chen, Qinghua; Wei, Mingdeng

    2015-11-15

    Highlights: • The SnCo–CMK nanocomposite was synthesized using mesoporous carbon as nano-reactor. • Ultrafine SnCo nanoparticles distribute both inside and outside of mesopore channels. • The SnCo–CMK nanocomposite is an alternative anode material for Li-ion intercalation. • A high reversible capacity of 562 mAh g{sup −1} is maintained after 60 cycles at 100 mA g{sup −1}. - Abstract: In the present work, SnCo–CMK nanocomposite was successfully synthesized for the first time via a simple nanocasting route by using mesoporous carbon as nano-reactor. The nanocomposite was then characterized by means of X-ray diffraction (XRD), thermogravimetric analysis (TG), N{sub 2} adsorption–desorption, scanning and transmission electron microscopy (SEM/TEM) respectively. Furthermore, the SnCo–CMK nanocomposite exhibited large reversible capacities, excellent cycling stability and enhanced rate capability when employed as an anode material for lithium-ion batteries. A large reversible capacity of 562 mA h g{sup −1} was obtained after 60 cycles at a current density of 0.1 A g{sup −1} which is attributed to the structure of ‘meso-nano’ SnCo–CMK composite. This unique structure ensures the intimate contact between CMK and SnCo nanoparticles, buffers the large volume expansion and prevents the aggregation of the SnCo nanoparticles during cycling, leading to the excellent cycling stability and enhanced rate capability.

  9. Mesoporous Silica: A Suitable Adsorbent for Amines

    PubMed Central

    2009-01-01

    Mesoporous silica with KIT-6 structure was investigated as a preconcentrating material in chromatographic systems for ammonia and trimethylamine. Its adsorption capacity was compared to that of existing commercial materials, showing its increased adsorption power. In addition, KIT-6 mesoporous silica efficiently adsorbs both gases, while none of the employed commercial adsorbents did. This means that KIT-6 Mesoporous silica may be a good choice for integrated chromatography/gas sensing micro-devices. PMID:20628459

  10. Synthesis of non-siliceous mesoporous oxides.

    PubMed

    Gu, Dong; Schüth, Ferdi

    2014-01-01

    Mesoporous non-siliceous oxides have attracted great interest due to their unique properties and potential applications. Since the discovery of mesoporous silicates in 1990s, organic-inorganic assembly processes by using surfactants or block copolymers as soft templates have been considered as a feasible path for creating mesopores in metal oxides. However, the harsh sol-gel conditions and low thermal stabilities have limited the expansion of this method to various metal oxide species. Nanocasting, using ordered mesoporous silica or carbon as a hard template, has provided possibilities for preparing novel mesoporous materials with new structures, compositions and high thermal stabilities. This review concerns the synthesis, composition, and parameter control of mesoporous non-siliceous oxides. Four synthesis routes, i.e. soft-templating (surfactants or block copolymers as templates), hard-templating (mesoporous silicas or carbons as sacrificial templates), colloidal crystal templating (3-D ordered colloidal particles as a template), and super lattice routes, are summarized in this review. Mesoporous metal oxides with different compositions have different properties. Non-siliceous mesoporous oxides are comprehensively described, including a discussion of constituting elements, synthesis, and structures. General aspects concerning pore size control, atomic scale crystallinity, and phase control are also reviewed. PMID:23942521

  11. Cellular membrane trafficking of mesoporous silica nanoparticles

    SciTech Connect

    Fang, I-Ju

    2012-01-01

    This dissertation mainly focuses on the investigation of the cellular membrane trafficking of mesoporous silica nanoparticles. We are interested in the study of endocytosis and exocytosis behaviors of mesoporous silica nanoparticles with desired surface functionality. The relationship between mesoporous silica nanoparticles and membrane trafficking of cells, either cancerous cells or normal cells was examined. Since mesoporous silica nanoparticles were applied in many drug delivery cases, the endocytotic efficiency of mesoporous silica nanoparticles needs to be investigated in more details in order to design the cellular drug delivery system in the controlled way. It is well known that cells can engulf some molecules outside of the cells through a receptor-ligand associated endocytosis. We are interested to determine if those biomolecules binding to cell surface receptors can be utilized on mesoporous silica nanoparticle materials to improve the uptake efficiency or govern the mechanism of endocytosis of mesoporous silica nanoparticles. Arginine-glycine-aspartate (RGD) is a small peptide recognized by cell integrin receptors and it was reported that avidin internalization was highly promoted by tumor lectin. Both RGD and avidin were linked to the surface of mesoporous silica nanoparticle materials to investigate the effect of receptor-associated biomolecule on cellular endocytosis efficiency. The effect of ligand types, ligand conformation and ligand density were discussed in Chapter 2 and 3. Furthermore, the exocytosis of mesoporous silica nanoparticles is very attractive for biological applications. The cellular protein sequestration study of mesoporous silica nanoparticles was examined for further information of the intracellular pathway of endocytosed mesoporous silica nanoparticle materials. The surface functionality of mesoporous silica nanoparticle materials demonstrated selectivity among the materials and cancer and normal cell lines. We aimed to determine

  12. Mesoporous BaTiO₃@SBA-15 derived via solid state reaction and its excellent adsorption efficiency for the removal of hexavalent chromium from water.

    PubMed

    Kumari, Vandana; Sasidharan, Manickam; Bhaumik, Asim

    2015-01-28

    We report the synthesis of a barium-titanate/mesoporous silica nanocomposite material BaTiO3@SBA-15 via aerosol assisted solid state reaction using SBA-15 as a hard template. Hexavalent chromium is one of the most harmful contaminants of industrial waste-water. We have used BaTiO3@SBA-15 nanocomposite as an adsorbent for the removal of chromium(vi)-contaminated water and it showed an adsorption capacity of 98.2 wt% within only 40 min contact time in a batch reactor. This mesoporous composite has retained this excellent adsorption efficiency of hexavalent chromium for several repetitive cycles, suggesting its future potential for the remediation of water contaminated with Cr(vi). PMID:25490743

  13. 2D and 3D characterization of a surfactant-synthesized TiO2-SiO2 mesoporous photocatalyst obtained at ambient temperature.

    PubMed

    Pinho, Luís; Hernández-Garrido, Juan C; Calvino, Juan J; Mosquera, Maria J

    2013-02-28

    A mesoporous TiO(2)-SiO(2) nanocomposite photocatalyst has been prepared from TiO(2) nanoparticles and ethoxysilane oligomers in the presence of a non-ionic surfactant (n-octylamine). The 2D and 3D structure properties of the resulting nanomaterial are described. The use of 3D techniques, particularly HAADF-STEM electron tomography, together with 3D reconstructions and atomic force microscopy, provides insight into the fine structure of these materials. We find that n-octylamine creates a mesoporous silica structure in which titania nanoparticles are embedded, and that some of the titania is retained on the outer surface of the material. Rapid photodegradation of methylene blue dye is facilitated, due to the synergistic effect of: (1) its adsorption into the composite mesoporous structure, and (2) its photodegradation by the superficial TiO(2). PMID:23338827

  14. Magnetic Mesoporous Photonic Cellulose Films.

    PubMed

    Giese, Michael; Blusch, Lina K; Schlesinger, Maik; Meseck, Georg R; Hamad, Wadood Y; Arjmand, Mohammad; Sundararaj, Uttandaraman; MacLachlan, Mark J

    2016-09-13

    Novel hybrid materials of cellulose and magnetic nanoparticles (NPs) were synthesized and characterized. The materials combine the chiral nematic structural features of mesoporous photonic cellulose (MPC) with the magnetic properties of cobalt ferrite (CoFe2O4). The photonic, magnetic, and dielectric properties of the hybrid materials were investigated during the dynamic swelling and deswelling of the MPC films. It was observed that the dielectric properties of the generated MPC films increased tremendously following swelling in water, endorsing efficient swelling ability of the generated mesoporous films. The high magnetic permeability of the developed MPC films in conjunction with their superior dielectric properties, predominantly in the swollen state, makes them interesting for electromagnetic interference shielding applications. PMID:27588561

  15. Hierarchically Structured Sulfur/Carbon Nanocomposite Material for High Energy Lithium Battery

    SciTech Connect

    Liang, Chengdu; Dudney, Nancy J; Howe, Jane Y

    2009-01-01

    We report herein a hierarchically structured sulfur-carbon (S/C) nanocomposite material as the high surface-area cathode for rechargeable lithium batteries. A porous carbon with a uniform distribution of mesopores of 7.3 nm has been synthesized through a soft-template synthesis method. The potassium hydroxide activation of this mesoporous carbon results in a bimodal porous carbon with added microporosity of less than 2 nm to the existing mesopores without deterioration of the integrity of the original mesoporous carbon. Elemental sulfur has been loaded to the micropores through a solution infiltration method. The resulted S/C composites with various loading level of sulfur have a high surface areas and large internal porosities. These materials have been tested as novel cathodes for Li/S batteries. The results show that the cyclability and the utilization of sulfur in the Li/S batteries have been significantly improved. The large internal porosity and surface area of the micro-mesoporous carbon is essential for retaining sulfur in the cathode and therefore maximizing the capacity and lifespan of the cathode.

  16. Investigating the mesostructure of ordered porous silica nanocomposites by transmission electron microscopy techniques

    SciTech Connect

    Bullita, S.; Casula, M. F.; Piludu, M.; Falqui, A.; Carta, D.; Corrias, A.

    2014-10-21

    Nanocomposites made out of FeCo alloy nanocrystals supported onto pre-formed mesoporous ordered silica which features a cubic arrangement of pores (SBA-16) were investigated. Information on the effect of the nanocrystals on the mesostructure (i.e. pore arrangement symmetry, pore size, and shape) were deduced by a multitechnique approach including N2 physisorption, low angle X-ray diffraction, and Transmission electron microscopy. It is shown that advanced transmission electron microscopy techniques are required, however, to gain direct evidence on key compositional and textural features of the nanocomposites. In particular, electron tomography and microtomy techniques make clear that the FeCo nanocrystals are located within the pores of the SBA-16 silica, and that the ordered mesostructure of the nanocomposite is retained throughout the observed specimen.

  17. Novel concept for the preparation of gas selective nanocomposite membranes

    NASA Astrophysics Data System (ADS)

    Drobek, M.; Ayral, A.; Motuzas, J.; Charmette, C.; Loubat, C.; Louradour, E.; Dhaler, D.; Julbe, A.

    2015-07-01

    In this work we report on a novel concept for the preparation of gas selective composite membranes by a simple and robust synthesis protocol involving a controlled in-situpolycondensation of functional alkoxysilanes within the pores of a mesoporous ceramic matrix. This innovative approach targets the manufacture of thin nanocomposite membranes, allowing good compromise between permeability, selectivity and thermomechanical strength. Compared to simple infiltration, the synthesis protocol allows a controlled formation of gas separation membranes from size-adjusted functional alkoxysilanes by a chemical reaction within the mesopores of a ceramic support, without any formation of a thick and continuous layer on the support top-surface. Membrane permeability can thus be effectively controlled by the thickness and pore size of the mesoporous layer, and by the oligomers chain length. The as-prepared composite membranes are expected to possess a good mechanical and thermomechanical resistance and exhibit a thermally activated transport of He and H2 up to 150 °C, resulting in enhanced separation factors for specific gas mixtures e.g. FH2/CO ˜ 10; FH2/CO2 ˜ 3; FH2/CH4 ˜ 62.

  18. Mesoporous carbonates and method of making

    DOEpatents

    Fryxell, Glen; Liu, Jun; Zemanian, Thomas S.

    2004-06-15

    Mesoporous metal carbonate structures are formed by providing a solution containing a non-ionic surfactant and a calcium acetate salt, adding sufficient base to react with the acidic byproducts to be formed by the addition of carbon dioxide, and adding carbon dioxide, thereby forming a mesoporous metal carbonate structure containing the metal from said metal salt.

  19. Synthesis of hollow and mesoporous polycaprolactone nanocapsules,

    NASA Astrophysics Data System (ADS)

    Paik, Pradip; Zhang, Yong

    2011-05-01

    New polycaprolactone (PCL) nanocapsules with a hollow core and mesoporous shell have been synthesized. The PCL nanocapsules have an average size of about 100nm and a mesopores shell of about 20nm. The size of the mesopores on the shell is about 4nm. Fluorescent dye Rhodamin 6G was loaded into the nanocapsules to demonstrate the mesoporous structure of the capsules and their ability to load small molecules. The nanocapsules with such a structure can be used in many areas for various applications such as drug and gene delivery.New polycaprolactone (PCL) nanocapsules with a hollow core and mesoporous shell have been synthesized. The PCL nanocapsules have an average size of about 100nm and a mesopores shell of about 20nm. The size of the mesopores on the shell is about 4nm. Fluorescent dye Rhodamin 6G was loaded into the nanocapsules to demonstrate the mesoporous structure of the capsules and their ability to load small molecules. The nanocapsules with such a structure can be used in many areas for various applications such as drug and gene delivery. Dr. Pradip Paik is currently an assistant professor at the University of Hyderabad (Central University), India.

  20. Mesoporous Nano-Silica Serves as the Degradation Inhibitor in Polymer Dielectrics

    NASA Astrophysics Data System (ADS)

    Yang, Yang; Hu, Jun; He, Jinliang

    2016-06-01

    A new generation of nano-additives for robust high performance nanodielectrics is proposed. It is demonstrated for the first time that mesoporous material could act as “degradation inhibitor” for polymer dielectrics to sequestrate the electrical degradation products then restrain the electrical aging process especially under high temperature conditions, which is superior to the existing additives of nanodielectrics except further increasing the dielectric strength. Polyethylenimine (PEI) loaded nano-scaled mesoporous silica MCM-41 (nano-MS) is doped into the dielectric matrix to prepare the PP/MCM-41-PEI nanocomposites. PEI provides the amines to capture the electrical degradation products while the MCM-41 brackets afford large adsorption surface, bring down the activating temperature of the absorbent then enhance the absorptive capacity. The electrical aging tests confirm the contribution of the mesoporous structure to electrical aging resistance and FT-IR analysis of the electrical degraded regions demonstrates the chemical absorption especially under high temperature conditions. Take the experimental data as examples, extending the aging durability and dielectric strength of polymer dielectrics by 5 times and 16%, respectively, can have substantial commercial significance in energy storage, power electronics and power transmission areas.

  1. Direct Assembly of Mesoporous Silica Functionalized with Polypeptides for Efficient Dye Adsorption.

    PubMed

    Lu, Yi-Syuan; Bastakoti, Bishnu Prasad; Pramanik, Malay; Malgras, Victor; Yamauchi, Yusuke; Kuo, Shiao-Wei

    2016-01-18

    Herein, we introduce a new polypeptide-functionalized mesoporous silica template fabricated from a biodegradable poly(ethylene oxide-b-ɛ-caprolactone) (PEO-b-PCL) diblock copolymer and a poly(tyrosine) (PTyr) biopolymer. The crystallization behavior of the PEO-b-PCL diblock copolymer changes after blending, but the secondary structure of PTry remains stable. After selective solvent extraction in THF, the PEO-b-PCL is removed, but PTyr remains within the silica matrix due to its different solubility. Fourier-transform IR spectroscopic analysis (FTIR), thermal gravitometry analysis (TGA), small-angle X-ray scattering (SAXS), and X-ray diffraction (XRD) studies confirm the retention of PTyr to form a polypeptide-functionalized mesoporous material. The adsorption of methylene blue hydrate (MB) from aqueous solution into the polypeptide-functionalized mesoporous silica is investigated, thus revealing that the nanocomposite exhibits a high adsorption capacity relative to pure silica due to hydrogen-bonding interactions between the hydroxy phenolic group of PTyr and the N-containing aromatic ring from MB. PMID:26626026

  2. Mesoporous Nano-Silica Serves as the Degradation Inhibitor in Polymer Dielectrics.

    PubMed

    Yang, Yang; Hu, Jun; He, Jinliang

    2016-01-01

    A new generation of nano-additives for robust high performance nanodielectrics is proposed. It is demonstrated for the first time that mesoporous material could act as "degradation inhibitor" for polymer dielectrics to sequestrate the electrical degradation products then restrain the electrical aging process especially under high temperature conditions, which is superior to the existing additives of nanodielectrics except further increasing the dielectric strength. Polyethylenimine (PEI) loaded nano-scaled mesoporous silica MCM-41 (nano-MS) is doped into the dielectric matrix to prepare the PP/MCM-41-PEI nanocomposites. PEI provides the amines to capture the electrical degradation products while the MCM-41 brackets afford large adsorption surface, bring down the activating temperature of the absorbent then enhance the absorptive capacity. The electrical aging tests confirm the contribution of the mesoporous structure to electrical aging resistance and FT-IR analysis of the electrical degraded regions demonstrates the chemical absorption especially under high temperature conditions. Take the experimental data as examples, extending the aging durability and dielectric strength of polymer dielectrics by 5 times and 16%, respectively, can have substantial commercial significance in energy storage, power electronics and power transmission areas. PMID:27338622

  3. Mesoporous Nano-Silica Serves as the Degradation Inhibitor in Polymer Dielectrics

    PubMed Central

    Yang, Yang; Hu, Jun; He, Jinliang

    2016-01-01

    A new generation of nano-additives for robust high performance nanodielectrics is proposed. It is demonstrated for the first time that mesoporous material could act as “degradation inhibitor” for polymer dielectrics to sequestrate the electrical degradation products then restrain the electrical aging process especially under high temperature conditions, which is superior to the existing additives of nanodielectrics except further increasing the dielectric strength. Polyethylenimine (PEI) loaded nano-scaled mesoporous silica MCM-41 (nano-MS) is doped into the dielectric matrix to prepare the PP/MCM-41-PEI nanocomposites. PEI provides the amines to capture the electrical degradation products while the MCM-41 brackets afford large adsorption surface, bring down the activating temperature of the absorbent then enhance the absorptive capacity. The electrical aging tests confirm the contribution of the mesoporous structure to electrical aging resistance and FT-IR analysis of the electrical degraded regions demonstrates the chemical absorption especially under high temperature conditions. Take the experimental data as examples, extending the aging durability and dielectric strength of polymer dielectrics by 5 times and 16%, respectively, can have substantial commercial significance in energy storage, power electronics and power transmission areas. PMID:27338622

  4. Non-destructively shattered mesoporous silica for protein drug delivery

    SciTech Connect

    Lei, Chenghong; Chen, Baowei; Li, Xiaolin; Qi, Wen N.; Liu, Jun

    2013-07-15

    Mesoporous silicas have been extensively used for entrapping small chemical molecules and biomacromolecules. We hypothesize that the loading density of biomacromlecules such as proteins in mesoporous silicas could be limited due to mesopore disorderness and depth because of some pore volume inaccessible. We innovatively shattered mesoporous silicas resulting in reduced particle sizes and improved intramesoporous structures in aqueous solution by a powerful sonication, where the mesoporous structures were still well maintained. The sonication-shattered mesoporous silicas can allow protein loading densities to be increased by more than 170%, demonstrating that significantly more mesoporous room of the silicas could become accessible for biomacromolecule loading after the sonication-shattering.

  5. Mesoporous Carbon-based Materials for Alternative Energy Applications

    NASA Astrophysics Data System (ADS)

    Cross, Kimberly Michelle

    Increasing concerns for the escalating issues activated by the effect of carbon dioxide emissions on the global climate from extensive use of fossil fuels and the limited amount of fossil resources has led to an in-depth search for alternative energy systems, primarily based on nuclear or renewable energy sources. Recent innovations in the production of more efficient devices for energy harvesting, storage, and conversion are based on the incorporation of nanostructured materials into electrochemical systems. The aforementioned nano-electrochemical energy systems hold particular promise for alternative energy transportation related technologies including fuel cells, hydrogen storage, and electrochemical supercapacitors. In each of these devices, nanostructured materials can be used to increase the surface area where the critical chemical reactions occur within the same volume and mass, thereby increasing the energy density, power density, electrical efficiency, and physical robustness of the system. Durable corrosion resistant carbon support materials for fuel cells have been designed by adding conductive low cost carbon materials with chemically robust ceramic materials. Since a strict control of the pore size is mandatory to optimize properties for improved performance, chemical activation agents have been utilized as porogens to tune surface areas, pore size distributions, and composition of carbon-based mesoporous materials. Through the use of evaporative self-assembly methods, both randomly disordered and surfactant-templated, ordered carbon-silica nanocomposites have been synthesized with controlled surface area, pore volume, and pore size ranging from 50-800 m2/g, 0.025-0.75 cm3/g, and 2-10 nm, respectively. Multi-walled carbon nanotubes (MWNTs) ranging from 0.05-1.0 wt. % were added to the aforementioned carbon-silica nanocomposites, which provided an additional increase in surface area and improved conductivity. Initially, a conductivity value of 0.0667 S

  6. Nanocomposite Random Lasers

    NASA Astrophysics Data System (ADS)

    Piperaki, K.; Stasinopoulos, A.; Anglos, D.; Anastasiadis, S. H.; Giannelis, E. P.

    2002-11-01

    This report results from a contract tasking FORTH, Foundation for Research & Technology--Hellas as follows: The contractor will synthesize polymer nanocomposite materials and will investigate their properties appropriate to developing a new generation of flexible lasers. The contractor will develop composites by: incorporating semiconductor nanoparticles ZnO, ZnS, ZNSe, and others) into inert polymer matrices; by incorporating high refractive index nanoparticles (TiO2, BaTiO3, and others) into fluorescent conjugated polymers; and by synthesizing nanocomposites using commerically available nonlinear polymers. The contractor will deposit synthesized nanocomposites onto various surfaces and will characterize their dispersion characterisics, viscoelastic properties, and optical properties for lasing.

  7. Ultrahard carbon nanocomposite films

    SciTech Connect

    SIEGAL,MICHAEL P.; TALLANT,DAVID R.; PROVENCIO,PAULA P.; OVERMYER,DONALD L.; SIMPSON,REGINA L.; MARTINEZ-MIRANDA,L.J.

    2000-01-27

    Modest thermal annealing to 600 C of diamondlike amorphous-carbon (a-C) films grown at room temperature results in the formation of carbon nanocomposites with hardness similar to diamond. These nanocomposite films consist of nanometer-sized regions of high density a-C embedded in an a-C matrix with a reduced density of 5--10%. The authors report on the evolution of density and bonding topologies as a function of annealing temperature. Despite a decrease in density, film hardness actually increases {approximately} 15% due to the development of the nanocomposite structure.

  8. Single crystalline mesoporous silicon nanowires

    SciTech Connect

    Hochbaum, A.I.; Gargas, Daniel; Jeong Hwang, Yun; Yang, Peidong

    2009-08-04

    Herein we demonstrate a novel electroless etching synthesis of monolithic, single-crystalline, mesoporous silicon nanowire arrays with a high surface area and luminescent properties consistent with conventional porous silicon materials. These porous nanowires also retain the crystallographic orientation of the wafer from which they are etched. Electron microscopy and diffraction confirm their single-crystallinity and reveal the silicon surrounding the pores is as thin as several nanometers. Confocal fluorescence microscopy showed that the photoluminescence (PL) of these arrays emanate from the nanowires themselves, and their PL spectrum suggests that these arrays may be useful as photocatalytic substrates or active components of nanoscale optoelectronic devices.

  9. Surface texture and physicochemical characterization of mesoporous carbon--wrapped Pd-Fe catalysts for low-temperature CO catalytic oxidation.

    PubMed

    Han, Weiliang; Zhang, Guodong; Zhao, Kun; Lu, Gongxuan; Tang, Zhicheng

    2015-11-21

    In this paper, mesoporous carbon (meso-C) with three-dimensional mesoporous channels was synthesized through a nanocasting route using three-dimensional mesoporous silica KIT-6 as the template. Mesoporous carbon wrapped Pd-Fe nanocomposite catalysts were synthesized by the co-precipitation method. The effects of the experimental conditions, such as pH value, Fe loading content and calcination temperature, on CO oxidation were studied in detail. The prepared Pd-Fe/meso-C catalysts showed excellent catalytic activity after optimizing the experimental conditions. The surface tetravalent Pd content, existing forms of Fe species, surface chemical adsorbed oxygen concentration, and pore channels of mesoporous carbon played vital roles in achieving the highest performance for the Pd-Fe/meso-C catalyst. The reaction pathway was conjectured according to the XPS analysis of the Pd-Fe/meso-C catalysts for CO oxidation, which maybe adhered to the Langmuir-Hinshelwood + redox mechanism. The effect of moisture on CO conversion was investigated, and the superior Pd-Fe/meso-C catalyst could maintain its activity beyond 12 h. This catalyst also showed excellent activity compared to the reported values in the existing literature. PMID:26456796

  10. Synthesis and characterization of mesoporous zirconia and aluminated mesoporous zirconia

    NASA Astrophysics Data System (ADS)

    Zhao, Elizabeth Sun

    Synthesis of mesoporous zirconia has been performed by slowly hydrolyzing zirconium propoxide in the presence of anionic surfactants: namely, dodecyl phosphate or sulfate (P12 and Sf12) and hexadecyl sulfonate (So16) The zirconia. outgassed at 140--150°C has T-plot surface areas higher than 400 M2/g. This outgassing does not remove the surfactant. After calcination in air at 500°C and combustion of the surfactant, the mesoporous volume is reduced by a factor of about 2, whereas the pore wall material crystallizes in the tetragonal phase. The high-resolution electron microscopic study reveals the presence of a disorganized network of polygonal pores structure. It is suggested that the chemistry of the hydrolysis solution is instrumental in determining the pore structure. A schematic model in which the surfactant is a scaffold component is suggested in order to explain these results and the fixation of PO4, or SO4 in the walls may help to preserve the porous structure. It is very different from the templating mechanism. From the density obtained from phase transition temperature, and from the mesoporous volume (N2 adsorption), the thickness of the wall can be calculated as well as the pseudo-length of the pores. From the thickness, the T-plot area can be recalculated and agrees well with the measured T-plot surface area for the sample calcined at 500°C. Around 900°C, the walls become thicker and crystallizes into monoclinic zirconia without pore structure. In order to try to modify, the acidity of the mesoporous sulfated and oxo-phosphated zirconia, they were doped with aluminum. The sulfated zirconia only has a coating layer of amorphous alumina, while the phosphated zirconia has aluminum in the lattice and the alumina coat. A maximum ratio of Al/Zr ˜ 0.04 can be reached in the lattice. The introduction of aluminum into the lattice prevents the crystallization of the oxo-phosphate at 900°C, and helps to preserve the surface area and porosity of the sulfated

  11. Nanocomposite thermite ink

    DOEpatents

    Tappan, Alexander S.; Cesarano, III, Joseph; Stuecker, John N.

    2011-11-01

    A nanocomposite thermite ink for use in inkjet, screen, and gravure printing. Embodiments of this invention do not require separation of the fuel and oxidizer constituents prior to application of the ink to the printed substrate.

  12. Surfactant-Templated Mesoporous Metal Oxide Nanowires

    DOE PAGESBeta

    Luo, Hongmei; Lin, Qianglu; Baber, Stacy; Naalla, Mahesh

    2010-01-01

    We demore » monstrate two approaches to prepare mesoporous metal oxide nanowires by surfactant assembly and nanoconfinement via sol-gel or electrochemical deposition. For example, mesoporous Ta 2 O 5 and zeolite nanowires are prepared by block copolymer Pluronic 123-templated sol-gel method, and mesoporous ZnO nanowires are prepared by electrodeposition in presence of anionic surfactant sodium dodecyl sulfate (SDS) surfactant, in porous membranes. The morphologies of porous nanowires are studied by scanning electron microscopy (SEM) and transmission electron microscopy (TEM) analyses.« less

  13. Nano-composite materials

    DOEpatents

    Lee, Se-Hee; Tracy, C. Edwin; Pitts, J. Roland

    2010-05-25

    Nano-composite materials are disclosed. An exemplary method of producing a nano-composite material may comprise co-sputtering a transition metal and a refractory metal in a reactive atmosphere. The method may also comprise co-depositing a transition metal and a refractory metal composite structure on a substrate. The method may further comprise thermally annealing the deposited transition metal and refractory metal composite structure in a reactive atmosphere.

  14. Multifunctional nanocomposite materials

    SciTech Connect

    Roy, R.; Komarneni, S.

    1991-11-01

    Objective is to examine the low temperature nanocomposite route in the synthesis of multifunctional materials using two-dimensional clays as hosts. After about 8 months, a significant advance was made in the design and synthesis of novel nanocomposite materials, which are nanometal intercalated clays prepared by a low temperature route. A layered V[sub 2]O[sub 5] gel has been made hydrothermally and its cation exchange properties measured. Several pillared clays have also been synthesized and characterized.

  15. Drug Loading of Mesoporous Silicon

    NASA Astrophysics Data System (ADS)

    Moffitt, Anne; Coffer, Jeff; Wang, Mengjia

    2011-03-01

    The nanostructuring of crystalline solids with low aqueous solubilities by their incorporation into mesoporous host materials is one route to improve the bioavailability of such solids. Earlier studies suggest that mesoporous Si (PSi), with pore widths in the range of 5-50 nm, is a candidate for such an approach. In this presentation, we describe efforts to load curcumin into free-standing microparticles of PSi. Curcumin is a compound extracted from turmeric root, which is an ingredient of curry. Curucmin has shown activity against selected cancer cell lines, bacteria, and other medical conditions. However, curcumin has a very low bioavailability due to its extremely low water solubility (0.6 μ g/mL). Incorporation of curcumin was achieved by straightforward loading of the molten solid at 185circ; C. Loading experiments were performed using PSi particles of two different size ranges, 45-75 μ m and 150-250 μ m. Longer loading times and ratio of curcumin to PSi leads to a higher percentage of loaded curcumin in both PSi particle sizes (as determined by weight difference). The extent of curcumin crystallinity was assessed by x-ray diffraction (XRD). The solubility and release kinetics of loaded curcumin from the PSi was determined by extraction into water at 37circ; C, with analysis using UV-VIS spectrometry. NSF-REU and TCU.

  16. ZnFe2O4-TiO2 Nanoparticles within Mesoporous MCM-41

    PubMed Central

    Tang, Aidong; Deng, Yuehua; Jin, Jiao; Yang, Huaming

    2012-01-01

    A novel nanocomposite ZnFe2O4-TiO2/MCM-41 (ZTM) was synthesized by a sol-gel method and characterized through X-ray diffraction (XRD), high-resolution transmission electron microscopy (HRTEM), N2 adsorption-desorption, Raman spectroscopy, and ultraviolet visible (UV-vis) spectrophotometry. The results confirmed the incorporation of ZnFe2O4-TiO2 nanoparticles inside the pores of the mesoporous MCM-41 host without destroying its integrity. ZnFe2O4 nanoparticles can inhibit the transformation of anatase into rutile phase of TiO2. Incorporation of ZnFe2O4-TiO2 within MCM-41 avoided the agglomeration of nanoparticles and reduced the band gap energy of TiO2 to enhance its visible light photocatalytic activity. UV-vis absorption edges of ZTM nanocomposites redshifted with the increase of Zn/Ti molar ratio. The nanocomposite approach could be a potential choice for enhancing the photoactivity of TiO2, indicating an interesting application in the photodegradation and photoelectric fields. PMID:22919325

  17. Mesoporous polyaniline nanofiber decorated graphene micro-flowers for enzyme-less cholesterol biosensors.

    PubMed

    Lakshmi, G B V S; Sharma, Anshu; Solanki, Pratima R; Avasthi, D K

    2016-08-26

    In the present work, we have studied a nanocomposite of polyaniline nanofiber-graphene microflowers (PANInf-GMF), prepared by an in situ rapid mixing polymerization method. The structural and morphological studies of the nanocomposite (PANInf-GMF) were carried out by scanning electron microscopy, transmission electron microscopy, Fourier transform infrared (FTIR) and Raman spectroscopy. The mesoporous, nanofibrous and microflower structures were observed by scanning electron microscopy. The functional groups and synergetic effects were observed by FTIR and micro-Raman measurements. The water wettability was carried out by a contact angle measurement technique and found to be super hydrophilic in nature towards water. This nanocomposite was deposited onto indium-tin-oxide coated glass substrate by a drop casting method and used for the detection of cholesterol using an electrochemical technique. The differential pulse voltammetry studies show the appreciable increase in the current with the addition of 1.93 to 464.04 mg dl(-1) cholesterol concentration. It is also found that the electrodes were highly selective towards cholesterol when compared to other biological interfering analytes, such as glucose, urea, citric acid, cysteine and ascorbic acid. The sensitivity of the sensor is estimated as 0.101 μA mg(-1) dl cm(-2) and the lower detection limit as 1.93 mg dl(-1). This work will throw light on the preparation of non-enzymatic biosensors based on PANInf-carbon nanostructure composites. PMID:27419910

  18. Mesoporous polyaniline nanofiber decorated graphene micro-flowers for enzyme-less cholesterol biosensors

    NASA Astrophysics Data System (ADS)

    Lakshmi, G. B. V. S.; Sharma, Anshu; Solanki, Pratima R.; Avasthi, D. K.

    2016-08-01

    In the present work, we have studied a nanocomposite of polyaniline nanofiber-graphene microflowers (PANInf-GMF), prepared by an in situ rapid mixing polymerization method. The structural and morphological studies of the nanocomposite (PANInf-GMF) were carried out by scanning electron microscopy, transmission electron microscopy, Fourier transform infrared (FTIR) and Raman spectroscopy. The mesoporous, nanofibrous and microflower structures were observed by scanning electron microscopy. The functional groups and synergetic effects were observed by FTIR and micro-Raman measurements. The water wettability was carried out by a contact angle measurement technique and found to be super hydrophilic in nature towards water. This nanocomposite was deposited onto indium-tin-oxide coated glass substrate by a drop casting method and used for the detection of cholesterol using an electrochemical technique. The differential pulse voltammetry studies show the appreciable increase in the current with the addition of 1.93 to 464.04 mg dl‑1 cholesterol concentration. It is also found that the electrodes were highly selective towards cholesterol when compared to other biological interfering analytes, such as glucose, urea, citric acid, cysteine and ascorbic acid. The sensitivity of the sensor is estimated as 0.101 μA mg‑1 dl cm‑2 and the lower detection limit as 1.93 mg dl‑1. This work will throw light on the preparation of non-enzymatic biosensors based on PANInf-carbon nanostructure composites.

  19. Carbon Nanohorns Carried Iron Fluoride Nanocomposite with ultrahigh rate lithium ion storage properties

    NASA Astrophysics Data System (ADS)

    Fan, Lishuang; Li, Bingjiang; Zhang, Naiqing; Sun, Kening

    2015-07-01

    Novel hierarchical carbon nanohorns (CNHs) carried iron fluoride nanocomposites have been constructed by direct growth of FeF3·0.33H2O nanoparticles on CNHs. In the FeF3·0.33H2O@CNHs nanocomposite, the mesopore CNHs play the role as conductive matrix and robust carrier to support the FeF3·0.33H2O nanoparticles. The intimate conductive contact between the two components can build up an express way of electron transfer for rapid Li+ insertion/extraction. The CNHs can not only suppress the growth and agglomeration of FeF3·0.33H2O during the crystallization process, but also sever as an “elastic confinement” to support FeF3·0.33H2O. As was to be expected, the hierarchical FeF3·0.33H2O@CNHs nanocomposite exhibits impressive rate capability and excellent cycle performance. Markedly, the nanocomposite proves stable, ultrahigh rate lithium ion storage properties of 81 mAh g-1 at charge/discharge rate of 50 C (a discharge/charge process only takes 72 s). The integration of high electron conductivity, confined nano sized FeF3·0.33H2O (~5 nm), hierarchical mesopores CNHs and the “elastic confinement” support, the FeF3·0.33H2O@CNHs nanocomposite demonstrates excellent ultrahigh rate capability and good cycling properties.

  20. Carbon Nanohorns Carried Iron Fluoride Nanocomposite with ultrahigh rate lithium ion storage properties

    PubMed Central

    Fan, Lishuang; Li, Bingjiang; Zhang, Naiqing; Sun, Kening

    2015-01-01

    Novel hierarchical carbon nanohorns (CNHs) carried iron fluoride nanocomposites have been constructed by direct growth of FeF3·0.33H2O nanoparticles on CNHs. In the FeF3·0.33H2O@CNHs nanocomposite, the mesopore CNHs play the role as conductive matrix and robust carrier to support the FeF3·0.33H2O nanoparticles. The intimate conductive contact between the two components can build up an express way of electron transfer for rapid Li+ insertion/extraction. The CNHs can not only suppress the growth and agglomeration of FeF3·0.33H2O during the crystallization process, but also sever as an “elastic confinement” to support FeF3·0.33H2O. As was to be expected, the hierarchical FeF3·0.33H2O@CNHs nanocomposite exhibits impressive rate capability and excellent cycle performance. Markedly, the nanocomposite proves stable, ultrahigh rate lithium ion storage properties of 81 mAh g−1 at charge/discharge rate of 50 C (a discharge/charge process only takes 72 s). The integration of high electron conductivity, confined nano sized FeF3·0.33H2O (~5 nm), hierarchical mesopores CNHs and the “elastic confinement” support, the FeF3·0.33H2O@CNHs nanocomposite demonstrates excellent ultrahigh rate capability and good cycling properties. PMID:26173994

  1. Direct imaging Au nanoparticle migration inside mesoporous silica channels.

    PubMed

    Liu, Zhengwang; Che, Renchao; Elzatahry, Ahmed A; Zhao, Dongyuan

    2014-10-28

    Supported metal nanoparticle (NP) catalysts have been widely used in many industry processes and catalytic reactions. Catalyst deactivation is mainly caused by the sintering of supported metal NPs. Hence, understanding the metal NPs' sintering behaviors has great significance in preventing catalyst deactivation. Here we report the metal particle migration inside/between mesochannels by scanning transmission electron microscopy and electron energy loss spectroscopy via an in situ TEM heating technique. A sintering process is proposed that particle migration predominates, driven by the difference of gravitational potential from the height of the uneven internal surface of the mesopores; when the distance of the gold nanoparticles with a size of about 3 and 5 nm becomes short after migration, the coalescence process is completed, which is driven by an "octopus-claw-like" expansion of a conduction electron cloud outside the Au NPs. The supports containing an abundance of micropores help to suppress particle migration and coalescence. Our findings provide the understanding toward the rational design of supported industrial catalysts and other nanocomposites with enhanced activity and stability for applications such as batteries, catalysis, drug delivery, gas sensors, and solar cells. PMID:25264601

  2. Mesoporous Carbon Membranes for Selective Gas Separations

    SciTech Connect

    2009-04-01

    This factsheet describes a study whose focus is on translating a novel class of material developed at Oak Ridge National Laboratory—selfassembled mesoporous carbon—into robust, efficient membrane systems for selective industrial gas separations.

  3. Eu3+, Tb3+/β-diketonate functionalized mesoporous SBA-15/GaN composites: multi-component chemical bonding assembly, characterization, and luminescence.

    PubMed

    Zhao, Yan; Yan, Bing

    2013-04-01

    GaN-functionalized rare earth (Eu3+ and Tb3+) organic/inorganic mesoporous nanocomposites have been successfully synthesized (designated as RE(L-SBA-15)3(L-GaN); RE=Eu, Tb; L=TAA-Si, BTA-Si). The organosilane precursor materials (L-SBA-15) are synthesized by co-condensation of tetraethylorthosilicate (TEOS) and the functionalized β-diketones (TAA-Si and BTA-Si) in the presence of Pluronic P123 surfactant as a template. The modified β-diketones ligands are also used to covalently bond with surface-modified GaN and formed another precursor L-GaN. Both of the precursors can coordinate with rare earth ions to synthesize the final mesoporous materials via a sol-gel process. FTIR, TEM, XRD, and nitrogen (N2) adsorption/desorption measurements are employed to characterize the mesostructure of RE(L-SBA-15)3(L-GaN). The luminescence properties and thermogravimetric analysis of all the prepared materials are characterized in detail, and the results reveal that a series of uniformed mesopore structure hybrid materials has been achieved. The mesoporous material Eu(BTA-Si-SBA-15)3(BTA-Si-GaN) has better luminescence intensity, higher quantum efficiency, and longer lifetime than Eu(TAA-Si-SBA-15)3(TAA-Si-GaN). While the nanocomposite Tb(TAA-Si-SBA-15)3(TAA-Si-GaN) revealed the strongest characteristic emission of Tb ions than Tb(BTASiSBA-15)(BTASiGaN), the excellent luminescent properties and thermal stability enable the hybrid mesoporous material to have potential applications in optical field. PMID:23374434

  4. Location of laccase in ordered mesoporous materials

    NASA Astrophysics Data System (ADS)

    Mayoral, Álvaro; Gascón, Victoria; Blanco, Rosa M.; Márquez-Álvarez, Carlos; Díaz, Isabel

    2014-11-01

    The functionalization with amine groups was developed on the SBA-15, and its effect in the laccase immobilization was compared with that of a Periodic Mesoporous Aminosilica. A method to encapsulate the laccase in situ has now been developed. In this work, spherical aberration (Cs) corrected scanning transmission electron microscopy combined with high angle annular dark field detector and electron energy loss spectroscopy were applied to identify the exact location of the enzyme in the matrix formed by the ordered mesoporous solids.

  5. Mesoporous hybrid organosilica containing urethane moieties

    SciTech Connect

    Seo, You-Kyong; Park, Sung-Bae; Ho Park, Dong . E-mail: chempdh@inje.ac.kr

    2006-04-15

    Mesoporous hybrid material containing urethane moieties in functionalized long chain organic group have been synthesized by using bis[3-(triethoxysilyl) propyl urethane]ethane (BTESPUE) and tetraethoxysilane as structural ingredients. The incorporation of BTESPUE within the framework of mesoporous material was confirmed by Fourier transform-infrared, X-ray photoelectron spectroscopy, solid-state NMR spectroscopy and thermogravimetric analysis. This material had a thick wall and uniform pore, which may be attributed to the hydrogen bonding inside framework due to urethane moieties.

  6. Bragg Reflectors Based on Block Copolymer/Polyhedral Oligomeric Silsesquioxanes (POSS) and TiO2 Hybrid Nanocomposites

    NASA Astrophysics Data System (ADS)

    Li, Cheng; Colella, Nicholas; Watkins, James

    2014-03-01

    Maleamic acid functionalized polyhedral oligomeric silsesquioxanes (POSS) can interact with the poly (ethylene oxide) (PEO) block in Pluronics F108 block copolymer via hydrogen bonding to form well-ordered block copolymer nanocomposites. In this study, the block copolymer composites are spin coated into thin films and maleamic acid groups are thermal crosslinked to stabilize the nanocomposite structure. High temperature calcination of the stabilized nanocomposite yields a robust mesoporous silica thin film. By adjusting the loading of POSS into the block copolymer prior to calcination, the refractive index (RI) of mesoporous silica films can be tuned between 1.13 and 1.18. We show these low RI films can be sequentially layered with hybrid TiO2 nanocomposite films that exhibit a RI of approximately 2.0 to yield efficient Bragg reflectors. The TiO2 films are prepared by the calcinations of polymer/anatase TiO2 nanoparticle composites with NP loadings as high as 90wt%. Due to the porosity existing in each layer, the wavelength of the reflected light is sensitive to the adsorption of solvent vapors such as toluene, isopropanol, and tetrahydrofuran, or analytes, which suggest applications in sensors. Acknowledge The Center for Hierarchical Manufacturing.

  7. In situ microemulsion synthesis of hydroxyapatite-MgFe2O4 nanocomposite as a magnetic drug delivery system.

    PubMed

    Foroughi, Firoozeh; Hassanzadeh-Tabrizi, S A; Bigham, Ashkan

    2016-11-01

    In this study, an innovative synthesis process has been developed to produce hydroxyapatite-magnesium ferrite (HA-MgFe2O4) nanocomposite. In addition, the effect of calcination temperature on drug delivery behavior of produced samples was investigated. HA-MgFe2O4 nanocomposite was prepared via one-step modified reverse microemulsion synthesis route. The resulting products were characterized by X-ray Diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), field emission scanning electron microscopy (FESEM), transmission electron microscopy (TEM), vibrating sample magnetometer (VSM), and Brunauer-Emmett-Teller surface area analysis (BET). The calcined samples at 500 and 700°C demonstrated mesoporous characteristics and large specific surface areas of 88 and 32m(2)/g, respectively. TEM and VSM results showed that the nanocomposite calcined at 700°C has core-shell morphology and a maximum saturation magnetization of 9.47emug(-1). PMID:27524079

  8. Solution-processable phosphorescent to organic light-emitting diodes based on chromophoric amphiphile/silica nanocomposite

    NASA Astrophysics Data System (ADS)

    Yang, Chung-He; Yang, Sheng-Hsiung; Hsu, Chain-Shu

    2009-08-01

    We report the synthesis of a tris-cyclometalated iridium complex which emits sky-blue light and its potential use in phosphorescent light-emitting devices. The hybrid meso-structured nanocomposites by sol-gel co-assembly with tetraethyl ortho-silicate and corresponding molecular interactions within mesopores were also demonstrated. Electroluminescent devices were fabricated using carbazole-based monomers and iridium complex as the active layer, acting as a host/guest system through a co-assembled sol-gel process. Devices based on this nanocomposite showed improved luminescent efficiencies several times higher than that of similar chromophores elaborated in the literature. A triple-layer electroluminescence device with the configuration of ITO/PEDOT/ Ir(F2OC11ppy)3:CA-C11:PBD nanocomposite/TPBI/Ca/Al showed a maximum brightness of 1389 cd m-2 at 12 V and a maximum efficiency of 3.29 cd A-1.

  9. Synthesis, characterization and magnetic behavior of Co/MCM-41 nano-composites

    NASA Astrophysics Data System (ADS)

    Cuello, N.; Elías, V.; Crivello, M.; Oliva, M.; Eimer, G.

    2013-09-01

    Synthesis, structure and magnetic properties of Co/MCM-41 as magnetic nano-composites have been investigated. Mesoporous materials with different degrees of metal loading were prepared by wet impregnation and characterized by ICP, XRD, N2 adsorption, UV-vis DRS, TPR and EPMA-EDS. Cobalt oxide clusters and Co3O4 nano-particles could be confined inside the mesopores of MCM-41, being this fact favored by the Co loading increasing. In addition, larger crystals of Co3O4 detectable by XRD also grow on the surface when the Co loading is enhanced. The magnetic characterization was performed in a SQUID magnetometer using a maximum magnetic applied field µ0Ha=1 T. While the samples with the higher Co loadings showed a behavior typically paramagnetic, a superparamagnetic contribution is more notorious for lower loadings, suggesting high Co species dispersion.

  10. Preparation of irregular mesoporous hydroxyapatite

    SciTech Connect

    Wang Hualin Zhai Linfeng; Li Yanhong; Shi Tiejun

    2008-06-03

    An irregular mesoporous hydroxyapatite (meso-HA), Ca{sub 10}(PO{sub 4}){sub 6}(OH){sub 2}, is successfully prepared from Ca(NO{sub 3}){sub 2}.4H{sub 2}O and NH{sub 4}H{sub 2}PO{sub 4} using surfactant cetyltrimethyl ammonium bromide (CTAB) as template. Fourier transform infrared spectroscopy (FTIR) and differential scanning calorimetry (DSC) results reveal that the positive head of CTAB is assembled on the surface precipitated HA and much NH{sub 4}{sup +} is enclosed in precipitated HA before calcination. Field scanning electron microscope (FSEM) reveals that there exist many interconnected pores throughout the HA reticular skeleton. Nitrogen adsorption-desorption experiment exhibits a mesoporous material type IV curve, and pore size distribution calculated from the desorption branch of the isotherms based on Barrett-Joyner-Halenda (BJH) model shows that most pores throughout the HA reticular skeleton are sized at about 40 nm, but the pores are not uniform on the whole, owning to decomposition of the 'organic' CTAB templating structures and ammonium salt enclosed in the precipitated HA. The specific surface area of irregular meso-HA is calculated to be 37.6 m{sup 2}/g according to the Brunauer-Emmett-Teller (BET) equation. Moreover, after polylactic acid/meso-HA (PLA/meso-HA) composites degraded 12 weeks in normal saline at 37 deg. C, the interconnected pores throughout the HA skeleton were enlarged and sized in micron degree, which resemble trabecular bone structure very much.

  11. Hierarchical multifunctional nanocomposites

    NASA Astrophysics Data System (ADS)

    Ghasemi-Nejhad, Mehrdad N.

    2014-03-01

    Nanocomposites; including nano-materials such as nano-particles, nanoclays, nanofibers, nanotubes, and nanosheets; are of significant importance in the rapidly developing field of nanotechnology. Due to the nanometer size of these inclusions, their physicochemical characteristics differ significantly from those of micron size and bulk materials. The field of nanocomposites involves the study of multiphase materials where at least one of the constituent phases has one dimension less than 100 nm. This is the range where the phenomena associated with the atomic and molecular interaction strongly influence the macroscopic properties of materials. Since the building blocks of nanocomposites are at nanoscale, they have an enormous surface area with numerous interfaces between the two intermix phases. The special properties of the nano-composite arise from the interaction of its phases at the interface and/or interphase regions. By contrast, in a conventional composite based on micrometer sized filler such as carbon fibers, the interfaces between the filler and matrix constitutes have a much smaller surface-to-volume fraction of the bulk materials, and hence influence the properties of the host structure to a much smaller extent. The optimum amount of nanomaterials in the nanocomposites depends on the filler size, shape, homogeneity of particles distribution, and the interfacial bonding properties between the fillers and matrix. The promise of nanocomposites lies in their multifunctionality, i.e., the possibility of realizing unique combination of properties unachievable with traditional materials. The challenges in reaching this promise are tremendous. They include control over the distribution in size and dispersion of the nanosize constituents, and tailoring and understanding the role of interfaces between structurally or chemically dissimilar phases on bulk properties. While the properties of the matrix can be improved by the inclusions of nanomaterials, the

  12. The properties of Gd2O3-assembled silica nanocomposite targeted nanoprobes and their application in MRI.

    PubMed

    Shao, Yuanzhi; Tian, Xiumei; Hu, Wenyong; Zhang, Yongyu; Liu, Huan; He, Haoqiang; Shen, Yingying; Xie, Fukang; Li, Li

    2012-09-01

    The feasibility of the gadolinium-doped mesoporous silica nanocomposite Gd(2)O(3)@MCM-41 as a safe, effective MRI nanoprobe has been validated in the current investigation systematically from atomistic and molecular modeling to its synthesis and characterization on in vivo MR imaging and biocompatibility. The first-principles calculation indicates that it is nearly impossible for toxic Gd ions to dissociate freely from silica. The biocompatibility studies confirm that the nanocomposite is lack of any potential toxicity; the biodistribution studies reveal a greater accumulation of the nanocomposite in liver, spleen, lung and tumor than in kidney, heart and brain; the excretion studies show that the nanocomposite can be cleared nearly 50% via the hepatobiliary transport mechanism after 1.5 months of injection. A larger water proton relaxivity r(1) and a better T(1)-weighted phantom MR imaging capability were detected in the nanocomposite than in the commercially available gadolinium diethylenetriaminepentaacetate. The results demonstrate that the nanocomposite is superior to the commercial counterpart in terms of contrast enhancement with a satisfactory biocompatibility, and it has a high potential to be developed into a safe and effective targeted probe for in vivo molecular imaging of cancer. PMID:22704842

  13. Piezoresistance in Polymer Nanocomposites

    NASA Astrophysics Data System (ADS)

    Rizvi, Reza

    Piezoresistivity in conductive polymer nanocomposites occurs because of the disturbance of particle networks in the polymer matrix. The piezoresistance effect becomes more prominent if the matrix material is compliant making these materials attractive for applications that require flexible force and displacement sensors such as e-textiles and biomechanical measurement devices. However, the exact mechanisms of piezoresistivity including the relationship between the matrix polymer, conductive particle, internal structure and the composite's piezoresistance need to be better understood before it can be applied for such applications. The objective of this thesis is to report on the development of conductive polymer nanocomposites for use as flexible sensors and electrodes. Electrically conductive and piezoresistive nanocomposites were fabricated by a scalable melt compounding process. Particular attention was given to elucidating the role of matrix and filler materials, plastic deformation and porosity on the electrical conduction and piezoresistance. These effects were parametrically investigated through characterizing the morphology, electrical properties, rheological properties, and piezoresistivity of the polymer nanocomposites. The electrical and rheological behavior of the nanocomposites was modeled by the percolation-power law. Furthermore, a model was developed to describe the piezoresistance behavior during plastic deformation in relation to the stress and filler concentration.

  14. Large magnetodielectric effect in composites of Fe2O3·SiO2 nanoglass and mesoporous silica

    NASA Astrophysics Data System (ADS)

    Chatterjee, Soumi; Maiti, Ramaprasad; Saha, Shyamal Kumar; Chakravorty, Dipankar

    2016-06-01

    Composites of Fe2O3·SiO2 nanoglasses and mesoporous silica having a pore diameter of 5.5 nm were synthesized using hydrothermal and sol gel methods. The samples exhibited ferromagnetic behaviour which was the result of antiferromagnetic interaction between Fe2+ and Fe3+ ions in the nanoglass. The nanocomposites showed rather large values of magnetodielectric parameter, the range being 7.9%–51.19% depending on the nanoglass composition and the measuring frequency. The experimental data were satisfactorily fitted to Catalan’s model substantiating the fact that the dielectric permittivity changes were caused by the Maxwell–Wagner space charge polarization arising at the interfaces of the mesoporous silica and the iron-containing Nanosilica glass phase. Also, there were substantial changes in magnetoresistance (in the range 16.79%–33.47%) up to an applied magnetic field of 15 kOe. The large magnetodielectric effect observed in these nanocomposites makes them suitable for application as magnetic sensors.

  15. Chemical and biochemical activities of sonochemically synthesized poly(N-isopropyl acrylamide)/silica nanocomposite

    NASA Astrophysics Data System (ADS)

    Chowdhury, Pranesh; Saha, Swadhin Kr; Guha, Arun; Saha, Samar Kr

    2012-11-01

    Poly(N-isopropyl acrylamide) (PNIPA) grafted mesoporous silica nanoparticles (MPSNP) leading to novel inorganic/organic core-shell nanocomposite has been synthesized sonochemically in an aqueous medium without additives like cross-linker, hydrophobic agent, organic solvent. The colloidal stability of MPSNP is enhanced significantly due to encapsulation of the polymer. The composites are characterized by TEM, FTIR and TGA. The chemical and biochemical activities of the sonochemically synthesized materials have been studied in the light of reaction with acid-base, protein adsorption, antimicrobial activity, biocompatibility and nonthrombogenic property. Advantages of sonochemical synthesis compared to other techniques have been evaluated.

  16. Engineering and characterization of mesoporous silica-coated magnetic particles for mercury removal from industrial effluents

    NASA Astrophysics Data System (ADS)

    Dong, Jie; Xu, Zhenghe; Wang, Feng

    2008-03-01

    Mesoporous silica coatings were synthesized on dense liquid silica-coated magnetite particles using cetyl-trimethyl-ammonium chloride (CTAC) as molecular templates, followed by sol-gel process. A specific surface area of the synthesized particles as high as 150 m 2/g was obtained. After functionalization with mercapto-propyl-trimethoxy-silane (MPTS) through silanation reaction, the particles exhibited high affinity of mercury in aqueous solutions. Atomic force microscopy (AFM), zeta potential measurement, thermal gravimetric analysis (TGA), analytical transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS) and atomic absorption spectroscopy (AAS) were used to characterize the synthesis processes, surface functionalization, and mercury adsorption on the synthesized magnetite particles. The loading capacity of the particles for mercury was determined to be as high as 14 mg/g at pH 2. A unique feature of strong magnetism of the synthesized nanocomposite particles makes the subsequent separation of the magnetic sorbents from complex multiphase suspensions convenient and effective.

  17. Facile mesoporous template-assisted hydrothermal synthesis of ordered mesoporous magnesium silicate as an efficient adsorbent

    NASA Astrophysics Data System (ADS)

    Lu, Qingshan; Li, Qiang; Zhang, Jingjing; Li, Jingfeng; Lu, Jinhua

    2016-01-01

    Mesoporous materials with unique structure as well as special morphology have potential applications in pollutant adsorption. In this work, using mesoporous silica SBA-15 filled with carbon (C@SBA-15) as both silicon source and assisted template, the ordered mesoporous magnesium silicate (Mg3Si4O9(OH)4) has been fabricated at 140 °C by a novel and facile hydrothermal method. During the hydrothermal process, the magnesium silicate grew along the silica walls at the expense of consuming silica and deposited on the carbon surface of the C@SBA-15. Meanwhile, the rigid carbon inside the pores of the SBA-15 supported the magnesium silicate as mesoporous walls under hydrothermal condition. The obtained magnesium silicate possessed ordered mesoporous structure, high specific surface area of 446 m2/g, large pore volume of 0.84 cm3/g, and hierarchical structure assembled with ultrathin nanosheets of 15 nm in thickness. These characteristics endow the ordered mesoporous magnesium silicate with the fast adsorption rate and high adsorption capacity of 382 mg/g for methylene blue. In addition, this synthesis method opens a new approach to fabricate other ordered mesoporous silicates.

  18. Synthesis and visible light photocatalysis of Fe-doped TiO{sub 2} mesoporous layers deposited on hollow glass microbeads

    SciTech Connect

    Cui Lifeng; Wang Yuansheng; Niu Mutong; Chen Guoxin; Cheng Yao

    2009-10-15

    Nano-composite of Fe-doped anatase TiO{sub 2} nanocrystals loaded on the hollow glass microbeads was prepared by co-thermal hydrolysis deposition and calcining treatment. The adherence of TiO{sub 2} mesoporous layers to the surfaces of hollow glass microbeads prevented the aggregation of TiO{sub 2} nanoparticles and benefited to their catalytic activity. The doping of Fe ions makes the absorption edge of the TiO{sub 2} based nano-composite red-shifted into the visible region. An effective photodegradation of the methyl orange aqueous solution was achieved under visible light (lambda>420 nm) irradiation, revealing the potential applicability of such nano-composite in some industry fields, such as air and water purifications. - Graphical abstract: Nano-composite of Fe-doped anatase TiO{sub 2} nanocrystals loaded on the hollow glass microbeads was prepared by co-thermal hydrolysis deposition. Photodegradation of the methyl orange was achieved under visible light irradiation, revealing the potential applicability of such nano-composite in some industry fields.

  19. Corrosion behavior of mesoporous transition metal nitrides

    SciTech Connect

    Yang, Minghui; Allen, Amy J.; Nguyen, Minh T.; Ralston, Walter T.; MacLeod, Michelle J.; DiSalvo, Francis J.

    2013-09-15

    Transition metal nitrides (TMN) have many desirable characteristics such as high hardness and good thermal stability under reducing conditions. This work reports an initial survey of the chemical stability of mesoporous TMNs (TM=Nb, V, Cr and Ti) in water at 80 °C at neutral, acidic and alkaline pH. The mesoporous TMNs had specific surface areas of 25–60 m{sup 2}/g with average pore sizes ranging from 10 to 50 nm. The high surface areas of these materials enhance the rate of corrosion per unit mass over that of a bulk material, making detection of corrosion much easier. The products were characterized by Rietveld refinement of powder X-ray diffraction (PXRD) patterns and by scanning electron microscopy (SEM). Several nitrides have corrosion rates that are, within error, not distinguishable from zero (±1 Å/day). Of the nitrides examined, CrN appears to be the most corrosion resistant under acidic conditions. None of the nitrides studied are corrosion resistant under alkaline conditions. - Graphical abstract: Corrosion behavior of mesoporous transition metal nitrides (TM=Nb, V, Cr and Ti) in acidic and alkaline solutions at 80 °C for 2 weeks. Display Omitted - highlights: • Corrosion rates of mesoporous transition metal nitrides in aqueous solution is reported. • The mesoporous TMNs had surface areas of 25–60 m{sup 2}/g. • CrN is the most corrosion resistant under the conditions studied.

  20. Carbon Nanotube Synthesis Using Mesoporous Silica Templates

    SciTech Connect

    Zheng, Feng; Liang, Liang; Gao, Yufei; Sukamto, Johanes H.; Aardahl, Chris L.

    2002-07-01

    Well-aligned carbon nanotubes (CNTs) were grown on mesoporous silica films by chemical vapor deposition (CVD). Ethylene was used as the carbon source and CVD was performed at 1023 K and atmospheric pressure. The films were doped with Fe during gelation, and three different structure directing agents were used for mesoporous silica synthesis: polyoxyethylene (10) cetyl ether (C16EO10), Pluronic tri-block copolymer (P123), and cetyltriethylammonium chloride (CTAC). A high degree of CNT alignment on C16EO10-mesoporous silica films was produced at Fe:Si molar ratio of 1.80. Similar alignment of CNTs was achieved on the other two types of films but on CTAC-mesoporous silica films, CNTs only grew parallel to the substrate surface from the cracks in the films because of the in-plane arrangement of the mesopores in such films. Considerable progress has been made in producing multi-walled carbon nanotubes (CNTs) by catalytic CVD techniques. If CNTs are to be integrated into certain useful devices, it is critical to be able to grow highly aligned arrays of CNTs with narrow size distribution and at specific locations on a substrate. Long-range alignment normal to the substrate results from steric crowding if the initial catalyst sites are sufficiently dense. Alignment may be improved with better control of the density of catalytic sites by means of a template of appropriate pore structure. The confinement of CNTs by the pores during the initial growth may also help align CNTs.

  1. MnO Nanoparticle@Mesoporous Carbon Composites Grown on Conducting Substrates Featuring High-performance Lithium-ion Battery, Supercapacitor and Sensor

    PubMed Central

    Wang, Tianyu; Peng, Zheng; Wang, Yuhang; Tang, Jing; Zheng, Gengfeng

    2013-01-01

    We demonstrate a facile, two-step coating/calcination approach to grow a uniform MnO nanoparticle@mesoporous carbon (MnO@C) composite on conducting substrates, by direct coating of the Mn-oleate precursor solution without any conducting/binding reagents, and subsequent thermal calcination. The monodispersed, sub-10 nm MnO nanoparticles offer high theoretical energy storage capacities and catalytic properties, and the mesoporous carbon coating allows for enhanced electrolyte transport and charge transfer towards/from MnO surface. In addition, the direct growth and attachment of the MnO@C nanocomposite in the supporting conductive substrates provide much reduced contact resistances and efficient charge transfer. These excellent features allow the use of MnO@C nanocomposites as lithium-ion battery and supercapacitor electrodes for energy storage, with high reversible capacity at large current densities, as well as excellent cycling and mechanical stabilities. Moreover, this MnO@C nanocomposite has also demonstrated a high sensitivity for H2O2 detection, and also exhibited attractive potential for the tumor cell analysis. PMID:24045767

  2. In situ deposition of Prussian blue on mesoporous carbon nanosphere for sensitive electrochemical immunoassay.

    PubMed

    Lai, Guosong; Zhang, Haili; Yu, Aimin; Ju, Huangxian

    2015-12-15

    A Prussian blue (PB) functionalized mesoporous carbon nanosphere (MCN) composite was prepared for loading signal antibody and high-content glucose oxidase (GOD) to obtain a new nanoprobe for sensitive electrochemical immunoassay. The MCN nanocarrier with an average diameter of 180 nm was synthesized by using mesoporous silica nanosphere as a hard template in combination with a hydrothermal carbonization method. This hydrophilic carbon nanomaterial provided an ideal platform for in situ deposition of high-content PB to form the MCN-PB nanocomposite. Based on the step-wise assembly of polyelectrolyte and gold nanoparticles (Au NPs) on the negative-charged nanocomposite, signal antibody and high-content GOD were loaded on this nanocarrier to obtain the nanoprobe. After a sandwich immunoreaction at an Au NPs-modified screen-printed carbon electrode based immunosensor, the nanoprobes were quantitatively captured on the electrode surface to produce sensitive electrochemical response with a PB-mediated GOD catalytic reaction for immunoassay. The high loading of PB and GOD on the nanoprobe greatly amplified the electrochemical signal, leading to the development of a new immunoassay method with high sensitivity. Using human immunoglobulin G as a model analyte, excellent analytical performance including a wide linear range from 0.01 to 100 ng/mL and a low detection limit down to 7.8 pg/mL was obtained. Additionally, the immunosensor showed high specificity, satisfactory stability and repeatability as well as acceptable reliability. The PB-mediated GOD electrochemical system well excluded the conventional interference from the dissolved oxygen. Thus this immunoassay method provides great potentials for practical applications. PMID:26201983

  3. Development of novel mesoporous nanomatrix-supported lipid bilayers for oral sustained delivery of the water-insoluble drug, lovastatin.

    PubMed

    Zhang, Yanzhuo; Zhang, Heran; Che, Erxi; Zhang, Lihua; Han, Jin; Yang, Yihua; Wang, Siling; Zhang, Miao; Gao, Cunqiang

    2015-04-01

    The purpose of this study was to investigate the effect of a core/shell structured nanocomposite, mesoporous nanomatrix-supported lipid bilayer (MN-SLB), as an oral drug nanocarrier, on the dissolution behavior and in vivo absorption of a water-insoluble drug, lovastatin (LOV). The formulation strategy was based on the use of drug-loaded mesoporous silica as the core for the fusion of liposomes. Field emission scanning electron microscopy (FESEM), cryogenic transmission electron microscopy (Cryo-TEM) and nitrogen adsorption were used to systematically characterize the drug carrier and drug-loaded MN-SLB formulation, confirming the successful inclusion of LOV into the nano-pores of MN-SLB. Powder X-ray diffraction (PXRD) and differential scanning calorimetry (DSC) confirmed that the incorporated drug in the carrier was in an amorphous state. An in vitro dissolution study showed that LOV-loaded MN-SLB exhibited a sustained drug release behavior. Compared with the LOV-loaded mesoporous silica particles, LOV-loaded MN-SLB markedly suppressed the burst release. Furthermore, the pharmacokinetics and relative bioavailability of the LOV-loaded MN-SLB formulation was studied in beagle dogs after oral administration and using a commercially available immediate release formulation (Sandoz Lovastatin®) as a reference. It was found that the relative bioavailability of LOV and LOV β-hydroxy acid (LOVA) for the LOV-loaded MN-SLB formulation was 207.2% and 192.1%, respectively. In addition, MN-SLB exhibited negligible toxicity against Caco-2 and HT-29 cells in cytotoxicity assays. The results of this study indicate that the MN-SLB nanocomposite is a promising candidate as a novel oral drug delivery nanovehicle for controlling the dissolution rate and improving the oral absorption of water-insoluble drugs. PMID:25731096

  4. Polyimide/carbon Nanocomposites

    NASA Technical Reports Server (NTRS)

    Harris, Frank W.

    2003-01-01

    The goal of this product is to design and characterize well-defined conductive nanocomposite materials. The materials will be composed of a polymer matrix composed of rigid-backbone polyimides, and will be filled with modified or unmodified multi-walled carbon nanotubes (MWNTs). The ultimate design of this project is to create composite materials with optical clarity and a high conductivity.

  5. Drug release from ordered mesoporous silicas.

    PubMed

    Doadrio, Antonio L; Salinas, Antonio J; Sánchez-Montero, José M; Vallet-Regí, M

    2015-01-01

    The state-of-the-art in the investigation of drugs release from Silica-based ordered Mesoporous Materials (SMMs) is reviewed. First, the SMM systems used like host matrixes are described. Then, the model drugs studied until now, including their pharmacological action, structure and the mesoporous matrix employed for each drug, are comprehensively listed. Next, the factors influencing the release of drugs from SMMs and the strategies used to control the drug delivery, specially the chemical functionalization of the silica surface, are discussed. In addition, how all these factors were gathered in a kinetic equation that describes the drug release from the mesoporous matrixes is explained. The new application of molecular modeling and docking in the investigation of the drug delivery mechanisms from SMMs is also presented. Finally, the new approaches under investigation in this field are mentioned including the design of smart stimuli-responsive materials and other recent proposals for a future investigation. PMID:26549760

  6. Nonenzymatic glucose detection using mesoporous platinum.

    PubMed

    Park, Sejin; Chung, Taek Dong; Kim, Hee Chan

    2003-07-01

    Roughness of nanoscopic dimensions can be used to selectively enhance the faradaic current of a sluggish reaction. Using this principle, we constructed mesoporous structures on the surfaces of pure platinum electrodes responding even more sensitively to glucose than to common interfering species, such as L-ascorbic acid and 4-acetamidophenol. Good sensitivities, as high as 9.6 microA cm(-2) mM(-1), were reproducibly observed in the presence of high concentration of chloride ion. The selectivities, sensitivities, and stabilities determined experimentally have demonstrated the potential of mesoporous platinum as a novel candidate for nonenzymatic glucose sensors. PMID:12964749

  7. Location of laccase in ordered mesoporous materials

    SciTech Connect

    Mayoral, Álvaro; Gascón, Victoria; Blanco, Rosa M.; Márquez-Álvarez, Carlos; Díaz, Isabel

    2014-11-01

    The functionalization with amine groups was developed on the SBA-15, and its effect in the laccase immobilization was compared with that of a Periodic Mesoporous Aminosilica. A method to encapsulate the laccase in situ has now been developed. In this work, spherical aberration (C{sub s}) corrected scanning transmission electron microscopy combined with high angle annular dark field detector and electron energy loss spectroscopy were applied to identify the exact location of the enzyme in the matrix formed by the ordered mesoporous solids.

  8. Orientation specific deposition of mesoporous particles

    NASA Astrophysics Data System (ADS)

    Kjellman, Tomas; Bodén, Niklas; Wennerström, Hâkan; Edler, Karen J.; Alfredsson, Viveka

    2014-11-01

    We present a protocol for a facile orientation specific deposition of plate-like mesoporous SBA-15 silica particles onto a surface (mesopores oriented normal to surface). A drop of an aqueous dispersion of particles is placed on the surface and water vaporizes under controlled relative humidity. Three requirements are essential for uniform coverage: particle dispersion should not contain aggregates, a weak attraction between particles and surface is needed, and evaporation rate should be low. Aggregates are removed by stirring/sonication. Weak attraction is realized by introducing cationic groups to the surface. Insight into the mechanisms of the so-called coffee stain effect is also provided.

  9. A Single-Crystalline Mesoporous Quartz Superlattice.

    PubMed

    Matsuno, Takamichi; Kuroda, Yoshiyuki; Kitahara, Masaki; Shimojima, Atsushi; Wada, Hiroaki; Kuroda, Kazuyuki

    2016-05-10

    There has been significant interest in the crystallization of nanostructured silica into α-quartz because of its physicochemical properties. We demonstrate a single-crystalline mesoporous quartz superlattice, a silica polymorph with unprecedentedly ordered hierarchical structures on both the several tens of nanometers scale and the atomic one. The mesoporous quartz superlattice consists of periodically arranged α-quartz nanospheres whose crystalline axes are mostly oriented in an assembly. The superlattice is prepared by thermal crystallization of amorphous silica nanospheres constituting a colloidal crystal. We found that the deposition of a strong flux of Li(+) only on the surface of silica nanospheres is effective for crystallization. PMID:27060365

  10. Antibiotic loaded carboxymethylcellulose/MCM-41 nanocomposite hydrogel films as potential wound dressing.

    PubMed

    Namazi, Hassan; Rakhshaei, Rasul; Hamishehkar, Hamed; Kafil, Hossein Samadi

    2016-04-01

    Existing wound dressings have disadvantages such as lack of antibacterial activity, insufficient oxygen and water vapor permeability, and poor mechanical properties. Hydrogel-based wound dressings swell several times their dry volume and would be helpful to absorb wound exudates and afford a cooling sensation and a moisture environment. To overcome these hassles, a novel antibiotic-eluting nanocomposite hydrogel was designed via incorporation of mesoporous silica MCM-41 as a nano drug carrier into carboxymethylcellulose hydrogel. Tetracycline and methylene blue as antibacterial agents were loaded to the system and showed different release profiles. The prepared nanocomposite hydrogel was characterized using Fourier transform infrared spectroscopy (FT-IR), X-ray diffractometry (XRD), UV-vis spectroscopy, and scanning electron microscopy (SEM). The prepared nanocomposite hydrogels exhibited an enhanced in vitro swelling, erosion, water vapor and oxygen permeability, and antimicrobial activity. This could effectively increase the time intervals needed to exchange the bandage. The obtained data strongly encourage the use of these nanocomposite hydrogels as wound dressing material. PMID:26740467

  11. Graphene and carbon nanodots in mesoporous materials: an interactive platform for functional applications

    NASA Astrophysics Data System (ADS)

    Innocenzi, Plinio; Malfatti, Luca; Carboni, Davide

    2015-07-01

    The present review is focused on a specific class of nanocomposites obtained through integration of graphene or carbon-based nanomaterials (such as carbon nanodots) with mesoporous inorganic or hybrid materials, obtained via template assisted self-assembly. The task of integrating graphene and carbon nanodots with a self-assembly process is still very challenging and this review shows some of the solutions which have been envisaged so far. These nanocomposite materials are an ideal interactive platform for developing innovative functional applications; they have a high capability of undergoing integration into advanced devices, which well exploits the advantage of tuning the wide properties and flexibility of the soft-chemistry route. A wide range of applications have been developed so far which span from sensing to electronics up to optics and biomedicine. Even though a large number of proof-of-concepts have been reported to date, an even greater expansion of applications in the field is expected to happen in the near future.

  12. A General Method for Constructing Two-Dimensional Layered Mesoporous Mono- and Binary-Transition-Metal Nitride/Graphene as an Ultra-Efficient Support to Enhance Its Catalytic Activity and Durability for Electrocatalytic Application.

    PubMed

    Liu, Baocang; Huo, Lili; Si, Rui; Liu, Jian; Zhang, Jun

    2016-07-27

    We constructed a series of two-dimensional (2D) layered mesoporous mono- and binary-transition-metal nitride/graphene nanocomposites (TMN/G, TM = Ti, Cr, W, Mo, TiCr, TiW, and TiMo) via an efficient and versatile nanocasting strategy for the first time. The 2D layered mesoporous TMN/G is constituted of small TMN nanoparticles composited with graphene nanosheets and has a large surface area with high porosity. Through decoration with well-dispersed Pt nanoparticles, 2D layered mesoporous Pt/TMN/G catalysts can be obtained that display excellent catalytic activity and stability for methanol electro-oxidation reactions (MOR) and oxygen reduction reactions (ORR) in both acidic and alkaline media. The 2D layered mesoporous binary-Pt/TMN/G catalysts possess catalytic activity superior to that of mono-Pt/TMN/G, graphene free Pt/TMN, Pt/G, and Pt/C catalysts. Encouragingly, the 2D layered mesoporous Pt/Ti0.5Cr0.5N/G catalyst exhibits the best electrocatalytic performance for both MOR and ORR. The outstanding electrocatalytic performance of the Pt/Ti0.5Cr0.5N/G catalyst is rooted in its large surface area, high porosity, strong interaction among Pt, Ti0.5Cr0.5N, and graphene, an excellent electron transfer property facilitated by N-doped graphene, and the small size of Pt and Ti0.5Cr0.5N nanocrystals. The outstanding catalytic performance provides the 2D layered mesoporous Pt/Ti0.5Cr0.5N/G catalyst with a wide range of application prospects in direct methanol fuel cells in both acidic and alkaline media. The synthetic method may be available for constructing other 2D layered mesoporous metal nitrides, carbides, and phosphides. PMID:27356463

  13. Hybrid BiOBr-TiO2 nanocomposites with high visible light photocatalytic activity for water treatment.

    PubMed

    Wei, Xian-Xian; Cui, Haitao; Guo, Shaoqing; Zhao, Liangfu; Li, Wen

    2013-12-15

    Novel highly active visible light photocatalysts BiOBr-TiO2 nanocomposites were prepared by a facile one-pot solvothermal approach. Series of characterizations verified that the BiOBr nanoscale crystals are highly dispersed in amorphous TiO2 to form the hybrid mesoporous structure. The material shows excellent photocatalytic performance towards photodegradation of Rhodamine B under visible light irradiation. The content ratio between TiO2 and BiOBr plays a key role in the microstructure of the nanocomposites, so as to result in distinguished photocatalytic activity. The sample with a molar ratio of 10 between TiO2 and BiOBr shows the optimum performance. The high photocatalytic activity of BiOBr-TiO2 nanocomposites under visible light could be ascribed to the large surface area, opened mesoporous structure, appropriate band-gap, as well as synergistic effect between TiO2 and BiOBr. Besides, the BiOBr-TiO2 composites render a facile separation due to the three-dimensional superstructure. The BiOBr-TiO2 photocatalyst is very promising for water purification as well as other environmental applications. PMID:24220195

  14. Highly Thermal Conductive Nanocomposites

    NASA Technical Reports Server (NTRS)

    Sun, Ya-Ping (Inventor); Connell, John W. (Inventor); Veca, Lucia Monica (Inventor)

    2015-01-01

    Disclosed are methods for forming carbon-based fillers as may be utilized in forming highly thermal conductive nanocomposite materials. Formation methods include treatment of an expanded graphite with an alcohol/water mixture followed by further exfoliation of the graphite to form extremely thin carbon nanosheets that are on the order of between about 2 and about 10 nanometers in thickness. Disclosed carbon nanosheets can be functionalized and/or can be incorporated in nanocomposites with extremely high thermal conductivities. Disclosed methods and materials can prove highly valuable in many technological applications including, for instance, in formation of heat management materials for protective clothing and as may be useful in space exploration or in others that require efficient yet light-weight and flexible thermal management solutions.

  15. Multifunctional reactive nanocomposite materials

    NASA Astrophysics Data System (ADS)

    Stamatis, Demitrios

    Many multifunctional nanocomposite materials have been developed for use in propellants, explosives, pyrotechnics, and reactive structures. These materials exhibit high reaction rates due to their developed reaction interfacial area. Two applications addressed in this work include nanocomposite powders prepared by arrested reactive milling (ARM) for burn rate modifiers and reactive structures. In burn rate modifiers, addition of reactive nanocomposite powders to aluminized propellants increases the burn rate of aluminum and thus the overall reaction rate of an energetic formulation. Replacing only a small fraction of aluminum by 8Al·MoO3 and 2B·Ti nanocomposite powders enhances the reaction rate with little change to the thermodynamic performance of the formulation; both the rate of pressure rise and maximum pressure measured in the constant volume explosion test increase. For reactive structures, nanocomposite powders with bulk compositions of 8Al·MoO3, 12Al·MoO3, and 8Al·3CuO were prepared by ARM and consolidated using a uniaxial die. Consolidated samples had densities greater than 90% of theoretical maximum density while maintaining their high reactivity. Pellets prepared using 8Al·MoO3 powders were ignited by a CO2 laser. Ignition delays increased at lower laser powers and greater pellet densities. A simplified numerical model describing heating and thermal initiation of the reactive pellets predicted adequately the observed effects of both laser power and pellet density on the measured ignition delays. To investigate the reaction mechanisms in nanocomposite thermites, two types of nanocomposite reactive materials with the same bulk compositions 8Al·MoO3 were prepared by different methods. One of the materials was manufactured by ARM and the other, so called metastable interstitial composite (MIC), by mixing of nano-scaled individual powders. Clear differences in the low-temperature redox reactions, welldetectable by differential scanning calorimetry

  16. Nanocomposites and bone regeneration

    NASA Astrophysics Data System (ADS)

    James, Roshan; Deng, Meng; Laurencin, Cato T.; Kumbar, Sangamesh G.

    2011-12-01

    This manuscript focuses on bone repair/regeneration using tissue engineering strategies, and highlights nanobiotechnology developments leading to novel nanocomposite systems. About 6.5 million fractures occur annually in USA, and about 550,000 of these individual cases required the application of a bone graft. Autogenous and allogenous bone have been most widely used for bone graft based therapies; however, there are significant problems such as donor shortage and risk of infection. Alternatives using synthetic and natural biomaterials have been developed, and some are commercially available for clinical applications requiring bone grafts. However, it remains a great challenge to design an ideal synthetic graft that very closely mimics the bone tissue structurally, and can modulate the desired function in osteoblast and progenitor cell populations. Nanobiomaterials, specifically nanocomposites composed of hydroxyapatite (HA) and/or collagen are extremely promising graft substitutes. The biocomposites can be fabricated to mimic the material composition of native bone tissue, and additionally, when using nano-HA (reduced grain size), one mimics the structural arrangement of native bone. A good understanding of bone biology and structure is critical to development of bone mimicking graft substitutes. HA and collagen exhibit excellent osteoconductive properties which can further modulate the regenerative/healing process following fracture injury. Combining with other polymeric biomaterials will reinforce the mechanical properties thus making the novel nano-HA based composites comparable to human bone. We report on recent studies using nanocomposites that have been fabricated as particles and nanofibers for regeneration of segmental bone defects. The research in nanocomposites, highlight a pivotal role in the future development of an ideal orthopaedic implant device, however further significant advancements are necessary to achieve clinical use.

  17. Multilayer graphene rubber nanocomposites

    NASA Astrophysics Data System (ADS)

    Schartel, Bernhard; Frasca, Daniele; Schulze, Dietmar; Wachtendorf, Volker; Krafft, Bernd; Morys, Michael; Böhning, Martin; Rybak, Thomas

    2016-05-01

    Multilayer Graphene (MLG), a nanoparticle with a specific surface of BET = 250 m2/g and thus made of only approximately 10 graphene sheets, is proposed as a nanofiller for rubbers. When homogenously dispersed, it works at low loadings enabling the replacement of carbon black (CB), increase in efficiency, or reduction in filler concentration. Actually the appropriate preparation yielded nanocomposites in which just 3 phr are sufficient to significantly improve the rheological, curing and mechanical properties of different rubbers, as shown for Chlorine-Isobutylene-Isoprene Rubber (CIIR), Nitrile-Butadiene Rubber (NBR), Natural Rubber (NR), and Styrene-Butadiene Rubber (SBR). A mere 3 phr of MLG tripled the Young's modulus of CIIR, an effect equivalent to 20 phr of carbon black. Similar equivalents are observed for MLG/CB mixtures. MLG reduces gas permeability, increases thermal and electrical conductivities, and retards fire behavior. The later shown by the reduction in heat release rate in the cone calorimeter. The higher the nanofiller concentration is (3 phr, 5 phr, and 10 phr was investigated), the greater the improvement in the properties of the nanocomposites. Moreover, the MLG nanocomposites improve stability of mechanical properties against weathering. An increase in UV-absorption as well as a pronounced radical scavenging are proposed and were proved experimentally. To sum up, MLG is interesting as a multifunctional nanofiller and seems to be quite ready for rubber development.

  18. Metal-Polymer Nanocomposites

    NASA Astrophysics Data System (ADS)

    Nicolais, Luigi; Carotenuto, Gianfranco

    2004-09-01

    A unique guide to an essential area of nanoscience Interest in nano-sized metals has increased greatly due to their special characteristics and suitability for a number of advanced applications. As technology becomes more refined-including the ability to effectively manipulate and stabilize metals at the nanoscale-these materials present ever-more workable solutions to a growing range of problems. Metal-Polymer Nanocomposites provides the first guide solely devoted to the unique properties and applications of this essential area of nanoscience. It offers a truly multidisciplinary approach, making the text accessible to readers in physical, chemical, and materials science as well as areas such as engineering and topology. The thorough coverage includes: * The chemical and physical properties of nano-sized metals * Different approaches to the synthesis of metal-polymer nanocomposites (MPN) * Advanced characterization techniques and methods for study of MPN * Real-world applications, including color filters, polarizers, optical sensors, nonlinear optical devices, and more * An extensive list of references on the topics covered A unique, cutting-edge resource for a vital area of nanoscience development, Metal-Polymer Nanocomposites is an invaluable text for students and practitioners of materials science, engineering, polymer science, chemical engineering, electrical engineering, and optics.

  19. Synthesis and characterization of MnWO4 nanoparticles encapsulated in mesoporous silica SBA-15 by fast microwave-assisted method

    NASA Astrophysics Data System (ADS)

    Hoang, Luc Huy; Hanh, Pham Van; Phu, Nguyen Dang; Chen, Xiang-Bai; Chou, Wu Ching

    2015-02-01

    The MnWO4 nanoparticles encapsulated in mesoporous silica (MnWO4/SBA-15) was successfully synthesized by a fast microwave-assisted method. The products were characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), nitrogen absorption-desorption isotherm, and Fourier transform infrared spectroscopy (FTIR). Our results showed that the MnWO4/SBA-15 nanocomposites have the ordered hexagonal meso-structure of SBA-15, indicating MnWO4 nanoparticles were successfully distributed into the channels of SBA-15. The size of MnWO4 nanoparticles in SBA-15 is significantly smaller than the size of MnWO4 nanoparticles prepared without SBA-15, indicating that the MnWO4/SBA15 nanocomposites would be very promising for improving photocatalytic activity of MnWO4 nanoparticles.

  20. Superior electrochemical properties of manganese dioxide/reduced graphene oxide nanocomposites as anode materials for high-performance lithium ion batteries

    NASA Astrophysics Data System (ADS)

    Lee, Suk-Woo; Lee, Chang-Wook; Yoon, Seung-Beom; Kim, Myeong-Seong; Jeong, Jun Hui; Nam, Kyung-Wan; Roh, Kwang Chul; Kim, Kwang-Bum

    2016-04-01

    MnO2/reduced graphene oxide (rGO) nanocomposites were synthesized via a simple solution method at room temperature for use in Li-ion batteries. Owing to the mesoporous features as well as the high electrical conductivity of rGO, the overall electronic and ionic conductivities of the nanocomposite were increased, resulting in improved electrochemical properties in terms of specific capacity, rate capability, and cyclability. In particular, as-prepared nanocomposites showed 222 and 115 mAh g-1 at a current density of as high as 5 and 10 A g-1, and the specific capacitance was well maintained after 400 cycles. In addition, MnO2, via composite formation with rGO, permitted the additional conversion reaction between MnO and Mn3O4, resulting in the reduction of the initial irreversible capacity despite the high first discharge capacity caused by the large specific surface area.

  1. Mesoporous Silica Nanomaterials for Applications in Catalysis, Sensing, Drug Delivery and Gene Transfection

    SciTech Connect

    Daniela Rodica Radu

    2005-12-19

    The central theme of this dissertation is represented by the versatility of mesoporous silica nanomaterials in various applications such as catalysis and bio-applications, with main focus on biological applications of Mesoporous Silica Nanospheres (MSN). The metamorphosis that we impose to these materials from catalysis to sensing and to drug and gene delivery is detailed in this dissertation. First, we developed a synthetic method that can fine tune the amount of chemically accessible organic functional groups on the pores surface of MSN by exploiting electrostatic and size matching between the cationic alkylammonium head group of the cetyltrimethylammonium bromide (CTAB) surfactant and various anionic organoalkoxysilane precursors at the micelle-water interface in a base-catalyzed condensation reaction of silicate. Aiming nature imitation, we demonstrated the catalytic abilities of the MSNs, We utilized an ethylenediamine functional group for chelating Cu{sup 2+} as a catalytic functional group anchored inside the mesopores. Thus, a polyalkynylene-based conducting polymer (molecular wire) was synthesized within the Cu-functionalized MSNs silica catalyst. For sensing applications, we have synthesized a poly(lactic acid) coated mesoporous silica nanosphere (PLA-MSN) material that serves as a fluorescence sensor system for detection of amino-containing neurotransmitters in neutral aqueous buffer. We exploited the mesoporosity of MSNs for encapsulating pharmaceutical drugs. We examined bio-friendly capping molecules such as polyamidoamine dendrimers of generations G2 to G4, to prevent the drug leaching. Next, the drug delivery system employed MSNs loaded with Doxorubicin, an anticancer drug. The results demonstrated that these nano-Trojan horses have ability to deliver Doxorubicin to cancer cells and induce their death. Finally, to demonstrate the potential of MSN as an universal cellular transmembrane nanovehicle, we anchored positively charged dendrimers on the

  2. Thermoset-Based Nanocomposites

    NASA Astrophysics Data System (ADS)

    Bhembe, Pele

    2002-03-01

    The field of polymer-Clay nanocomposites has attracted considerable attention as a method of enhancing polymer properties and extending their utility, by using molecular or nanoscale reinforcements rather than conventional particulate field microcomposites. Layered silicates dispersed as a reinforcing phase in a polymer matrix are one of the most important forms of such inorganic-organic nanocomposites, making them the subject of intense research. While a significant amount of work has been published on thermoplastic based nanocomposites, however, comparatively few studies of thermoset-based systems have been published. Thus, our research is centered on elucidating the structure-property relationships of thermoset-based nanocomposites. We have developed a series of layered silicate/thermoset nanocomposites using several thermoset polymers (epoxies(di and tetrafunctional), cyanate esters and PMR-15 polyimide). Wide angle X-ray diffraction suggests that intercalated morphologies were obtained for the cases studied. The glass transition temperature has been found to vary as the organic modifier and its amount is varied. For difunctional epoxy samples dispersed with Cloisite 30B, a commercially available nanoclay, the Tg increased by twenty degrees upon addition of as little as 2viscoelastic behavior of these materials has also been investigated using dynamic mechanical analysis. A modest increase in the glassy storage modulus was obtained as the amount of nanoclay increased, with a significant increase in the plateau modulus. Additionally, master curves have been generated using time-temperature superposition, allowing further analysis of the effect of the nanoclay on the relaxation behavior. Activation energies calculated from Arrhenius plots increase as the clay contents increase. These effects will be discussed in the presentation. The fracture toughness increased upon addition of nanoclays while the CTE decreased. Interestingly, the onset of decomposition

  3. Nanocomposite hydrogels for biomedical applications

    PubMed Central

    Gaharwar, Akhilesh K.

    2014-01-01

    Hydrogels mimic native tissue microenvironment due to their porous and hydrated molecular structure. An emerging approach to reinforce polymeric hydrogels and to include multiple functionalities focuses on incorporating nanoparticles within the hydrogel network. A wide range of nanoparticles, such as carbon-based, polymeric, ceramic, and metallic nanomaterials can be integrated within the hydrogel networks to obtain nanocomposites with superior properties and tailored functionality. Nanocomposite hydrogels can be engineered to possess superior physical, chemical, electrical, and biological properties. This review focuses on the most recent developments in the field of nanocomposite hydrogels with emphasis on biomedical and pharmaceutical applications. In particular, we discuss synthesis and fabrication of nanocomposite hydrogels, examine their current limitations and conclude with future directions in designing more advanced nanocomposite hydrogels for biomedical and biotechnological applications. PMID:24264728

  4. Functionalized bimodal mesoporous silicas as carriers for controlled aspirin delivery

    NASA Astrophysics Data System (ADS)

    Gao, Lin; Sun, Jihong; Li, Yuzhen

    2011-08-01

    The bimodal mesoporous silica modified with 3-aminopropyltriethoxysilane was performed as the aspirin carrier. The samples' structure, drug loading and release profiles were characterized with X-ray diffraction, scanning electron microscopy, N 2 adsorption and desorption, Fourier transform infrared spectroscopy, TG analysis, elemental analysis and UV-spectrophotometer. For further exploring the effects of the bimodal mesopores on the drug delivery behavior, the unimodal mesoporous material MCM-41 was also modified as the aspirin carrier. Meantime, Korsmeyer-Peppas equation ft= ktn was employed to analyze the dissolution data in details. It is indicated that the bimodal mesopores are beneficial for unrestricted drug molecules diffusing and therefore lead to a higher loading and faster releasing than that of MCM-41. The results show that the aspirin delivery properties are influenced considerably by the mesoporous matrix, whereas the large pore of bimodal mesoporous silica is the key point for the improved controlled-release properties.

  5. Electrical Relaxation in ULTEM® and ULTEM® Containing Mesoporous Silica

    NASA Astrophysics Data System (ADS)

    Turo, Andrew; Edmondson, Charles E.; Lomax, Joseph F.; Bendler, John T.; Fontanella, John J.; Wintersgill, Mary C.

    2008-08-01

    Mesoporous silica has been added to Ultem® 1000 polyetherimide using solution casting. The mesoporous silica that was added was either uncoated or coated with polystyrene. Audio frequency dielectric relaxation studies were then carried out over the temperature range 5.5 to 550 K. Several interesting results were obtained. First, the uncoated mesoporous silica caused essentially no change in the relaxation spectrum of pure Ultem®. The polystyrene coated mesoporous silica caused rather large changes. The most striking example is the introduction of a new relaxation. This relaxation occurs at about 150 K and 1000 Hz as showing in fig. 1 via the open circles.

  6. Surface functionalized mesoporous material and method of making same

    DOEpatents

    Feng, Xiangdong [West Richland, WA; Liu, Jun [West Richland, WA; Fryxell, Glen E [Kennewick, WA

    2001-12-04

    According to the present invention, an organized assembly of functional molecules with specific interfacial functionality (functional group(s)) is attached to available surfaces including within mesopores of a mesoporous material. The method of the present invention avoids the standard base soak that would digest the walls between the mesopores by boiling the mesoporous material in water for surface preparation then removing all but one or two layers of water molecules on the internal surface of a pore. Suitable functional molecule precursor is then applied to permeate the hydrated pores and the precursor then undergoes condensation to form the functional molecules on the interior surface(s) of the pore(s).

  7. An introduction to polymer nanocomposites

    NASA Astrophysics Data System (ADS)

    Armstrong, Gordon

    2015-11-01

    This review presents an overview of the formulation, characterization and range of applications for polymer nanocomposites. After explaining how material properties at the nanometre scale can vary compared to those observed at longer length scales, typical methods used to formulate and characterize nanocomposites at laboratory and industrial scale will be described. The range of mechanical, electrical and thermal properties obtainable from nanocomposite materials, with examples of current commercial applications, will be outlined. Formulation and characterization of nanoparticle, nanotube and graphene composites will be discussed by reference to nanoclay-based composites, as the latter are presently of most technological relevance. Three brief case studies are presented to demonstrate how structure/property relationships may be controlled in a variety of polymer nanocomposite systems to achieve required performance in a given application. The review will conclude by discussing potential obstacles to commercial uptake of polymer nanocomposites, such as inconsistent protocols to characterize nanocomposites, cost/performance balances, raw material availability, and emerging legislation, and will conclude by discussing the outlook for future development and commercial uptake of polymer nanocomposites.

  8. Synthesis of periodic mesoporous silica thin films

    SciTech Connect

    Anderson, M.T.; Martin, J.E.; Odinek, J.G.; Newcomer, P.

    1996-06-01

    We have synthesized periodic mesoporous silica thin films from homogeneous solutions. To synthesize the films, a thin layer of a pH 7 micellar coating solution that contains TMOS (tetramethoxysilane) is dip or spin-coated onto Si wafers, borosilicate glass, or quartz substrates. NH3 gas is diffused into the solution and causes rapid hydrolysis and condensation of the TMOS and the formation of periodic mesoporous thin films within 10 seconds. Combination of homogenous solutions and rapid product formation maximizes the concentration of the desired product and provides a controlled, predictable microstructure. The films have been made continuous and crack-free by optimizing initial silica concentration and film thickness. The films are being evaluated as high surface area, size-selective coatings for surface acoustic wave (SAW) sensors.

  9. Polyamide 6/Layered Silicate Nanocomposites

    NASA Astrophysics Data System (ADS)

    Dębowska, M.; Rudzińska-Girulska, J.; Pigłowski, J.; Dołęga, J.

    2008-05-01

    Polyamide 6 (PA6) and its two exfoliated nanocomposites (PA6/Nf919 and PA6/BZ-COCO), with bentonite (2.5 wt.%) organophilically treated with different cations, were studied. Improved mechanical properties, changes in crystallinity and morphology as well as higher glass transition temperature values were observed for the nanocomposites in comparison to the neat PA6. For the nanocomposite PA6/BZ-COCO, of better surface modification of platelets and better interaction between the polymeric matrix and the organobentonite, higher values of Young's modulus and yielding point together with higher contribution of larger free volume holes to free volume distributions occurred.

  10. The Synthesis of Functional Mesoporous Materials

    SciTech Connect

    Fryxell, Glen E.

    2006-11-01

    The ability to decorate a silica surface with specific ligand fields and/or metal complexes creates powerful new capabilities for catalysis, chemical separations and sensor development. Integrating this with the ability to control the spacing of these complexes across the surface, as well as the symmetry and size of the pore structure, allows the synthetic chemist to hierarchically tailor these structured nanomaterials to specific needs. The next step up the “scale ladder” is provided by the ability to coat these mesoporous materials onto complex shapes, allowing for the intimate integration of these tailored materials into device interfaces. The ability to tailor the pore structure of these mesoporous supports is derived from the surfactant templated synthesis of mesoporous materials, an area which has seen an explosion of activity over the last decade.[1,2] The ability to decorate the surface with the desired functionality requires chemical modification of the oxide interface, most commonly achieved using organosilane self-assembly.[3-6] This manuscript describes recent results from the confluence of these two research areas, with a focus on synthetic manipulation of the morphology and chemistry of the interface, with the ultimate goal of binding metal centers in a chemically useful manner.

  11. Mesoporous silica nanoparticles for active corrosion protection.

    PubMed

    Borisova, Dimitriya; Möhwald, Helmuth; Shchukin, Dmitry G

    2011-03-22

    This work presents the synthesis of monodisperse, mesoporous silica nanoparticles and their application as nanocontainers loaded with corrosion inhibitor (1H-benzotriazole (BTA)) and embedded in hybrid SiOx/ZrOx sol-gel coating for the corrosion protection of aluminum alloy. The developed porous system of mechanically stable silica nanoparticles exhibits high surface area (∼1000 m2·g(-1)), narrow pore size distribution (d∼3 nm), and large pore volume (∼1 mL·g(-1)). As a result, a sufficiently high uptake and storage of the corrosion inhibitor in the mesoporous nanocontainers was achieved. The successful embedding and homogeneous distribution of the BTA-loaded monodisperse silica nanocontainers in the passive anticorrosive SiOx/ZrOx film improve the wet corrosion resistance of the aluminum alloy AA2024 in 0.1 M sodium chloride solution. The enhanced corrosion protection of this newly developed active system in comparison to the passive sol-gel coating was observed during a simulated corrosion process by the scanning vibrating electrode technique (SVET). These results, as well as the controlled pH-dependent release of BTA from the mesoporous silica nanocontainers without additional polyelectrolyte shell, suggest an inhibitor release triggered by the corrosion process leading to a self-healing effect. PMID:21344888

  12. Mesoporous carbon nanomaterials as environmental adsorbents.

    PubMed

    Tripathi, Pranav K; Gan, Lihua; Liu, Mingxian; Rao, Nageswara N

    2014-02-01

    The transportation and diffusion of the guest objects or molecules in the porous carbon nanomaterials can be facilitated by reducing the pathway and resistance. The reduced pathway depends on the porous nature of carbon nanomaterials. Classification of porous carbon materials by the International Union of Pure and Applied Chemistry (IUPAC) has given a new opportunity to design the pores as per their applicability and to understand the mobility of ions, atoms, and molecules in the porous network of carbon materials and also advanced their countless applicability. However, synthesis of carbon nanomaterials with a desired porous network is still a great challenge. Although, remarkable developments have taken place in the recent years, control over the pores size and/or hierarchical porous architectures, especially in the synthesis of carbon nanospheres (CNSs) and ordered mesoporous carbon (OMCs) is still intriguing. The micro and mesoporous CNSs and OMCs have been prepared by a variety of procedures and over a wide range of compositions using various different surfactant templates and carbon precursors etc. The mechanisms of formation of micromesopore in the CNSs and OMCs are still evolving. On the other hand, the urge for adsorbents with very high adsorption capacities for removing contaminants from water is growing steadily. In this review, we address the state-of-the-art synthesis of micro and mesoporous CNSs and OMCs, giving examples of their applications for adsorptive removals of contaminants including our own research studies. PMID:24749459

  13. Polymer/mesoporous metal oxide composites

    NASA Astrophysics Data System (ADS)

    Ver Meer, Melissa Ann

    Understanding the nature of the interfacial region between an organic polymer matrix and an inorganic filler component is essential in determining how this region impacts the overall bulk properties of the organic/inorganic hybrid composite material. In this work, polystyrene was used as the model polymer matrix coupled with silica-based filler materials to investigate the nature of structure-property relationships in polymer composites. Initial work was conducted on synthesis and characterization of colloidal and mesoporous silica particles melt blended into the polystyrene matrix. Modification of the interface was accomplished by chemically bonding the silica particles with the polystyrene chains through polymerization from the particle surface via atom transfer radical polymerization. High molecular weight polystyrene chains were formed and bulk test samples were evaluated with increased thermal stability of the grafted polymer composite system versus equivalent melt blended polymer composites. Polymer grafting was also conducted from the internal pores of mesoporous silica, further improving the thermal stability of the composite system without degrading dynamic mechanical properties. Characterization of the polymer composites was conducted with gel permeation chromatography, transmission electron microscopy, thermogravimetric analysis and dynamic mechanical analysis. It was also discovered during the polystyrene-silica composite studies that amorphous polystyrene can possess a less mobile phase, evident in a second peak of the loss tangent (tan delta). The long annealing times necessitated by the mesoporous silica composites were replicated in as received polystyrene. This new, less mobile phase is of particular interest in determining the mobility of polymer chains in the interfacial region.

  14. Nanocomposite for radiation detection

    NASA Astrophysics Data System (ADS)

    Sahi, Sunil

    2012-02-01

    Cerium fluoride is among the widely studied inorganic scintillators for radiation detection, because of its high light output and high stopping power. Herein, platelets shape CeF3 nanoparticles for radiation detection was synthesis by bisolvent solvothermal method. The characterization of nanoprticles was done by photoluminescence, XRD and SEM measurement. The synthesized CeF3 nanoparticles have broad emission peak around 330 nm. ZnO is a semiconductor scintillator, having fast decay time. ZnO nanoparticles were synthesized using solvothermal method and UV-Vis, photoluminescence and SEM measurement were done for their characterization. The absorption spectrum of the ZnO nanoparticles is dependent on the size of the nanoparticles. By changing the temperature and the concentration of zinc salt and surfactant, ZnO with absorption spectra overlapping with the emission spectra of CeF3 were made for the purpose of creating nanocomposites, with improved scintillation properties. The energy transfer between two nanoparticles was also studied and the changes in Photoluminescence intensity of the nanocomposites were described.

  15. Peptide-Decorated Gold Nanoparticles as Functional Nano-Capping Agent of Mesoporous Silica Container for Targeting Drug Delivery.

    PubMed

    Chen, Ganchao; Xie, Yusheng; Peltier, Raoul; Lei, Haipeng; Wang, Ping; Chen, Jun; Hu, Yi; Wang, Feng; Yao, Xi; Sun, Hongyan

    2016-05-11

    A stimuli-responsive drug delivery system (DDS) with bioactive surface is constructed by end-capping mesoporous silica nanoparticles (MSNs) with functional peptide-coated gold nanoparticles (GNPs). MSNs are first functionalized with acid-labile α-amide-β-carboxyl groups to carry negative charges, and then capped with positively charged GNPs that are decorated with oligo-lysine-containing peptide. The resulting hybrid delivery system exhibits endo/lysosomal pH triggered drug release, and the incorporation of RGD peptide facilitates targeting delivery to αvβ3 integrin overexpressing cancer cells. The system can serve as a platform for preparing diversified multifunctional nanocomposites using various functional inorganic nanoparticles and bioactive peptides. PMID:27102225

  16. Phosphorylated Mesoporous Carbon as a Solid Acid Catalyst

    SciTech Connect

    Dai, Sheng; Mayes, Richard T; Fulvio, Pasquale F; Ma, Zhen

    2011-01-01

    Mesoporous carbon catalyst supports are attractive due to their wide chemical stability while potentially increasing masstransport through and providing a path for larger molecules to access catalytic sites. Herein we report the synthesis of a 10 phosphorylated mesoporous carbon solid-acid catalyst characterized by NH3-TPD and isopropanol dehydration.

  17. Protection of Organic Matter from Enzyme Degradation by Mineral Mesopores

    NASA Astrophysics Data System (ADS)

    Zimmerman, A. R.; Chorover, J. D.; Brantley, S. L.

    2003-12-01

    Mineral mesopores (2-50 nm diameter) may sequester organic matter (natural and pollutant) and protect it from microbial and fungal enzymatic degradation in soils and sediments. Synthetic mesoporous alumina and silica minerals with uniform pore sizes and shapes were used to test the role of mesopores in protecting organic matter from enzymatic degradation. A model humic compound, L-3-4-dihydroxyphenylalanine (L-DOPA), was sorbed to the internal surfaces of mesoporous alumina (8.2 nm diameter pores) and mesoporous silica (3.4 nm diameter pores) as well as to the external surfaces of nonporous alumina and silica analogues. A fungal derived enzyme, laccase, was added to these sorbate-sorbent pairs in aqueous solution and activity was monitored by oxygen consumption. Though enzyme activity was suppressed in both cases by mineral-enzyme interaction (enzyme inhibition likely due to adsorption of the enzyme), both the rate and total extent of enzyme-mediated degradation of mesopore-sorbed L-DOPA was 3-40 times lower than that of the externally-sorbed analogue. These results provide, for the first time, direct evidence for the viability of the proposed mesopore protection mechanism for the sequestration and preservation of sedimentary organic matter and organic contaminants. Mesopore adsorption/desorption phenomena may also help explain the slow degradation of organic contaminants in soil and sediment and may prove useful as delivery vehicles for organic compounds to agricultural, medical or environmental systems.

  18. Transport properties of fast proton conducting mesoporous silica xerogels

    NASA Astrophysics Data System (ADS)

    Colomer, M. T.; Rubio, F.; Jurado, J. R.

    Mesoporous acid-free silica xerogels exhibiting a proton conductivity of 2.0 × 10 -2 S cm -1 at 80 °C and 81% RH is reported for the first time. The proton conductivity values, lower cost and higher hydrophilicity of mesoporous silica xerogels make them potential substitutes for Nafion membranes in proton exchange membranes fuel cells (PEMFCs).

  19. The Synthesis of Cadmium Doped Mesoporous TiO2

    SciTech Connect

    Li, Xiaohong S.; Fryxell, Glen E.; Engelhard, Mark H.; Wang, Chong M.

    2007-06-01

    Cd doped mesoporous titanium oxide was prepared using non-ionic surfactants and easily handled titanium precursors. The Cd doping was found to be able to significantly inhibit the growth of anatase crystal size, stabilize the mesoporous structure, and retard the densification of nanoporous TiO2 at elevated temperatures.

  20. Mesoporous silicates: Materials science and biological applications

    NASA Astrophysics Data System (ADS)

    Roggers, Robert Anthony

    This thesis dissertation presents the collective research into the advancement of mesoporous silicate particles as biointerface devices, the development of new materials and the application of these particles as solid supports for heterogeneous catalysis. Mesoporous silica has been utilized in the aforementioned applications due to several reasons; the first being the ability to achieve high surface areas (500 - 1000 m2 g-1) with controlled pore sizes and particle morphology. Another reason for their popularity is their robustness in applications of heterogeneous catalysis and the ability to functionalize the surface with a wide variety of organic functional groups. In the field of biointerface devices, mesoporous silica nanoparticles represent a class of materials that exhibit high biocompatibility. In addition, the ability to functionalize the surfaces (outer surface and pore interiors) allows the particles to be targeted to specific cell types as well as the ability to release many different therapeutic molecules under specific stimuli. A unique particle coating consisting of a chemically cleavable lipid bilayer that allows for the encapsulation of a fluorescent molecule and increases the biocompatibility of the particle has been developed. The lipid bilayer coated mesoporous silica nanoparticle (LB-MSN) was characterized using X-ray diffraction, transmission electron microscopy and nitrogen `sorption isotherms. The finished LB-MSN was then incubated with mammalian cells in order to prove their biocompatibility. Confocal micrographs demonstrate the endocytosis of the particles into the cells. In addition the micrographs also show that the LB-MSNs are separate from the endosomal compartments, however due to the lipophilic nature of the dye used to label the endosome there is some debate regarding this conclusion. The lipid bilayer coating was then applied to a large pore MSN (l-MSN) which had been previously shown to cause lysis of red blood cells (RBCs) at low

  1. Novel mesoporous P-doped graphitic carbon nitride nanosheets coupled with ZnIn2S4 nanosheets as efficient visible light driven heterostructures with remarkably enhanced photo-reduction activity.

    PubMed

    Chen, Wei; Liu, Tian-Yu; Huang, Ting; Liu, Xiao-Heng; Yang, Xu-Jie

    2016-02-14

    In this report, we rationally designed and fabricated P-C3N4/ZnIn2S4 nanocomposites by in situ immobilizing ZnIn2S4 nanosheets onto the surface of mesoporous P-doped graphite carbon nitrogen (P-C3N4) nanosheets in a mixed solvothermal environment; their application to the photoreduction of 4-nitroaniline was used to estimate the photocatalytic performance. Different to the template route, here the mesoporous P-C3N4 nanosheets were prepared with a template-free strategy. The as-fabricated P-C3N4/ZnIn2S4 nanocomposites were systematically characterized by analyzing the phase structure, chemical components, electronic and optical properties and separation of charge carrier pairs. More importantly, these P-C3N4/ZnIn2S4 heterostructures have been proven to be highly efficient visible light responsive photocatalysts for photo-reduction, and meanwhile exhibit excellent photo-stability during recycling runs. The sufficient evidence reveals that the significantly improved photocatalytic performance is mainly attributed to the more efficient charge carrier separation based on the construction of a close heterogeneous interface. This work may provide new insights into the utilization of P-C3N4/ZnIn2S4 nanocomposites as visible light driven photocatalysts for comprehensive organic transformations in the field of fine chemical engineering. PMID:26815611

  2. Multifunctional nanocomposite materials. Progress report

    SciTech Connect

    Roy, R.; Komarneni, S.

    1991-11-01

    Objective is to examine the low temperature nanocomposite route in the synthesis of multifunctional materials using two-dimensional clays as hosts. After about 8 months, a significant advance was made in the design and synthesis of novel nanocomposite materials, which are nanometal intercalated clays prepared by a low temperature route. A layered V{sub 2}O{sub 5} gel has been made hydrothermally and its cation exchange properties measured. Several pillared clays have also been synthesized and characterized.

  3. Ordered three- and five-ply nanocomposites from ABC block terpolymer microphase separation with niobia and aluminosilicate sols

    PubMed Central

    Stefik, Morgan; Mahajan, Surbhi; Sai, Hiroaki; Epps, Thomas H.; Bates, Frank S.; Gruner, Sol M; DiSalvo, Francis J.; Wiesner, Ulrich

    2009-01-01

    We report the first use of a non-frustrated block terpolymer for the synthesis of highly ordered oxide nanocomposites containing multiple plies. The morphological behavior of 15 ISO-oxide nanocomposites was investigated spanning a large range of compositions along the ƒI=ƒS isopleth using aluminosilicate and niobia sols. Morphologies were determined by TEM and SAXS measurements. Four morphologies were identified, including core-shell hexagonal, core-shell double gyroid, three-domain lamellae, and core-shell inverse-hexagonal, in order of increasing O+oxide vol fraction. All of the resulting nanocomposites had three- or five-ply morphologies containing domains that were continuous in one, two, or three dimensions. The five-ply core-shell double gyroid phase was only found to be stable when the O+oxide domain was a minority. Removal of the polymer enabled simple and direct synthesis of mesoporous oxide materials while retaining the ordered network structure. We believe that advances in the synthesis of multi-ply nanocomposites will lead to advanced materials and devices containing multiple plies of functional materials. PMID:20209023

  4. [Study on absorbing volatile oil with mesoporous carbon].

    PubMed

    Yan, Hong-mei; Jia, Xiao-bin; Zhang, Zhen-hai; Sun, E; Yang Nan

    2014-11-01

    Clove oil and turmeric oil were absorbed by mesoporous carbon. The absorption ratio of mesoporous carbon to volatile oil was optimized with the eugenol yield and curcumol yield as criteria Curing powder was characterized by scanning electron microscopy (SEM) and differential scanning calorietry (DSC). The effects of mesoporous carbon on dissolution in vitro and thermal stability of active components were studied. They reached high adsorption rate when the absorption ratio of mesoporous carbon to volatile oil was 1:1. When volatile oil was absorbed, dissolution rate of active components had a little improvement and their thermal stability improved after volatile oil was absorbed by the loss rate decreasing more than 50%. Absorbing herbal volatile oil with mesoporous carbon deserves further studying. PMID:25850263

  5. Biodegradation-tunable mesoporous silica nanorods for controlled drug delivery.

    PubMed

    Park, Sung Bum; Joo, Young-Ho; Kim, Hyunryung; Ryu, WonHyoung; Park, Yong-il

    2015-05-01

    Mesoporous silica in the forms of micro- or nanoparticles showed great potentials in the field of controlled drug delivery. However, for precision control of drug release from mesoporous silica-based delivery systems, it is critical to control the rate of biodegradation. Thus, in this study, we demonstrate a simple and robust method to fabricate "biodegradation-tunable" mesoporous silica nanorods based on capillary wetting of anodic aluminum oxide (AAO) template with an aqueous alkoxide precursor solution. The porosity and nanostructure of silica nanorods were conveniently controlled by adjusting the water/alkoxide molar ratio of precursor solutions, heat-treatment temperature, and Na addition. The porosity and biodegradation kinetics of the fabricated mesoporous nanorods were analyzed using N2 adsorption/desorption isotherm, TGA, DTA, and XRD. Finally, the performance of the mesoporous silica nanorods as drug delivery carrier was demonstrated with initial burst and subsequent "zero-order" release of anti-cancer drug, doxorubicin. PMID:25746247

  6. Synthesis and catalytic applications of combined zeolitic/mesoporous materials

    PubMed Central

    Vernimmen, Jarian; Cool, Pegie

    2011-01-01

    Summary In the last decade, research concerning nanoporous siliceous materials has been focused on mesoporous materials with intrinsic zeolitic features. These materials are thought to be superior, because they are able to combine (i) the enhanced diffusion and accessibility for larger molecules and viscous fluids typical of mesoporous materials with (ii) the remarkable stability, catalytic activity and selectivity of zeolites. This review gives an overview of the state of the art concerning combined zeolitic/mesoporous materials. Focus is put on the synthesis and the applications of the combined zeolitic/mesoporous materials. The different synthesis approaches and formation mechanisms leading to these materials are comprehensively discussed and compared. Moreover, Ti-containing nanoporous materials as redox catalysts are discussed to illustrate a potential implementation of combined zeolitic/mesoporous materials. PMID:22259762

  7. Characterization and photocatalytic activity of (ZnO–CuO)/SBA-15 nanocomposites synthesized by two-solvent method

    SciTech Connect

    Dai, Peng; Zhang, Lili; Zhang, Gongtuo; Li, Guang; Sun, Zhaoqi; Liu, Xiansong; Wu, Mingzai

    2014-08-15

    Schematic between charge genenration and transfer for methylene orange degradation simulated by light. - Highlights: • Two-solvent method is used to prepare ZnO–CuO particles embedded in porous SBA-15. • The absorption edge of (ZnO–CuO)/SBA-15 composite is in the visible light regime. • The absorption intensity of the composite in visible light regime is enhanced. • The (ZnO–CuO)/SBA-15 composite has higher photocatalytic ability than Degussa P-25. - Abstract: Two-solvent method was employed to prepare ZnO–CuO nanoparticles embedded in mesoporous silica SBA-15 ((ZnO–CuO)/SBA-15). The as-obtained (ZnO–CuO)/SBA-15 nanocomposites were characterized by X-ray diffraction, transmission electron microscope, X-ray photoelectron spectroscopy, N{sub 2} adsorption porosimetry, and diffusive reflective UV–vis spectroscopy. The photocatalytic activity of (ZnO–CuO)/SBA-15 nanocomposites toward methylene orange was investigated under simulated solar light irradiation, and the measurement results indicated that (ZnO–CuO)/SBA-15 nanocomposites exhibit higher photodegradation activity toward methylene orange than commercial TiO{sub 2} P-25. The photocatalytic activity of (ZnO–CuO)/SBA-15 nanocomposites were found to be dependent on both the adsorption ability of the nanocomposites and the loading dosage of ZnO–CuO nanoparticles in SBA-15. The optimal loading dosage of ZnO–CuO nanoparticles was determined. Too high or too low loading will lower the photodegradation ability of (ZnO–CuO)/SBA-15 nanocomposites.

  8. Microwave-induced synthesis of highly dispersed gold nanoparticles within the pore channels of mesoporous silica

    SciTech Connect

    Gu Jinlou; Fan Wei; Shimojima, Atsushi; Okubo, Tatsuya

    2008-04-15

    Highly dispersed gold nanoparticles have been incorporated into the pore channels of SBA-15 mesoporous silica through a newly developed strategy assisted by microwave radiation (MR). The sizes of gold are effectively controlled attributed to the rapid and homogeneous nucleation, simultaneous propagation and termination of gold precursor by MR. Diol moieties with high dielectric and dielectric loss constants, and hence a high microwave activation, were firstly introduced to the pore channels of SBA-15 by a simple addition reaction between amino group and glycidiol and subsequently served as the reduction centers for gold nanoparticles. Extraction of the entrapped gold from the nanocomposite resulted in milligram quantities of gold nanoparticles with low dispersity. The successful assembly process of diol groups and formation of gold nanoparticles were monitored and tracked by solid-state NMR and UV-vis measurements. Characterization by small angle X-ray diffraction (XRD) and transmission electron microscopy (TEM) indicated that the incorporation of gold nanoparticles would not breakup the structural integrity and long-range periodicity of SBA-15. The gold nanoparticles had a narrow size distribution with diameters in the size range of 5-10 nm through TEM observation. The average particles size is 7.9 nm via calculation by the Scherrer formula and TEM measurements. Nitrogen adsorption and desorption isotherms gave further evidence that the employed method was efficient and gold nanoparticles were successfully incorporated into the pore channels of SBA-15. - Graphical abstract: A facile and novel strategy has been developed to incorporate gold nanoparticles into the pore channels of mesoporous SBA-15 assisted by microwave radiation (MR) with mild reaction condition and rapid reaction speed. Due to the rapid and homogeneous nucleation, simultaneous propagation and termination by MR, the size of gold nanoparticles are effectively controlled.

  9. Magnetoelectric polymer nanocomposite for flexible electronics

    SciTech Connect

    Alnassar, M. Alfadhel, A.; Ivanov, Yu. P.; Kosel, J.

    2015-05-07

    This paper reports the fabrication and characterization of a new type of magnetoelectric polymer nanocomposite that exhibits excellent ferromagnetism and ferroelectricity simultaneously at room temperature. The multiferroic nanocomposite consists of high aspect ratio ferromagnetic iron nanowires embedded inside a ferroelectric co-polymer poly(vinylindene fluoride-trifluoroethylene), P(VDF-TrFE). The nanocomposite has been fabricated via a simple low temperature spin coating technique. Structural, ferromagnetic, ferroelectric, and magnetoelectric properties of the developed nanocomposite have been characterized. The nanocomposite films showed isotropic magnetic properties due to the random orientation of the iron nanowires inside the film. In addition, the embedded nanowires did not hinder the ferroelectric phase development of the nanocomposite. The developed nanocomposite showed a high magnetoelectric coupling response of 156 mV/cmOe measured at 3.1 kOe DC bias field. This value is among the highest reported magnetoelectric coupling in two phase particulate polymer nanocomposites.

  10. Effect of Nanofiller Characteristics on Nanocomposite Properties

    NASA Technical Reports Server (NTRS)

    Working, Dennis C.; Lillehei, Peter T.; Lowther, Sharon E.; Siochi, Emilie J.; Kim, Jae-Woo; Sauti, Godfrey; Wise, Kristopher E.; Park, Cheol

    2016-01-01

    This report surveys the effect of nanofiller characteristics on nanocomposites fabricated with two polyimide matrices. Mechanical and electrical properties were determined. Microscopy results showed that matrix chemistry, nanofiller characteristics and processing conditions had significant impact on nanocomposite quality.

  11. High-efficient mercury removal from environmental water samples using di-thio grafted on magnetic mesoporous silica nanoparticles.

    PubMed

    Mehdinia, Ali; Akbari, Maryam; Baradaran Kayyal, Tohid; Azad, Mohammad

    2015-02-01

    In this work, magnetic di-thio functionalized mesoporous silica nanoparticles (DT-MCM-41) were prepared by grafting dithiocarbamate groups within the channels of magnetic mesoporous silica nanocomposites. The functionalized nanoparticles exhibited proper magnetic behavior. They were easily separated from the aqueous solution by applying an external magnetic field. The results indicated that the functionalized nanoparticles had a potential for high-efficient removal of Hg(2+) in environmental samples. The maximum adsorption capacity of the sorbent was 538.9 mg g(-1), and it took about 10 min to achieve the equilibrium adsorption. The resulted adsorption capacity was higher than similar works for adsorption of mercury. It can be due to the presence of di-thio and amine active groups in the structure of sorbent. The special properties of MCM-41 like large surface area and high porosity also provided a facile accessibility of the mercury ions into the ligand sites. The complete removal of mercury ions was attained with dithiocarbamate groups in a wide range of mercury concentrations. The recovery studies were also applied for the river water, seawater, and wastewater samples, and the values were over of 97 %. PMID:25172459

  12. In-situ reduction of monodisperse nanosilver on hierarchical wrinkled mesoporous silica with radial pore channels and its antibacterial performance.

    PubMed

    Wan, Xuejuan; Zhuang, Lulu; She, Boxi; Deng, Yuanming; Chen, Dazhu; Tang, Jiaoning

    2016-08-01

    Monodisperse silver nanoparticles (Ag NPs) were facilely loaded on the inner and outer surface of hierarchical wrinkled mesoporous silica (WMSs) via an in situ chemical reduction, and the antibacterial capacity of the obtained nanocomposite was investigated in detail. Typical sulfydryl-functionalized wrinkled mesoporous silica nanoparticle with radical pore channels was firstly prepared through sol-gel technique with cetyltrimethylammonium bromide (CTAB) as the templating surfactant. After sulfonation of the as-prepared WMSs, Ag(+) ions were then densely locked up on the inner and outer surface of WMSs via electrostatic interactions. Well distributed Ag NPs (ca. 3-5nm) on WMSs without any agglomeration were finally obtained via a simple in situ reduction reaction with sodium borohydride. Minimal inhibitory concentration (MIC) and minimal bactericidal concentration (MBC) test indicated that the obtained products can achieve durable and much better antibacterial performance both against Gram-negative bacterium Escherichia coli (E. coli) and Gram-positive bacterium Staphylococcus aureus (S. aureus) comparing to pure colloidal silver nanoparticles, which rendered them as favorable candidate for the development of effective antibacterial agents. PMID:27157758

  13. DNA-Hybrid-Gated Photothermal Mesoporous Silica Nanoparticles for NIR-Responsive and Aptamer-Targeted Drug Delivery.

    PubMed

    Zhang, Yuanxin; Hou, Zhiyao; Ge, Yakun; Deng, Kerong; Liu, Bei; Li, Xuejiao; Li, Quanshun; Cheng, Ziyong; Ma, Ping'an; Li, Chunxia; Lin, Jun

    2015-09-23

    Near-infrared light is an attractive stimulus due to its noninvasive and deep tissue penetration. Particularly, NIR light is utilized for cancer thermotherapy and on-demand release of drugs by the disruption of the delivery carriers. Here we have prepared a novel NIR-responsive DNA-hybrid-gated nanocarrier based on mesoporous silica-coated Cu1.8S nanoparticles. Cu1.8S nanoparticles, possessing high photothermal conversion efficiency under a 980 nm laser, were chosen as photothermal agents. The mesoporous silica structure could be used for drug storage/delivery and modified with aptamer-modified GC-rich DNA-helix as gatekeepers, drug vectors, and targeting ligand. Simultaneously, the as-produced photothermal effect caused denaturation of DNA double strands, which triggered the drug release of the DNA-helix-loaded hydrophilic drug doxorubicin and mesopore-loaded hydrophobic drug curcumin, resulting in a synergistic therapeutic effect. The Cu1.8S@mSiO2 nanocomposites endocytosed by cancer cells through the aptamer-mediated mode are able to generate rational release of doxorubicin/curcumin under NIR irradiation, strongly enhancing the synergistic growth-inhibitory effect of curcumin against doxorubicin in MCF-7 cells, which is associated with a strong mitochondrial-mediated cell apoptosis progression. The underlying mechanism of apoptosis showed a strong synergistic inhibitory effect both on the expression of Bcl-2, Bcl-xL, Mcl-1, and upregulated caspase 3/9 activity and on the expression level of Bak and Bax. Therefore, Cu1.8S@mSiO2 with efficient synergistic therapeutic efficiency is a potential multifunctional cancer therapy nanoplatform. PMID:26325285

  14. High psedocapacitance of MnO2 nanoparticles in graphitic disordered mesoporous carbon at high scan rates

    SciTech Connect

    Dai, Sheng; Patel, Mehul; Wang, Xiqing; Slanac, Daniel A; Ferrer, Domingo; Johnston, Keith; Stevenson, Keith J

    2012-01-01

    Nanocomposites composed of MnO{sub 2} and graphitic disordered mesoporous carbon (MnO{sub 2}/C) were synthesized for high total specific capacitance and redox pseudocapacitance (C{sub MnO{sub 2}}) at high scan rates up to 200 mV s{sup -1}. High resolution transmission electron microscopy (HRTEM) with energy dispersive X-ray spectroscopy (EDX) demonstrated that MnO{sub 2} nanodomains were highly dispersed throughout the mesoporous carbon structure. According to HRTEM and X-ray diffraction (XRD), the MnO{sub 2} domains are shown to be primarily amorphous and less than 5 nm in size. For these composites in aqueous 1 M Na{sub 2}SO{sub 4} electrolyte, C{sub MnO{sub 2}} reached 500 F/g{sub MnO{sub 2}} at 2 mV s{sup -1} for 8.8 wt% MnO{sub 2}. A capacitance fade of only 20% over a 100-fold change in scan rate was observed for a high loading of 35 wt% MnO{sub 2} with a C{sub MnO{sub 2}} of 310 F/g{sub MnO{sub 2}} at the highest scan rate of 200 mV s{sup -1}. The high electronic conductivity of the graphitic 3D disordered mesoporous carbon support in conjunction with the thin MnO{sub 2} nanodomains facilitate rapid electron and ion transport offering the potential of improved high power density energy storage pseudocapacitors.

  15. High pseudocapacitance of MnO2 nanoparticles in graphitic disordered mesoporous carbon at high scan rates

    SciTech Connect

    Dai, Sheng; Patel, Mehul; Wang, Xiqing; Slanac, Daniel A; Ferrer, Domingo; Johnston, Keith

    2012-01-01

    Nanocomposites composed of MnO{sub 2} and graphitic disordered mesoporous carbon (MnO{sub 2}/C) were synthesized for high total specific capacitance and redox pseudocapacitance (C{sub MnO{sub 2}}) at high scan rates up to 200 mV s{sup -1}. High resolution transmission electron microscopy (HRTEM) with energy dispersive X-ray spectroscopy (EDX) demonstrated that MnO{sub 2} nanodomains were highly dispersed throughout the mesoporous carbon structure. According to HRTEM and X-ray diffraction (XRD), the MnO{sub 2} domains are shown to be primarily amorphous and less than 5 nm in size. For these composites in aqueous 1 M Na{sub 2}SO{sub 4} electrolyte, C{sub MnO{sub 2}} reached 500 F/g{sub MnO{sub 2}} at 2 mV s{sup -1} for 8.8 wt% MnO{sub 2}. A capacitance fade of only 20% over a 100-fold change in scan rate was observed for a high loading of 35 wt% MnO{sub 2} with a C{sub MnO{sub 2}} of 310 F/g{sub MnO{sub 2}} at the highest scan rate of 200 mV s{sup -1}. The high electronic conductivity of the graphitic 3D disordered mesoporous carbon support in conjunction with the thin MnO{sub 2} nanodomains facilitate rapid electron and ion transport offering the potential of improved high power density energy storage pseudocapacitors.

  16. Enhancing the photocatalytic activity of bulk g-C₃N₄ by introducing mesoporous structure and hybridizing with graphene.

    PubMed

    Li, Yuhan; Sun, Yanjuan; Dong, Fan; Ho, Wing-Kei

    2014-12-15

    Bulk graphitic carbon nitride (CN) suffers from small surface area and high recombination of charge carriers, which result in low photocatalytic activity. To enhance the activity of g-C3N4, the surface area should be enlarged and charge carrier separation should be promoted. In this work, a combined strategy was employed to dramatically enhance the activity of bulk g-C3N4 by simultaneously introducing mesoporous structure and hybridizing with graphene/graphene oxide. The mesoporous g-C3N4/graphene (MCN-G) and mesoporous g-C3N4/graphene oxide (MCN-GO) nanocomposites with enhanced photocatalytic activity (NO removal ratio of 64.9% and 60.7%) were fabricated via a facile sonochemical method. The visible light-harvesting ability of MCN-G and MCN-GO hybrids was enhanced and the conduction band was negatively shifted when 1.0 wt% graphene/graphene oxide was incorporated into the matrix of MCN. As electronic conductive channels, the G/GO sheets could efficiently facilitate the separation of chare carriers. MCN-G and MCN-GO exhibited drastically enhanced visible light photocatalytic activity toward NO removal. The NO removal ratio increased from 16.8% for CN to 64.9% for MCN-G and 60.7% for MCN-GO. This enhanced photocatalytic activity could be attributed to the increased surface area and pore volume, improved visible light utilization, enhanced reduction power of electrons, and promoted separation of charge carriers. This work demonstrates that a combined strategy is extremely effective for the development of active photocatalysts in environmental and energetic applications. PMID:25265582

  17. Contribution of mesopores in MgO-templated mesoporous carbons to capacitance in non-aqueous electrolytes

    NASA Astrophysics Data System (ADS)

    Kado, Yuya; Soneda, Yasushi; Yoshizawa, Noriko

    2015-02-01

    MgO-templated mesoporous carbons were fabricated by annealing trimagnesium dicitrate nonahydrate at various temperatures from 700 to 1000 °C with subsequent acid leaching of MgO. The obtained carbons contained a large amount of mesopores. Performances of electric double-layer capacitors using these carbons were examined for propylene carbonate electrolyte containing 1 M tetraethylammonium tetrafluoroborate. The mesoporous carbons synthesized at higher temperatures showed better rate capabilities. AC impedance measurements indicated that high-temperature annealing of the carbon precursors and the presence of mesopores were important for high rate performance. In addition, the contribution of mesopores to capacitance was more significant at higher current densities of 30 A g-1.

  18. Characterisations of collagen-silver-hydroxyapatite nanocomposites

    NASA Astrophysics Data System (ADS)

    Ciobanu, C. S.; Popa, C. L.; Petre, C. C.; Jiga, G.; Trusca, R.; Predoi, D.

    2016-05-01

    The XRD analysis were performed to confirm the formation of hydroxyapatite structure in collagen-silver-hydroxyapatite nanocomposites. The molecular interaction in collagen-hydroxyapatite nanocomposites was highlighted by Fourier transform infrared spectroscopy (FTIR) analysis. The SEM showed a nanostructure of collagen-silverhydroxyapatite nanocomposites composed of nano needle-like particles in a veil with collagen texture. The presence of vibrational groups characteristics to the hydroxyapatite structure in collagen-silver-hydroxyapatite (AgHApColl) nanocomposites was investigated by FTIR.

  19. How Nano Are Nanocomposites

    SciTech Connect

    Schaefer, Dale W.; Justice, Ryan S.

    2010-10-22

    Composite materials loaded with nanometer-sized reinforcing fillers are widely believed to have the potential to push polymer mechanical properties to extreme values. Realization of anticipated properties, however, has proven elusive. The analysis presented here traces this shortfall to the large-scale morphology of the filler as determined by small-angle X-ray scattering, light scattering, and electron imaging. We examine elastomeric, thermoplastic, and thermoset composites loaded with a variety of nanoscale reinforcing fillers such as precipitated silica, carbon nanotubes (single and multiwalled), and layered silicates. The conclusion is that large-scale disorder is ubiquitous in nanocomposites regardless of the level of dispersion, leading to substantial reduction of mechanical properties (modulus) compared to predictions based on idealized filler morphology.

  20. Hierarchical organization and molecular diffusion in gold nanorod/silica supercrystal nanocomposites

    NASA Astrophysics Data System (ADS)

    Hamon, Cyrille; Sanz-Ortiz, Marta N.; Modin, Evgeny; Hill, Eric H.; Scarabelli, Leonardo; Chuvilin, Andrey; Liz-Marzán, Luis M.

    2016-04-01

    Hierarchical organization of gold nanorods was previously obtained on a substrate, allowing precise control over the morphology of the assemblies and macroscale spatial arrangement. Herein, a thorough description of these gold nanorod assemblies and their orientation within supercrystals is presented together with a sol-gel technique to protect the supercrystals with mesoporous silica films. The internal organization of the nanorods in the supercrystals was characterized by combining focused ion beam ablation and scanning electron microscopy. A mesoporous silica layer is grown both over the supercrystals and between the individual lamellae of gold nanorods inside the structure. This not only prevented the detachment of the supercrystal from the substrate in water, but also allowed small molecule analytes to infiltrate the structure. These nanocomposite substrates show superior Raman enhancement in comparison with gold supercrystals without silica owing to improved accessibility of the plasmonic hot spots to analytes. The patterned supercrystal arrays with enhanced optical and mechanical properties obtained in this work show potential for the practical implementation of nanostructured devices in spatially resolved ultradetection of biomarkers and other analytes.Hierarchical organization of gold nanorods was previously obtained on a substrate, allowing precise control over the morphology of the assemblies and macroscale spatial arrangement. Herein, a thorough description of these gold nanorod assemblies and their orientation within supercrystals is presented together with a sol-gel technique to protect the supercrystals with mesoporous silica films. The internal organization of the nanorods in the supercrystals was characterized by combining focused ion beam ablation and scanning electron microscopy. A mesoporous silica layer is grown both over the supercrystals and between the individual lamellae of gold nanorods inside the structure. This not only prevented the

  1. Nanocomposites of POC and quantum dots

    NASA Astrophysics Data System (ADS)

    Borriello, C.; Concilio, S.; Minarini, C.; Iannelli, P.; Di Luccio, T.

    2012-07-01

    New luminescent polymer nanocomposites were synthesized combining carbazole/oxadiazole copolymer (POC) and CdSe/ZnS quantum dots (QDs) surface passivated by ionic liquids. Ionic liquid ligands improve the photostability of QDs and their compatibility with polymer allowing the deposition of homogeneous nanocomposites films. The nanocomposites were characterized by UV and photoluminescence spectroscopy.

  2. The development of chiral nematic mesoporous materials.

    PubMed

    Kelly, Joel A; Giese, Michael; Shopsowitz, Kevin E; Hamad, Wadood Y; MacLachlan, Mark J

    2014-04-15

    Cellulose nanocrystals (CNCs) are obtained from the sulfuric acid-catalyzed hydrolysis of bulk cellulose. The nanocrystals have diameters of ~5-15 nm and lengths of ~100-300 nm (depending on the cellulose source and hydrolysis conditions). This lightweight material has mostly been investigated to reinforce composites and polymers because it has remarkable strength that rivals carbon nanotubes. But CNCs have an additional, less explored property: they organize into a chiral nematic (historically referred to as cholesteric) liquid crystal in water. When dried into a thin solid film, the CNCs retain the helicoidal chiral nematic order and assemble into a layered structure where the CNCs have aligned orientation within each layer, and their orientation rotates through the stack with a characteristic pitch (repeating distance). The cholesteric ordering can act as a 1-D photonic structure, selectively reflecting circularly polarized light that has a wavelength nearly matching the pitch. During CNC self-assembly, it is possible to add sol-gel precursors, such as Si(OMe)4, that undergo hydrolysis and condensation as the solvent evaporates, leading to a chiral nematic silica/CNC composite material. Calcination of the material in air destroys the cellulose template, leaving a high surface area mesoporous silica film that has pore diameters of ~3-10 nm. Importantly, the silica is brilliantly iridescent because the pores in its interior replicate the chiral nematic structure. These films may be useful as optical filters, reflectors, and membranes. In this Account, we describe our recent research into mesoporous films with chiral nematic order. Taking advantage of the chiral nematic order and nanoscale of the CNC templates, new functional materials can be prepared. For example, heating the silica/CNC composites under an inert atmosphere followed by removal of the silica leaves highly ordered, mesoporous carbon films that can be used as supercapacitor electrodes. The composition

  3. A multifunctional biphasic suspension of mesoporous silica encapsulated with YVO4:Eu3+ and Fe3O4 nanoparticles: synergistic effect towards cancer therapy and imaging

    NASA Astrophysics Data System (ADS)

    Shanta Singh, N.; Kulkarni, Hrishikesh; Pradhan, Lina; Bahadur, D.

    2013-02-01

    Polyol mediated synthesized luminescent YVO4:Eu3+ nanoparticles (NPs) have been encapsulated in mesoporous silica nanoparticles (MSNs) using the sol-gel process. X-ray diffraction and Fourier transform infrared spectroscopy along with transmission electron microscopy confirm the encapsulation of the YVO4:Eu3+ NPs in the SiO2 matrix. N2 adsorption/desorption analysis confirms the mesoporous nature of the MSNs and YVO4:Eu3+-MSNs. No significant quenching of the YVO4:Eu3+ luminescence is observed for YVO4:Eu3+-MSNs. This nanocomposite has been tested as a potential drug carrier. Efficient loading of doxorubicin hydrochloride (DOX), a typical anticancer drug, is observed which reaches up to 93% in 8 mg ml-1 of YVO4:Eu3+-MSNs. pH sensitive release of DOX is observed, with 54% release for pH 4.3 and 31% in a physiological environment (pH 7.4). Both MSNs and YVO4:Eu3+-MSNs nanocomposites do not show accountable toxicity to two cell lines, i.e. HeLa and MCF-7. However, as desired, toxicity is observed when cells are incubated with DOX loaded YVO4:Eu3+-MSNs. Laser scanning confocal microscopy images confirm the uptake of the nanocomposite in both cell lines. The morphology of the cells (MCF-7) changes after incubation with DOX loaded YVO4:Eu3+-MSNs, indicating an interaction of DOX with the cells. More cytotoxicity to both cell lines with ˜90% killing is observed due to the synergistic effect of magnetic fluid hyperthermia and chemotherapy using a biphasic suspension of superparamagnetic iron oxide magnetic nanoparticles and DOX loaded YVO4:Eu3+-MSNs. In addition, an AC magnetic field triggers an enhanced drug release.

  4. A multifunctional biphasic suspension of mesoporous silica encapsulated with YVO4:Eu3+ and Fe3O4 nanoparticles: synergistic effect towards cancer therapy and imaging.

    PubMed

    Shanta Singh, N; Kulkarni, Hrishikesh; Pradhan, Lina; Bahadur, D

    2013-02-15

    Polyol mediated synthesized luminescent YVO(4):Eu(3+) nanoparticles (NPs) have been encapsulated in mesoporous silica nanoparticles (MSNs) using the sol-gel process. X-ray diffraction and Fourier transform infrared spectroscopy along with transmission electron microscopy confirm the encapsulation of the YVO(4):Eu(3+) NPs in the SiO(2) matrix. N(2) adsorption/desorption analysis confirms the mesoporous nature of the MSNs and YVO(4):Eu(3+)-MSNs. No significant quenching of the YVO(4):Eu(3+) luminescence is observed for YVO(4):Eu(3+)-MSNs. This nanocomposite has been tested as a potential drug carrier. Efficient loading of doxorubicin hydrochloride (DOX), a typical anticancer drug, is observed which reaches up to 93% in 8 mg ml(-1) of YVO(4):Eu(3+)-MSNs. pH sensitive release of DOX is observed, with 54% release for pH 4.3 and 31% in a physiological environment (pH 7.4). Both MSNs and YVO(4):Eu(3+)-MSNs nanocomposites do not show accountable toxicity to two cell lines, i.e. HeLa and MCF-7. However, as desired, toxicity is observed when cells are incubated with DOX loaded YVO(4):Eu(3+)-MSNs. Laser scanning confocal microscopy images confirm the uptake of the nanocomposite in both cell lines. The morphology of the cells (MCF-7) changes after incubation with DOX loaded YVO(4):Eu(3+)-MSNs, indicating an interaction of DOX with the cells. More cytotoxicity to both cell lines with ∼90% killing is observed due to the synergistic effect of magnetic fluid hyperthermia and chemotherapy using a biphasic suspension of superparamagnetic iron oxide magnetic nanoparticles and DOX loaded YVO(4):Eu(3+)-MSNs. In addition, an AC magnetic field triggers an enhanced drug release. PMID:23324398

  5. Modified Mesoporous Silica for Efficient Siloxane Capture.

    PubMed

    Jafari, Tahereh; Jiang, Ting; Zhong, Wei; Khakpash, Nasser; Deljoo, Bahareh; Aindow, Mark; Singh, Prabhakar; Suib, Steven L

    2016-03-15

    In this study, octamethylcyclotetrasiloxane (D4) was removed by using a novel modified solid adsorbent of mesoporous silica. The adsorbent was synthesized using inverse micelles with some modifications in the synthesis process (temperature of gelation) and in the post treatment conditions (calcination temperature and heating rate) with a concomitant improvement of D4 uptake. This is the first report on regulating the textural properties of the mesoporous silica material UCT-14 to develop an active silica adsorbent. These adjustments resulted in an increase of the silica surface area from 391 to 798 m(2)·g(-1), which leads to a high capacity (686 mg·g(-1)) of D4-capture for the silica synthesized at 80 °C, calcined at 450 °C with the heating rate of 100 °C·min(-1) (Si-Syn80). This adsorbent showed comparable adsorption performance with the widely used commercial silica gel under dry and humid condition. Recyclability tests on the commercial silica gel and mesoporous silica synthesized at 120 °C and calcined at 450 °C with a heating rate of 100 °C·min(-1) (called Si-Syn120 or Si-450 or Si-100 °C·min(-1)) indicated that the Si-Syn120 (capacity drop 10%) is more efficient than silica gel (capacity drop 15%) after three cycles. Although, the presence of moisture (25%) in the nitrogen gas stream led to capacity reduction in both Si-Syn120 and commercial silica gel, the modified UCT-14 shows slightly better resistance to humid condition. PMID:26890152

  6. Fluorescence properties of dye doped mesoporous silica

    NASA Astrophysics Data System (ADS)

    Carbonaro, Carlo M.; Corpino, Riccardo; Ricci, Pier Carlo; Chiriu, Daniele; Cannas, Carla

    2014-10-01

    In this paper we present a review of the main results we obtained studying the emission properties of organic-inorganic hybrids obtained combining mesoporous silica and Xantene dyes, in particular the standard referenc Rhodamine 6G. The purpose of the review is to show the possibility to efficiently "dope" the transparent inorganic porous matrix to obtain promising systems for photonic and biomedical applications. The strategies to solve the concentration effect and the leaching phenomenon are discussed within the framework of the single exciton theory.

  7. Mesoporous silica-titania composed materials.

    PubMed

    Messina, Paula V; Morini, Marcela A; Sierra, María B; Schulz, Pablo C

    2006-08-01

    Titania mesosized particles were obtained by TiCl4 hydrolysis in Aerosol OT/water/n-hexane microemulsion. These particles were incorporated in surfactant templated silica mesoporous materials of MCM-41 and MCM-50 structures. Results depended on the surfactant: hexadecyltrimethylammonium bromide templated materials retained the honeycomb structure with small modifications in their characteristics. The dodecyltrimethylammonium bromide templated material changed from honeycomb to lamellar structure when the titania particles were included, with dramatic changes in the structure characteristics. The didodecyldimethylammonium bromide templated lamellar structure was retained after TIO2 inclusion, with a slight increase in the specific area, pore diameter and pore walls thickness. PMID:16600274

  8. Fluorescence properties of dye doped mesoporous silica

    SciTech Connect

    Carbonaro, Carlo M. Corpino, Riccardo Ricci, Pier Carlo Chiriu, Daniele; Cannas, Carla

    2014-10-21

    In this paper we present a review of the main results we obtained studying the emission properties of organic-inorganic hybrids obtained combining mesoporous silica and Xantene dyes, in particular the standard reference Rhodamine 6G. The purpose of the review is to show the possibility to efficiently 'dope' the transparent inorganic porous matrix to obtain promising systems for photonic and biomedical applications. The strategies to solve the concentration effect and the leaching phenomenon are discussed within the framework of the single exciton theory.

  9. Advanced hybrid supercapacitor based on a mesoporous niobium pentoxide/carbon as high-performance anode.

    PubMed

    Lim, Eunho; Kim, Haegyeom; Jo, Changshin; Chun, Jinyoung; Ku, Kyojin; Kim, Seongseop; Lee, Hyung Ik; Nam, In-Sik; Yoon, Songhun; Kang, Kisuk; Lee, Jinwoo

    2014-09-23

    Recently, hybrid supercapacitors (HSCs), which combine the use of battery and supercapacitor, have been extensively studied in order to satisfy increasing demands for large energy density and high power capability in energy-storage devices. For this purpose, the requirement for anode materials that provide enhanced charge storage sites (high capacity) and accommodate fast charge transport (high rate capability) has increased. Herein, therefore, a preparation of nanocomposite as anode material is presented and an advanced HSC using it is thoroughly analyzed. The HSC comprises a mesoporous Nb2O5/carbon (m-Nb2O5-C) nanocomposite anode synthesized by a simple one-pot method using a block copolymer assisted self-assembly and commercial activated carbon (MSP-20) cathode under organic electrolyte. The m-Nb2O5-C anode provides high specific capacity with outstanding rate performance and cyclability, mainly stemming from its enhanced pseudocapacitive behavior through introduction of a carbon-coated mesostructure within a voltage range from 3.0 to 1.1 V (vs Li/Li(+)). The HSC using the m-Nb2O5-C anode and MSP-20 cathode exhibits excellent energy and power densities (74 W h kg(-1) and 18,510 W kg(-1)), with advanced cycle life (capacity retention: ∼90% at 1000 mA g(-1) after 1000 cycles) within potential range from 1.0 to 3.5 V. In particular, we note that the highest power density (18,510 W kg(-1)) of HSC is achieved at 15 W h kg(-1), which is the highest level among similar HSC systems previously reported. With further study, the HSCs developed in this work could be a next-generation energy-storage device, bridging the performance gap between conventional batteries and supercapacitors. PMID:25137384

  10. Branched artificial nanofinger arrays by mesoporous interfacial atomic rearrangement.

    PubMed

    Kong, Biao; Tang, Jing; Zhang, Yueyu; Selomulya, Cordelia; Gong, Xingao; Liu, Yang; Zhang, Wei; Yang, Jianping; Wang, Wenshuo; Sun, Xiaotian; Wang, Yufei; Zheng, Gengfeng; Zhao, Dongyuan

    2015-04-01

    The direct production of branched semiconductor arrays with highly ordered orientation has proven to be a considerable challenge over the last two decades. Here we report a mesoporous interfacial atomic rearrangement (MIAR) method to directly produce highly crystalline, finger-like branched iron oxide nanoarrays from the mesoporous nanopyramids. This method has excellent versatility and flexibility for heteroatom doping of metallic elements, including Sn, Bi, Mn, Fe, Co, Ni, Cu, Zn, and W, in which the mesoporous nanopyramids first absorb guest-doping molecules into the mesoporous channels and then convert the mesoporous pyramids into branching artificial nanofingers. The crystalline structure can provide more optoelectronic active sites of the nanofingers by interfacial atomic rearrangements of doping molecules and mesopore channels at the porous solid-solid interface. As a proof-of-concept, the Sn-doped Fe2O3 artificial nanofingers (ANFs) exhibit a high photocurrent density of ∼1.26 mA/cm(2), ∼5.25-fold of the pristine mesoporous Fe2O3 nanopyramid arrays. Furthermore, with surface chemical functionalization, the Sn-doped ANF biointerfaces allow nanomolar level recognition of metabolism-related biomolecules (∼5 nm for glutathione). This MIAR method suggests a new growth means of branched mesostructures, with enhanced optoelectronic applications. PMID:25764364

  11. Functionalized bimodal mesoporous silicas as carriers for controlled aspirin delivery

    SciTech Connect

    Gao Lin; Sun Jihong; Li Yuzhen

    2011-08-15

    The bimodal mesoporous silica modified with 3-aminopropyltriethoxysilane was performed as the aspirin carrier. The samples' structure, drug loading and release profiles were characterized with X-ray diffraction, scanning electron microscopy, N{sub 2} adsorption and desorption, Fourier transform infrared spectroscopy, TG analysis, elemental analysis and UV-spectrophotometer. For further exploring the effects of the bimodal mesopores on the drug delivery behavior, the unimodal mesoporous material MCM-41 was also modified as the aspirin carrier. Meantime, Korsmeyer-Peppas equation f{sub t}=kt{sup n} was employed to analyze the dissolution data in details. It is indicated that the bimodal mesopores are beneficial for unrestricted drug molecules diffusing and therefore lead to a higher loading and faster releasing than that of MCM-41. The results show that the aspirin delivery properties are influenced considerably by the mesoporous matrix, whereas the large pore of bimodal mesoporous silica is the key point for the improved controlled-release properties. - Graphical abstract: Loading (A) and release profiles (B) of aspirin in N-BMMs and N-MCM-41 indicated that BMMs have more drug loading capacity and faster release rate than that MCM-41. Highlights: > Bimodal mesoporous silicas (BMMs) and MCM-41 modified with amino group via post-treatment procedure. > Loading and release profiles of aspirin in modified BMMs and MCM-41. > Modified BMMs have more drug loading capacity and faster release rate than that modified MCM-41.

  12. Mesoporous silica material TUD-1 as a drug delivery system.

    PubMed

    Heikkilä, T; Salonen, J; Tuura, J; Hamdy, M S; Mul, G; Kumar, N; Salmi, T; Murzin, D Yu; Laitinen, L; Kaukonen, A M; Hirvonen, J; Lehto, V-P

    2007-02-22

    For the first time the feasibility of siliceous mesoporous material TUD-1 (Technische Universiteit Delft) for drug delivery was studied. Model drug, ibuprofen, was adsorbed into TUD-1 mesopores via a soaking procedure. Characterizations with nitrogen adsorption, XRD, TG, HPLC and DSC demonstrated the successful inclusion of ibuprofen into TUD-1 host. The amount of ibuprofen adsorbed into the nanoreservoir of TUD-1 material was higher than reported for other mesoporous silica drug carriers (drug/carrier 49.5 wt.%). Drug release studies in vitro (HBSS buffer pH 5.5) demonstrated a fast and unrestricted liberation of ibuprofen, with 96% released at 210 min of the dissolution assay. The drug dissolution profile of TUD-1 material with the random, foam-like three-dimensional mesopore network and high accessibility to the dissolution medium was found to be much faster (kinetic constant k = 10.7) and more diffusion based (release constant n = 0.64) compared to a mesoporous MCM-41 material with smaller, unidirectional mesopore channels (k = 4.7, n = 0.71). Also, the mesoporous carriers were found to significantly increase the dissolution rate of ibuprofen, when compared to the pure crystalline form of the drug (k = 0.6, n = 0.96). TUD-1 was constituted as a potential drug delivery device with fast release property, with prospective applications in the formulation of poorly soluble drug compounds. PMID:17046183

  13. Silica-based mesoporous nanoparticles for controlled drug delivery.

    PubMed

    Kwon, Sooyeon; Singh, Rajendra K; Perez, Roman A; Abou Neel, Ensanya A; Kim, Hae-Won; Chrzanowski, Wojciech

    2013-01-01

    Drug molecules with lack of specificity and solubility lead patients to take high doses of the drug to achieve sufficient therapeutic effects. This is a leading cause of adverse drug reactions, particularly for drugs with narrow therapeutic window or cytotoxic chemotherapeutics. To address these problems, there are various functional biocompatible drug carriers available in the market, which can deliver therapeutic agents to the target site in a controlled manner. Among the carriers developed thus far, mesoporous materials emerged as a promising candidate that can deliver a variety of drug molecules in a controllable and sustainable manner. In particular, mesoporous silica nanoparticles are widely used as a delivery reagent because silica possesses favourable chemical properties, thermal stability and biocompatibility. Currently, sol-gel-derived mesoporous silica nanoparticles in soft conditions are of main interest due to simplicity in production and modification and the capacity to maintain function of bioactive agents. The unique mesoporous structure of silica facilitates effective loading of drugs and their subsequent controlled release. The properties of mesopores, including pore size and porosity as well as the surface properties, can be altered depending on additives used to fabricate mesoporous silica nanoparticles. Active surface enables functionalisation to modify surface properties and link therapeutic molecules. The tuneable mesopore structure and modifiable surface of mesoporous silica nanoparticle allow incorporation of various classes of drug molecules and controlled delivery to the target sites. This review aims to present the state of knowledge of currently available drug delivery system and identify properties of an ideal drug carrier for specific application, focusing on mesoporous silica nanoparticles. PMID:24020012

  14. Incorporation of antimicrobial compounds in mesoporous silica film monolith.

    PubMed

    Izquierdo-Barba, Isabel; Vallet-Regí, María; Kupferschmidt, Natalia; Terasaki, Osamu; Schmidtchen, Artur; Malmsten, Martin

    2009-10-01

    Incorporation of the antimicrobial peptide LL-37 (LLGDFFRKSKEKIGKEFKRIVQRIKDFLRNLVPRTES), as well as low molecular weight antimicrobial chlorhexidine, into mesoporous silica was obtained using an EISA one-pot synthesis method. FTIR confirmed efficient encapsulation of both LL-37 and chlorhexidine into mesoporous silica, while XRD and TEM showed that antimicrobial agent incorporation can be achieved without greatly affecting the structure of the mesoporous silica. The modified mesoporous silica released LL-37 and chlorhexidine slowly, reaching maximum release after about 200 h. The release rate could also be controlled through incorporation of SH groups in the pore walls, adding to pore hydrophobicity and reducing the release rate by about 50% compared to the unmodified mesoporous silica. Mesoporous silica containing either LL-37 or chlorhexidine displayed potent bactericidal properties against both Gram-positive Staphylococcus aureus and Gram-negative Escherichia coli. While chlorhexidine-loaded mesoporous silica displayed an accompanying high toxicity, as judged from hemolysis, LDH release, and MTT assay, the corresponding material containing LL-37 showed very low toxicity by all these assays, comparable to that observed for mesoporous silica in the absence of antibacterial drug, as well as to the negative controls in the respective assays. Mesoporous silica containing LL-37 therefore holds potential as an implantable material or a surface coating for such materials, as it combines potent bactericidal action with low toxicity, important features for controlling implant-related infections, e.g., for multi-resistant pathogens or for cases where access to the infection site of systemically administered antibiotics is limited due to collagen capsule formation or other factors. PMID:19628277

  15. Silica-based mesoporous nanoparticles for controlled drug delivery

    PubMed Central

    Kwon, Sooyeon; Singh, Rajendra K; Perez, Roman A; Abou Neel, Ensanya A

    2013-01-01

    Drug molecules with lack of specificity and solubility lead patients to take high doses of the drug to achieve sufficient therapeutic effects. This is a leading cause of adverse drug reactions, particularly for drugs with narrow therapeutic window or cytotoxic chemotherapeutics. To address these problems, there are various functional biocompatible drug carriers available in the market, which can deliver therapeutic agents to the target site in a controlled manner. Among the carriers developed thus far, mesoporous materials emerged as a promising candidate that can deliver a variety of drug molecules in a controllable and sustainable manner. In particular, mesoporous silica nanoparticles are widely used as a delivery reagent because silica possesses favourable chemical properties, thermal stability and biocompatibility. Currently, sol-gel-derived mesoporous silica nanoparticles in soft conditions are of main interest due to simplicity in production and modification and the capacity to maintain function of bioactive agents. The unique mesoporous structure of silica facilitates effective loading of drugs and their subsequent controlled release. The properties of mesopores, including pore size and porosity as well as the surface properties, can be altered depending on additives used to fabricate mesoporous silica nanoparticles. Active surface enables functionalisation to modify surface properties and link therapeutic molecules. The tuneable mesopore structure and modifiable surface of mesoporous silica nanoparticle allow incorporation of various classes of drug molecules and controlled delivery to the target sites. This review aims to present the state of knowledge of currently available drug delivery system and identify properties of an ideal drug carrier for specific application, focusing on mesoporous silica nanoparticles. PMID:24020012

  16. Distributions of noble metal Pd and Pt in mesoporous silica

    NASA Astrophysics Data System (ADS)

    Arbiol, J.; Cabot, A.; Morante, J. R.; Chen, Fanglin; Liu, Meilin

    2002-10-01

    Mesoporous silica nanostructures have been synthesized and loaded with Pd and Pt catalytic noble metals. It is found that Pd forms small nanoclusters (3-5 nm) on the surface of the mesoporous structure whereas Pt impregnation results in the inclusion of Pt nanostructures within the silica hexagonal pores (from nanoclusters to nanowires). It is observed that these materials have high catalytic properties for CO-CH4 combustion, even in a thick film form. In particular, results indicate that the Pt and Pd dispersed in mesoporous silica are catalytically active as a selective filter for gas sensors.

  17. Mesoporous Trimetallic PtPdRu Spheres as Superior Electrocatalysts.

    PubMed

    Jiang, Bo; Ataee-Esfahani, Hamed; Li, Cuiling; Alshehri, Saad M; Ahamad, Tansir; Henzie, Joel; Yamauchi, Yusuke

    2016-05-17

    Mesoporous Trimetallic PtPdRu Spheres with well-defined spherical morphology and uniformly sized pores were synthesized in an aqueous solution using ascorbic acid as the reducing agent and triblock copolymer F127 as the pore directing agent. These mesoporous PtPdRu spheres exhibited enhanced electrocatalytic activity compared to commercial Pt black, resulting in a ∼4.9 times improvement in mass activity for the methanol oxidation reaction. The excellent electrocatalytic activity and stability are due to the unique mesoporous architecture and electronic landscape between different elements. PMID:27072776

  18. Crystalline mesoporous zirconia catalysts having stable tetragonal pore wall structure

    DOEpatents

    Sachtler, Wolfgang M. H.; Huang, Yin-Yan

    1998-01-01

    Methods for the preparation of new sulfated mesoporous zirconia materials/catalysts with crystalline pore walls of predominantly tetragonal crystal structure, characterized by nitrogen physisorption measurement, X-ray diffraction, transmission electron microscopy and catalytic tests using n-butane isomerization to iso-butane and alkylation of 1-naphthol with 4-tert-butylstyrene as probe reactions. Sulfate deposition is preferred for the transformation of a mesoporous precursor with amorphous pore walls into a material with crystalline pore walls maintaining the mesoporous characteristics.

  19. Crystalline mesoporous zirconia catalysts having stable tetragonal pore wall structure

    DOEpatents

    Sachtler, W.M.H.; Huang, Y.Y.

    1998-07-28

    Methods are disclosed for the preparation of new sulfated mesoporous zirconia materials/catalysts with crystalline pore walls of predominantly tetragonal crystal structure, characterized by nitrogen physical sorption measurement, X-ray diffraction, transmission electron microscopy and catalytic tests using n-butane isomerization to iso-butane and alkylation of 1-naphthol with 4-tert-butylstyrene as probe reactions. Sulfate deposition is preferred for the transformation of a mesoporous precursor with amorphous pore walls into a material with crystalline pore walls maintaining the mesoporous characteristics. 17 figs.

  20. Gated Silica Mesoporous Materials in Sensing Applications.

    PubMed

    Sancenón, Félix; Pascual, Lluís; Oroval, Mar; Aznar, Elena; Martínez-Máñez, Ramón

    2015-08-01

    Silica mesoporous supports (SMSs) have a large specific surface area and volume and are particularly exciting vehicles for delivery applications. Such container-like structures can be loaded with numerous different chemical substances, such as drugs and reporters. Gated systems also contain addressable functions at openings of voids, and cargo delivery can be controlled on-command using chemical, biochemical or physical stimuli. Many of these gated SMSs have been applied for drug delivery. However, fewer examples of their use in sensing protocols have been reported. The approach of applying SMSs in sensing uses another concept-that of loading pores with a reporter and designing a capping mechanism that is selectively opened in the presence of a target analyte, which results in the delivery of the reporter. According to this concept, we provide herein a complete compilation of published examples of probes based on the use of capped SMSs for sensing. Examples for the detection of anions, cations, small molecules and biomolecules are provided. The diverse range of gated silica mesoporous materials presented here highlights their usefulness in recognition protocols. PMID:26491626

  1. Gated Silica Mesoporous Materials in Sensing Applications

    PubMed Central

    Sancenón, Félix; Pascual, Lluís; Oroval, Mar; Aznar, Elena; Martínez-Máñez, Ramón

    2015-01-01

    Silica mesoporous supports (SMSs) have a large specific surface area and volume and are particularly exciting vehicles for delivery applications. Such container-like structures can be loaded with numerous different chemical substances, such as drugs and reporters. Gated systems also contain addressable functions at openings of voids, and cargo delivery can be controlled on-command using chemical, biochemical or physical stimuli. Many of these gated SMSs have been applied for drug delivery. However, fewer examples of their use in sensing protocols have been reported. The approach of applying SMSs in sensing uses another concept—that of loading pores with a reporter and designing a capping mechanism that is selectively opened in the presence of a target analyte, which results in the delivery of the reporter. According to this concept, we provide herein a complete compilation of published examples of probes based on the use of capped SMSs for sensing. Examples for the detection of anions, cations, small molecules and biomolecules are provided. The diverse range of gated silica mesoporous materials presented here highlights their usefulness in recognition protocols. PMID:26491626

  2. Optically tunable chiral nematic mesoporous cellulose films.

    PubMed

    Schlesinger, Maik; Hamad, Wadood Y; MacLachlan, Mark J

    2015-06-21

    Demand for sustainable functional materials has never been larger. The introduction of functionality into pure cellulose might be one step forward in this field as it is one of the most abundant natural biopolymers. In this paper, we demonstrate a straightforward and scalable way to produce iridescent, mesoporous cellulose membranes with tunable colors and porosity. Concomitant assembly of cellulose nanocrystals (CNCs) and condensation of silica precursors results in CNC-silica composites with chiral nematic structures and tunable optical properties. Removal of the stabilizing silica matrix by alkaline or acid treatment gives access to novel chiral nematic mesoporous cellulose (CNMC) films. Importantly, the optical properties and the mesoporosity can be controlled by either varying the silica-to-CNC ratio, or by varying the substrate used during the evaporation-induced self-assembly process. In order to introduce additional functionality, CNMC has been used to stabilize gold nanoparticles with three different concentrations by wet impregnation. These materials are stable in water and can potentially function in sensors, tissue engineering or functional membranes. PMID:25972020

  3. Polycarbonate based three-phase nanocomposite dielectrics

    NASA Astrophysics Data System (ADS)

    Sain, P. K.; Goyal, R. K.; Prasad, Y. V. S. S.; Bhargava, A. K.

    2016-08-01

    Three-phase polycarbonate (PC) matrix nanocomposites are prepared using the solution method. One of the nanocomposite fillers is dielectric and the other is conducting. Lead zirconate titanate (PZT) is used as the dielectric filler. The conducting fillers, nano-Cu and multi-walled carbon nanotubes (MWCNTs), are used to make two different nanocomposites, MWCNT–PZT–PC and Cu–PZT–PC. The prepared nanocomposites are characterized using density measurement, x-ray diffractometry, scanning electron microscopy, energy dispersive x-ray spectroscopy, and differential scanning calorimetry. Percolation is absent in both three-phase nanocomposites within the study’s concentration window of conducting fillers. The dielectric properties of the nanocomposites are evaluated using a precision impedance analyser. The dielectric constant of the Cu–PZT–PC nanocomposite increases to 14 (a dissipation factor of 0.17), whereas in the case of the MWCNT–PZT–PC nanocomposite it increases to 8.5 (a dissipation factor of 0.002). The melting point of both nanocomposites decreases with respect to the control PC. The frequency (1 kHz to 1 MHz) and temperature (room temperature to 200 °C) dependence of the dielectric constant and dissipation factor are examined. For the Cu–PZT–PC nanocomposites, the dielectric constant decreases with increasing frequency, whereas in the case of the MWCNT–PZT–PC nanocomposites the dielectric constant is almost constant. The dielectric constant and dissipation factor exhibit a slight temperature dependence.

  4. Shape memory polyurethane nanocomposites

    NASA Astrophysics Data System (ADS)

    Cao, Feina

    stress could be tailored by the processing conditions. The recovery stress increased with decrease of stretching rate, and increase of stretching temperature and stretch ratio. The recovery stress of polyurethane/clay nanocomposites largely depended on the degree of clay exfoliation. Higher recovery stress was found in nanocomposites with better clay dispersion. The dependence of stress relaxation on stretching conditions, clay type, and clay content was also investigated and related to shape recovery stress. It was found that stress relaxation occurred more easily in the presence of nanoclay.

  5. Nanocomposite Sensors for Food Packaging

    NASA Astrophysics Data System (ADS)

    Avella, Maurizio; Errico, Maria Emanuela; Gentile, Gennaro; Volpe, Maria Grazia

    Nowadays nanotechnologies applied to the food packaging sector find always more applications due to a wide range of benefits that they can offer, such as improved barrier properties, improved mechanical performance, antimicrobial properties and so on. Recently many researches are addressed to the set up of new food packaging materials, in which polymer nanocomposites incorporate nanosensors, developing the so-called "smart" packaging. Some examples of nanocomposite sensors specifically realised for the food packaging industry are reported. The second part of this work deals with the preparation and characterisation of two new polymer-based nanocomposite systems that can be used as food packaging materials. Particularly the results concerning the following systems are illustrated: isotactic polypropylene (iPP) filled with CaCO3 nanoparticles and polycaprolactone (PCL) filled with SiO2 nanoparticles.

  6. Stretchable piezoelectric nanocomposite generator

    NASA Astrophysics Data System (ADS)

    Park, Kwi-Il; Jeong, Chang Kyu; Kim, Na Kyung; Lee, Keon Jae

    2016-06-01

    Piezoelectric energy conversion that generate electric energy from ambient mechanical and vibrational movements is promising energy harvesting technology because it can use more accessible energy resources than other renewable natural energy. In particular, flexible and stretchable piezoelectric energy harvesters which can harvest the tiny biomechanical motions inside human body into electricity properly facilitate not only the self-powered energy system for flexible and wearable electronics but also sensitive piezoelectric sensors for motion detectors and in vivo diagnosis kits. Since the piezoelectric ZnO nanowires (NWs)-based energy harvesters (nanogenerators) were proposed in 2006, many researchers have attempted the nanogenerator by using the various fabrication process such as nanowire growth, electrospinning, and transfer techniques with piezoelectric materials including polyvinylidene fluoride (PVDF) polymer and perovskite ceramics. In 2012, the composite-based nanogenerators were developed using simple, low-cost, and scalable methods to overcome the significant issues with previously-reported energy harvester, such as insufficient output performance and size limitation. This review paper provides a brief overview of flexible and stretchable piezoelectric nanocomposite generator for realizing the self-powered energy system with development history, power performance, and applications.

  7. Graphene/Polymer Nanocomposites

    NASA Astrophysics Data System (ADS)

    Macosko, Chris

    2010-03-01

    Graphite has attracted large attention as a reinforcement for polymers due to its ability to modify electrical conductivity, mechanical and gas barrier properties of host polymers and its potentially lower cost than carbon nanotubes. If graphite can be exfoliated into atomically thin graphene sheets, it is possible to achieve the highest property enhancements at the lowest loading. However, small spacing and strong van der Waals forces between graphene layers make exfoliation of graphite via conventional composite manufacturing strategies challenging. Recently, two different approaches to obtain exfoliated graphite prior to blending were reported: thermal treatment (Schniepp et al., JACS 2006) and chemical modification (Stankovich et al., J Mat Chem 2006). Both start from graphite oxide. We will describe and evaluate these exfoliation approaches and the methods used to produce graphene reinforced thermoplastics, particularly polyester, polycarbonate and polyurethane nanocomposites. Three different dispersion methods - melt blending, solution mixing and in-situ polymerization -- are compared. Characterization of dispersion quality is illustrated with TEM, rheology and in electrical conductivity, tensile modulus and gas barrier property improvement.

  8. Aerogel nanocomposite materials

    SciTech Connect

    Hunt, A.J.; Ayers, M.; Cao, W.

    1995-05-01

    Aerogels are porous, low density, nanostructured solids with many unusual properties including very low thermal conductivity, good transparency, high surface area, catalytic activity, and low sound velocity. This research is directed toward developing new nanocomposite aerogel materials for improved thermal insulation and several other applications. A major focus of the research has been to further increase the thermal resistance of silica aerogel by introducing infrared opacification agents into the aerogel to produce a superinsulating composite material. Opacified superinsulating aerogel permit a number of industrial applications for aerogel-based insulation. The primary benefits from this recently developed superinsulating composite aerogel insulation are: to extend the range of applications to higher temperatures, to provide a more compact insulation for space sensitive-applications, and to lower costs of aerogel by as much as 30%. Superinsulating aerogels can replace existing CFC-containing polyurethane in low temperature applications to reduce heat losses in piping, improve the thermal efficiency of refrigeration systems, and reduce energy losses in a variety of industrial applications. Enhanced aerogel insulation can also replace steam and process pipe insulation in higher temperature applications to substantially reduce energy losses and provide much more compact insulation.

  9. Polariton dispersion in nanocomposite materials

    SciTech Connect

    Wilson, K. S. Joseph Revathy, V.

    2015-06-24

    The several optical properties of crystals are modified due to nonlinearity associated with high intensity of the incident radiation. In the present work, the linear and nonlinear optical characterization of the nanocomposite materials are also discussed in detail. We explore the possibilities of nonlinear effects in the optical parameters in nanocomposite materials. New modes on the polaritonic gap where the propagation of electromagnetic wave is forbidden, are obtained due to nonlinearity. The presence of gap mode shows the propagation of electromagnetic radiation which may be exploited in optical communications.

  10. Complex dynamics in polymer nanocomposites

    NASA Astrophysics Data System (ADS)

    Srivastava, S.; Kandar, A. K.; Basu, J. K.; Mukhopadhyay, M. K.; Lurio, L. B.; Narayanan, S.; Sinha, S. K.

    2009-02-01

    Polymer nanocomposites offer the potential to create a new type of hybrid material with unique thermal, optical, or electrical properties. Understanding their structure, phase behavior, and dynamics is crucial for realizing such potentials. In this work we provide an experimental insight into the dynamics of such composites in terms of the temperature, wave vector, and volume fraction of nanoparticles, using multispeckle synchrotron x-ray photon correlation spectroscopy measurements on gold nanoparticles embedded in polymethylmethacrylate. Detailed analysis of the intermediate scattering functions reveals possible existence of an intrinsic length scale for dynamic heterogeneity in polymer nanocomposites similar to that seen in other soft materials like colloidal gels and glasses.

  11. Biobased and biodegradable polymer nanocomposites

    NASA Astrophysics Data System (ADS)

    Qiu, Kaiyan

    In this dissertation, various noncrosslinked and crosslinked biobased and biodegradable polymer nanocomposites were fabricated and characterized. The properties of these polymer nanocomposites, and their relating mechanisms and corresponding applications were studied and discussed in depth. Chapter 1 introduces the research background and objectives of the current research. Chapter 2 presents the development of a novel low cost carbon source for bacterial cellulose (BC) production and fabrication and characterization of biobased polymer nanocomposites using produced BC and soy protein based resins. The carbon source, soy flour extract (SFE), was obtained from defatted soy flour (SF) and BC yield achieved using SFE medium was high. The results of this study showed that SFE consists of five sugars and Acetobacter xylinum metabolized sugars in a specific order. Chapter 3 discusses the fabrication and characterization of biodegradable polymer nanocomposites using BC and polyvinyl alcohol (PVA). These polymer nanocomposites had excellent tensile and thermal properties. Crosslinking of PVA using glutaraldehyde (GA) not only increased the mechanical and thermal properties but the water-resistance. Chapter 4 describes the development and characterization of microfibrillated cellulose (MFC) based biodegradable polymer nanocomposites by blending MFC suspension with PVA. Chemical crosslinking of the polymer nanocomposites was carried out using glyoxal to increase the mechanical and thermal properties as well as to make the PVA partially water-insoluble. Chapter 5 reports the development and characterization of halloysite nanotube (HNT) reinforced biodegradable polymer nanocomposites utilizing HNT dispersion and PVA. Several separation techniques were used to obtain individualized HNT dispersion. The results indicated uniform dispersion of HNTs in both PVA and malonic acid (MA) crosslinked PVA resulted in excellent mechanical and thermal properties of the materials, especially

  12. Microwave-induced synthesis of highly dispersed gold nanoparticles within the pore channels of mesoporous silica

    NASA Astrophysics Data System (ADS)

    Gu, Jinlou; Fan, Wei; Shimojima, Atsushi; Okubo, Tatsuya

    2008-04-01

    Highly dispersed gold nanoparticles have been incorporated into the pore channels of SBA-15 mesoporous silica through a newly developed strategy assisted by microwave radiation (MR). The sizes of gold are effectively controlled attributed to the rapid and homogeneous nucleation, simultaneous propagation and termination of gold precursor by MR. Diol moieties with high dielectric and dielectric loss constants, and hence a high microwave activation, were firstly introduced to the pore channels of SBA-15 by a simple addition reaction between amino group and glycidiol and subsequently served as the reduction centers for gold nanoparticles. Extraction of the entrapped gold from the nanocomposite resulted in milligram quantities of gold nanoparticles with low dispersity. The successful assembly process of diol groups and formation of gold nanoparticles were monitored and tracked by solid-state NMR and UV-vis measurements. Characterization by small angle X-ray diffraction (XRD) and transmission electron microscopy (TEM) indicated that the incorporation of gold nanoparticles would not breakup the structural integrity and long-range periodicity of SBA-15. The gold nanoparticles had a narrow size distribution with diameters in the size range of 5-10 nm through TEM observation. The average particles size is 7.9 nm via calculation by the Scherrer formula and TEM measurements. Nitrogen adsorption and desorption isotherms gave further evidence that the employed method was efficient and gold nanoparticles were successfully incorporated into the pore channels of SBA-15.

  13. Gated magnetic mesoporous silica nanoparticles for intracellular enzyme-triggered drug delivery.

    PubMed

    An, Na; Lin, Huiming; Yang, Chunyu; Zhang, Ting; Tong, Ruihan; Chen, Yuhua; Qu, Fengyu

    2016-12-01

    The targeting drug release is significant to the anticancer treatment. In this context, the redox-responsive drug delivery has attracted most attention owing to the intracellular reductive environment, such as the high concentration of glutathione reductase in many cancer cells. Herein, a glutathione sensitive drug delivery nanoplatform was constructed by using core-shell mesoporous silica nanocomposite (Fe3O4@mSiO2) as carrier. By a simple silane coupling reaction, the glutathione cleavable diselenide linker has been prepared and grafted on to Fe3O4@mSiO2 to insure the encapsulation of anticancer drug doxorubicin. The detail release kinetics studies reveal the glutathione triggered drug release, which could be further adjusted by varying the amount of diselenide linker. To improve the tumor-targeting, folic acid was grafted. The cellular uptake and drug release investigation was carried out using HeLa (cervical cancer cell line) as the model cancer cell and L02 and HUVEC (human hepatic cell line and human umbilical vein endothelial cells, non-cancerous cell lines) as control, indicating the enhanced cytotoxicity toward HeLa cells that benefits from the fast endocytosis and enhanced cellular drug release owing to their overexpressing folic acid receptors and high concentration of glutathione. Associating with the magnetic targeting, these novel nanomaterials are expected to be promising in the potential application of tumor-targeting therapy. PMID:27612716

  14. Critical aspects in the production of periodically ordered mesoporous titania thin films.

    PubMed

    Soler-Illia, Galo J A A; Angelomé, Paula C; Fuertes, M Cecilia; Grosso, David; Boissiere, Cedric

    2012-04-21

    Periodically ordered mesoporous titania thin films (MTTF) present a high surface area, controlled porosity in the 2-20 nm pore diameter range and an amorphous or crystalline inorganic framework. These materials are nowadays routinely prepared by combining soft chemistry and supramolecular templating. Photocatalytic transparent coatings and titania-based solar cells are the immediate promising applications. However, a wealth of new prospective uses have emerged on the horizon, such as advanced catalysts, perm-selective membranes, optical materials based on plasmonics and photonics, metamaterials, biomaterials or new magnetic nanocomposites. Current and novel applications rely on the ultimate control of the materials features such as pore size and geometry, surface functionality and wall structure. Even if a certain control of these characteristics has been provided by the methods reported so far, the needs for the next generation of MTTF require a deeper insight in the physical and chemical processes taking place in their preparation and processing. This article presents a critical discussion of these aspects. This discussion is essential to evolve from know-how to sound knowledge, aiming at a rational materials design of these fascinating systems. PMID:22419250

  15. Mesoporous carbon incorporated metal oxide nanomaterials as supercapacitor electrodes.

    PubMed

    Jiang, Hao; Ma, Jan; Li, Chunzhong

    2012-08-01

    Supercapacitors have attracted huge attention in recent years as they have the potential to satisfy the demand of both huge energy and power density in many advanced technologies. However, poor conductivity and cycling stability remains to be the major challenge for its widespread application. Various strategies have been developed for meeting the ever-increasing energy and power demands in supercapacitors. This Research News article aims to review recent progress in the development of mesoporous carbon incorporated metal oxide nanomaterials, especially metal oxide nanoparticles confined in ordered mesoporous carbon and 1D metal oxides coated with a layer of mesoporous carbon for high-performance supercapacitor applications. In addition, a recent trend in supercapacitor development - hierarchical porous graphitic carbons (HPGC) combining macroporous cores, mesoporous walls, and micropores as an excellent support for metal oxides - is also discussed. PMID:23030034

  16. Novel method to incorporate Si into monodispersed mesoporous carbon spheres.

    PubMed

    Yano, Kazuhisa; Tatsuda, Narihito; Masuda, Takashi; Shimoda, Tatsuya

    2016-10-01

    Liquid silicon precursor is used as a silicon source and very simple and easy method for the incorporation of Si into mesoporous carbon spheres is presented. By using capillary condensation, the liquid precursor, Cyclopentasilane, penetrates into mesopores of carbon spheres homogeneously and subsequent heating brings the decomposition of the precursor and the formation of silicon inside meso-channels of carbon even though the decomposition is done much higher than the boiling point of the precursor. The homogeneous distribution of silicon is verified by EDX mapping of the composite as well as SEM observation of the calcined one. More than 45wt% of Si can be incorporated into mesopores by just one operation. The Si@mesoporous carbon composite works as an anode for a Lithium ion battery. PMID:27344486

  17. Synthesis of mesoporous nano-hydroxyapatite by using zwitterions surfactant

    EPA Science Inventory

    Mesoporous nano-hydroxyapatite (mn-HAP) was successfully synthesized via a novel micelle-templating method using lauryl dimethylaminoacetic acid as zwitterionic surfactant. The systematic use of such a surfactant in combination with microwave energy inputenables the precise contr...

  18. Thermally stable crystalline mesoporous metal oxides with substantially uniform pores

    SciTech Connect

    Wiesner, Ulrich; Orilall, Mahendra Christopher; Lee, Jinwoo; DiSalvo, Jr., Francis J

    2015-01-27

    Highly crystalline metal oxide-carbon composites, as precursors to thermally stable mesoporous metal oxides, are coated with a layer of amorphous carbon. Using a `one-pot` method, highly crystalline metal oxide-carbon composites are converted to thermally stable mesoporous metal oxides, having highly crystalline mesopore walls, without causing the concomitant collapse of the mesostructure. The `one-pot` method uses block copolymers with an sp or sp 2 hybridized carbon containing hydrophobic block as structure directing agents which converts to a sturdy, amorphous carbon material under appropriate heating conditions, providing an in-situ rigid support which maintains the pores of the oxides intact while crystallizing at temperatures as high as 1000 deg C. A highly crystalline metal oxide-carbon composite can be heated to produce a thermally stable mesoporous metal oxide consisting of a single polymorph.

  19. Enzyme catalytic membrane based on a hybrid mesoporous membrane.

    PubMed

    Fu, Wensheng; Yamaguchi, Akira; Kaneda, Hideaki; Teramae, Norio

    2008-02-21

    Immobilization of glucose oxidase (GOD) within a hybrid mesoporous membrane with 12 nm pore diameter was successfully achieved, resulting in catalytically high efficiency during flow of a glucose solution across the membrane. PMID:18253526

  20. Mesoporous silicates: Materials science and biological applications

    NASA Astrophysics Data System (ADS)

    Roggers, Robert Anthony

    This thesis dissertation presents the collective research into the advancement of mesoporous silicate particles as biointerface devices, the development of new materials and the application of these particles as solid supports for heterogeneous catalysis. Mesoporous silica has been utilized in the aforementioned applications due to several reasons; the first being the ability to achieve high surface areas (500 - 1000 m2 g-1) with controlled pore sizes and particle morphology. Another reason for their popularity is their robustness in applications of heterogeneous catalysis and the ability to functionalize the surface with a wide variety of organic functional groups. In the field of biointerface devices, mesoporous silica nanoparticles represent a class of materials that exhibit high biocompatibility. In addition, the ability to functionalize the surfaces (outer surface and pore interiors) allows the particles to be targeted to specific cell types as well as the ability to release many different therapeutic molecules under specific stimuli. A unique particle coating consisting of a chemically cleavable lipid bilayer that allows for the encapsulation of a fluorescent molecule and increases the biocompatibility of the particle has been developed. The lipid bilayer coated mesoporous silica nanoparticle (LB-MSN) was characterized using X-ray diffraction, transmission electron microscopy and nitrogen `sorption isotherms. The finished LB-MSN was then incubated with mammalian cells in order to prove their biocompatibility. Confocal micrographs demonstrate the endocytosis of the particles into the cells. In addition the micrographs also show that the LB-MSNs are separate from the endosomal compartments, however due to the lipophilic nature of the dye used to label the endosome there is some debate regarding this conclusion. The lipid bilayer coating was then applied to a large pore MSN (l-MSN) which had been previously shown to cause lysis of red blood cells (RBCs) at low

  1. Near-infrared emission from mesoporous crystalline germanium

    NASA Astrophysics Data System (ADS)

    Boucherif, Abderraouf; Korinek, Andreas; Aimez, Vincent; Arès, Richard

    2014-10-01

    Mesoporous crystalline germanium was fabricated by bipolar electrochemical etching of Ge wafer in HF-based electrolyte. It yields uniform mesoporous germanium layers composed of high density of crystallites with an average size 5-7 nm. Subsequent extended chemical etching allows tuning of crystallites size while preserving the same chemical composition. This highly controllable nanostructure exhibits photoluminescence emission above the bulk Ge bandgap, in the near-infrared range (1095-1360nm) with strong evidence of quantum confinement within the crystallites.

  2. Simple synthesis of mesoporous boron nitride with strong cathodoluminescence emission

    SciTech Connect

    Meng, Xiang-Lin; Lun, Ning; Qi, Yong-Xin; Zhu, Hui-Ling; Han, Fu-Dong; Yin, Long-Wei; Fan, Run-Hua; Bai, Yu-Jun; Bi, Jian-Qiang

    2011-04-15

    Mesoporous BN was prepared at 550 {sup o}C for 10 h or so via a simple reaction between NaBH{sub 4} and CO(NH{sub 2}){sub 2}. X-ray diffraction demonstrates the formation of t-BN with lattice constants a=2.46 and c=6.67 A. High-resolution transmission electron microscopy displays a lot of porous films in the product, which possesses a high surface area of 219 m{sup 2} g{sup -1} and a pore size primarily around 3.8 nm tested by nitrogen adsorption-desorption method. The mesoporous BN exhibits a strong luminescence emission around 3.41 eV in the cathodoluminescence spectra, a high stability in both morphology and structure, and good oxidation resistance up to 800 {sup o}C. The byproducts generated during the reaction are responsible for the formation of the mesoporous BN. -- Graphical abstract: The mesoporous BN with a high specific surface area of 219 m{sup 2} g{sup -1} exhibits a strong luminescence emission around 3.41 eV in the CL spectra, high thermal stability in both morphology and structure, and good oxidation resistance up to 800 {sup o}C. Display Omitted Research highlights: Mesoporous BN was prepared by a simple reaction between NaBH{sub 4} and CO(NH{sub 2}){sub 2} at 550 {sup o}C. The mesoporous BN possesses a high surface area of 219 m{sup 2} g{sup -1}. The mesoporous BN exhibits a strong luminescence emission around 3.41 eV. The mesoporous BN has high stability and good oxidation resistance up to 800 {sup o}C.

  3. Solar hydrogen and solar electricity using mesoporous materials

    NASA Astrophysics Data System (ADS)

    Mahoney, Luther

    The development of cost-effective materials for effective utilization of solar energy is a major challenge for solving the energy problems that face the world. This thesis work relates to the development of mesoporous materials for solar energy applications in the areas of photocatalytic water splitting and the generation of electricity. Mesoporous materials were employed throughout the studies because of their favorable physico-chemical properties such as high surface areas and large porosities. The first project was related to the use of a cubic periodic mesoporous material, MCM-48. The studies showed that chromium loading directly affected the phase of mesoporous silica formed. Furthermore, within the cubic MCM-48 structure, the loading of polychromate species determined the concentration of solar hydrogen produced. In an effort to determine the potential of mesoporous materials, titanium dioxide was prepared using the Evaporation-Induced Self-Assembly (EISA) synthetic method. The aging period directly determined the amount of various phases of titanium dioxide. This method was extended for the preparation of cobalt doped titanium dioxide for solar simulated hydrogen evolution. In another study, metal doped systems were synthesized using the EISA procedure and rhodamine B (RhB) dye sensitized and metal doped titania mesoporous materials were evaluated for visible light hydrogen evolution. The final study employed various mesoporous titanium dioxide materials for N719 dye sensitized solar cell (DSSC) materials for photovoltaic applications. The materials were extensively characterized using powder X-ray diffraction (XRD), nitrogen physisorption, diffuse reflectance spectroscopy (DRS), UV-Vis spectroscopy, Fourier-Transform-Infrared Spectroscopy (FT-IR), Raman spectroscopy, chemisorption, photoluminescence (PL), X-ray photoelectron spectroscopy (XPS), and transmission electron microscopy (TEM). In addition, photoelectrochemical measurements were completed using

  4. In-situ immobilization of enzymes in mesoporous silicas

    NASA Astrophysics Data System (ADS)

    Santalla, Esther; Serra, Elías; Mayoral, Alvaro; Losada, José; Blanco, Rosa M.; Díaz, Isabel

    2011-04-01

    Lipase from Candida antarctica B, horseradish peroxidase and laccase have been entrapped in silica cages rising mesoporous structures. Lipase and laccase yielded the highest structured mesoporous material whereas horseradish peroxidase may have altered the symmetry giving as a result mesocelullar foam (MCF) type of cages. The possible effect in the final structure of the material of the nature, size and surface structure of the proteins as well as the presence of various additives in the enzyme extracts is currently under investigations.

  5. Preparation, characterization, and electrochemical application of mesoporous copper oxide

    SciTech Connect

    Cheng, Liang; Shao, Mingwang; Chen, Dayan; Zhang, Yuzhong

    2010-02-15

    Mesoporous CuO was successfully synthesized via thermal decomposition of CuC{sub 2}O{sub 4} precursors. These products had ring-like morphology, which was made up of nanoparticles with the average diameter of 40 nm. The electrochemical experiments showed that the mesoporous CuO decreased the overvoltage of the electrode and increased electron transference in the measurement of dopamine.

  6. Near-infrared emission from mesoporous crystalline germanium

    SciTech Connect

    Boucherif, Abderraouf; Aimez, Vincent; Arès, Richard; Korinek, Andreas

    2014-10-15

    Mesoporous crystalline germanium was fabricated by bipolar electrochemical etching of Ge wafer in HF-based electrolyte. It yields uniform mesoporous germanium layers composed of high density of crystallites with an average size 5-7 nm. Subsequent extended chemical etching allows tuning of crystallites size while preserving the same chemical composition. This highly controllable nanostructure exhibits photoluminescence emission above the bulk Ge bandgap, in the near-infrared range (1095-1360nm) with strong evidence of quantum confinement within the crystallites.

  7. Antibacterial mesoporous molecular sieves modified with polymeric N-halamine.

    PubMed

    Wang, Yingfeng; Li, Lin; Liu, Ying; Ren, Xuehong; Liang, Jie

    2016-12-01

    In this research, a new kind of porous N-halamine material with high antibacterial efficacies was prepared. Poly [5,5-dimethyl-3-(3'-triethoxysilylpropyl)-hydantoin] (PSPH), an N-halamine precursor, was synthesized and grafted onto the surface of mesoporous molecular sieves (SBA-15). The mesoporous molecular sieves modified with the N-halamine polymer could be rendered biocidal upon exposure to dilute household bleach. The modified mesoporous molecular sieves were characterized by SEM, TEM, FTIR, XPS, TGA, XRD and BET analysis. It was found that the PSPH has been successfully grafted on the surface of mesoporous molecular sieves, and the morphology and structure of the modified mesoporous molecular sieves were slightly affected. The N-halamine modified mesoporous molecular sieves showed excellent antibacterial property, and inactivated 100% of S. aureus and E. coli O157:H7 with 8.05 and 7.92 log reductions within 1min of contact, respectively. The modified SBA-15 with high-antibacterial efficiency has potential application in water treatment and biomaterials areas. PMID:27612805

  8. Hierarchical organization and molecular diffusion in gold nanorod/silica supercrystal nanocomposites.

    PubMed

    Hamon, Cyrille; Sanz-Ortiz, Marta N; Modin, Evgeny; Hill, Eric H; Scarabelli, Leonardo; Chuvilin, Andrey; Liz-Marzán, Luis M

    2016-04-14

    Hierarchical organization of gold nanorods was previously obtained on a substrate, allowing precise control over the morphology of the assemblies and macroscale spatial arrangement. Herein, a thorough description of these gold nanorod assemblies and their orientation within supercrystals is presented together with a sol-gel technique to protect the supercrystals with mesoporous silica films. The internal organization of the nanorods in the supercrystals was characterized by combining focused ion beam ablation and scanning electron microscopy. A mesoporous silica layer is grown both over the supercrystals and between the individual lamellae of gold nanorods inside the structure. This not only prevented the detachment of the supercrystal from the substrate in water, but also allowed small molecule analytes to infiltrate the structure. These nanocomposite substrates show superior Raman enhancement in comparison with gold supercrystals without silica owing to improved accessibility of the plasmonic hot spots to analytes. The patterned supercrystal arrays with enhanced optical and mechanical properties obtained in this work show potential for the practical implementation of nanostructured devices in spatially resolved ultradetection of biomarkers and other analytes. PMID:26961684

  9. Synthesis, characterization and magnetic behavior of Co/MCM-41 nano-composites

    SciTech Connect

    Cuello, N.; Elías, V.; Crivello, M.; Oliva, M.; Eimer, G.

    2013-09-15

    Synthesis, structure and magnetic properties of Co/MCM-41 as magnetic nano-composites have been investigated. Mesoporous materials with different degrees of metal loading were prepared by wet impregnation and characterized by ICP, XRD, N{sub 2} adsorption, UV–vis DRS, TPR and EPMA-EDS. Cobalt oxide clusters and Co{sub 3}O{sub 4} nano-particles could be confined inside the mesopores of MCM-41, being this fact favored by the Co loading increasing. In addition, larger crystals of Co{sub 3}O{sub 4} detectable by XRD also grow on the surface when the Co loading is enhanced. The magnetic characterization was performed in a SQUID magnetometer using a maximum magnetic applied field µ{sub 0}Ha=1 T. While the samples with the higher Co loadings showed a behavior typically paramagnetic, a superparamagnetic contribution is more notorious for lower loadings, suggesting high Co species dispersion. - Graphical abstract: Room temperature hysteresis loops as a function of the Co content. Display Omitted - Highlights: • Co species as isolated Co{sup 2+}, oxide clusters and Co{sub 3}O{sub 4} nano-particles were detected. • For higher Co loads were detected, by XRD, Co{sub 3}O{sub 4} particles on the external surface. • The confining of Co species inside the mesopores was achieved by increasing Co load. • Paramagnetism from oxide clusters/nano-particles becomes dominant for higher Co loads. • Superparamagnetism can be assigned to Co species of small size and finely dispersed.

  10. Concepts for smart nanocomposite materials

    NASA Astrophysics Data System (ADS)

    Pammi, SriLaxmi; Brown, Courtney; Datta, Saurabh; Kirikera, Goutham R.; Schulz, Mark J.

    2003-10-01

    This paper explores concepts for new smart materials that have extraordinary properties based on nanotechnology. Carbon and boron nitride nanotubes in theory can be used to manufacture fibers that have piezoelectric, pyroelectric, piezoresistive, and electrochemical field properties. Smart nanocomposites designed using these fibers will sense and respond to elastic, thermal, and chemical fields in a positive human-like way to improve the performance of structures, devices, and possibly humans. Remarkable strength, morphing, cooling, energy harvesting, strain and temperature sensing, chemical sensing and filtering, and high natural frequencies and damping will be the properties of these new materials. Synthesis of these unique atomically precise nanotubes, fibers, and nanocomposites is at present challenging and expensive, however, there is the possibility that we can synthesize the strongest and lightest actuators and most efficient sensors man has ever made. A particular advantage of nanotube transducers is their very high load bearing capability. Carbon nanotube electrochemical actuators have a predicted energy density at low frequencies that is thirty times greater than typical piezoceramic materials while boron nitride nanotubes are insulators and can operate at high temperatures, but they have a predicted piezoelectric induced stress constant that is about twenty times smaller than piezoceramic materials. Carbon nanotube fibers and composites exhibit a change in electrical conductivity due to strain that can be used for sensing. Some concepts for nanocomposite material sensors are presented and initial efforts to fabricate carbon nanocomposite load sensors are discussed.

  11. Percolation Threshold in Polycarbonate Nanocomposites

    NASA Astrophysics Data System (ADS)

    Ahuja, Suresh

    2014-03-01

    Nanocomposites have unique mechanical, electrical, magnetic, optical and thermal properties. Many methods could be applied to prepare polymer-inorganic nanocomposites, such as sol-gel processing, in-situ polymerization, particle in-situ formation, blending, and radiation synthesis. The analytical composite models that have been put forth include Voigt and Reuss bounds, Polymer nanocomposites offer the possibility of substantial improvements in material properties such as shear and bulk modulus, yield strength, toughness, film scratch resistance, optical properties, electrical conductivity, gas and solvent transport, with only very small amounts of nanoparticles Experimental results are compared against composite models of Hashin and Shtrikman bounds, Halpin-Tsai model, Cox model, and various Mori and Tanaka models. Examples of numerical modeling are molecular dynamics modeling and finite element modeling of reduced modulus and hardness that takes into account the modulus of the components and the effect of the interface between the hard filler and relatively soft polymer, polycarbonate. Higher nanoparticle concentration results in poor dispersion and adhesion to polymer matrix which results in lower modulus and hardness and departure from the existing composite models. As the level of silica increases beyond a threshold level, aggregates form which results in weakening of the structure. Polymer silica interface is found to be weak as silica is non-interacting promoting interfacial slip at silica-matrix junctions. Our experimental results compare favorably with those of nanocomposites of polyesters where the effect of nanoclay on composite hardness and modulus depended on dispersion of nanoclay in polyester.

  12. High performance thermoelectric nanocomposite device

    DOEpatents

    Yang, Jihui; Snyder, Dexter D.

    2011-10-25

    A thermoelectric device includes a nanocomposite material with nanowires of at least one thermoelectric material having a predetermined figure of merit, the nanowires being formed in a porous substrate having a low thermal conductivity and having an average pore diameter ranging from about 4 nm to about 300 nm.

  13. Grafting Sulfated Zirconia on Mesoporous Silica

    SciTech Connect

    Wang, Yong; Lee, Kwan Young; Choi, Saemin; Liu, Jun; Wang, Li Q.; Peden, Charles HF

    2007-06-01

    Sulfated zirconia has received considerable attention as a potential solid acid catalyst in recent years. In this paper, the preparation and properties of acid catalysts obtained by grafting ziconia with atomic precision on MCM-41 mesoporous silica were studied. TEM and potential titration characterizations revealed that ZrO2/MCM-41 with monolayer coverage can be obtained using this grafting technique. Sulfated ZrO2/MCM-41 exhibits improved thermal stability than that of bulk sulfated zirconia, as evidenced by temperature programmed characterizations and XRD analysis. Temperature programmed reaction of isopropanol was used to evaluate the acidity of sulfated ZrO2/MCM-41. It was found that the acid strength of sulfated ZrO2/MCM-41 with monolayer coverage is weaker than bulk sulfated zirconia but stronger than SiO2-Al2O3, a common strong acid catalyst.

  14. Enantioselective recognition at mesoporous chiral metal surfaces

    PubMed Central

    Wattanakit, Chularat; Côme, Yémima Bon Saint; Lapeyre, Veronique; Bopp, Philippe A.; Heim, Matthias; Yadnum, Sudarat; Nokbin, Somkiat; Warakulwit, Chompunuch; Limtrakul, Jumras; Kuhn, Alexander

    2014-01-01

    Chirality is widespread in natural systems, and artificial reproduction of chiral recognition is a major scientific challenge, especially owing to various potential applications ranging from catalysis to sensing and separation science. In this context, molecular imprinting is a well-known approach for generating materials with enantioselective properties, and it has been successfully employed using polymers. However, it is particularly difficult to synthesize chiral metal matrices by this method. Here we report the fabrication of a chirally imprinted mesoporous metal, obtained by the electrochemical reduction of platinum salts in the presence of a liquid crystal phase and chiral template molecules. The porous platinum retains a chiral character after removal of the template molecules. A matrix obtained in this way exhibits a large active surface area due to its mesoporosity, and also shows a significant discrimination between two enantiomers, when they are probed using such materials as electrodes. PMID:24548992

  15. Mesoporous titanium dioxide coating for metallic implants.

    PubMed

    Xia, Wei; Grandfield, Kathryn; Hoess, Andreas; Ballo, Ahmed; Cai, Yanling; Engqvist, Håkan

    2012-01-01

    A bioactive mesoporous titanium dioxide (MT) coating for surface drug delivery has been investigated to develop a multifunctional implant coating, offering quick bone bonding and biological stability. An evaporation induced self-assembly (EISA) method was used to prepare a mesoporous titanium dioxide coating of the anatase phase with BET surface area of 172 m(2)/g and average pore diameter of 4.3 nm. Adhesion tests using the scratch method and an in situ screw-in/screw-out technique confirm that the MT coating bonds tightly with the metallic substrate, even after removal from bone. Because of its high surface area, the bioactivity of the MT coating is much better than that of a dense TiO(2) coating of the same composition. Quick formation of hydroxyapatite (HA) in vitro can be related to enhance bonding with bone. The uptake of antibiotics by the MT coating reached 13.4 mg/cm(3) within a 24 h loading process. A sustained release behavior has been obtained with a weak initial burst. By using Cephalothin as a model drug, drug loaded MT coating exhibits a sufficient antibacterial effect on the material surface, and within millimeters from material surface, against E.coli. Additionally, the coated and drug loaded surfaces showed no cytotoxic effect on cell cultures of the osteoblastic cell line MG-63. In conclusion, this study describes a novel, biocompatiblemesoporous implant coating, which has the ability to induce HA formation and could be used as a surface drug-delivery system. PMID:21954047

  16. Single crystal particles of a mesoporous mixed transition metal oxide with a wormhole structure.

    PubMed

    Lee, B; Lu, D; Kondo, J N; Domen, K

    2001-10-21

    A new type of mesoporous mixed transition metal oxide of Nb and Ta (NbTa-TIT-1) has been prepared through a two-step calcination, which consists of single crystal particles with wormhole mesoporous structure. PMID:12240191

  17. Enhanced retention of aqueous transition metals in mesoporous silica

    NASA Astrophysics Data System (ADS)

    Nelson, J.; Bargar, J.; Brown, G. E.; Maher, K.

    2013-12-01

    Mesoporosity (2-50 nm diameter pores) is abundant within grain coatings and primary silicate minerals in natural environments. Mesopores often contribute significantly to total specific surface area and act as gateways for the transport of subsurface solutes, including nutrients and contaminants, between mineral surfaces and ambient fluids. However, the physiochemical mechanisms of sorption and transport within mesopores cannot be assumed to be the same as for macropores (>50 nm), because of confinement-induced changes in water properties, the structure of electrical double layers, solvation shells and dehydration rates of aquo ions, and the charge and reactive site densities of mineral surfaces. Despite the ubiquity of confined spaces in natural and industrial porous media, few studies have examined the molecular-scale mechanisms and geochemical reactions controlling meso-confinement phenomena in environmentally relevant materials. We conducted batch Zn sorption experiments using synthetic, controlled pore-size (i.e., 7.5-300 nm), metal-oxide beads as model geologic substrates. Comparison of Zn adsorbed onto macroporous and mesoporous silica beads indicates Zn adsorption capacity is increased in mesopores when normalized to surface area. In the presence of a background electrolyte (i.e., NaCl), Zn sorption capacity to macroporous silica is reduced; however, no significant difference in Zn sorption capacity on mesoporous silica was observed between the presence and absence of a background electrolyte. The effect of competing cations is indirect evidence that mesopores promote inner-sphere complexation and reduce outer-sphere complexation. EXAFS characterization of adsorbed zinc to macroporous silica matches that reported for low Zn coverages on silica (Roberts et al., JCIS, 2003), whereas a different spectrum is observed for the mesoporous case. Shell-by-shell fitting indicates that Zn is dominantly in octahedral coordination in macropores, as opposed to

  18. Synthesis and characterization of mesoporous semiconductors and their energy applications

    NASA Astrophysics Data System (ADS)

    Kang, Chris Byung-hwa

    In this dissertation, we examine the structure and physical properties of mesoporous group IV materials. Two different synthetic routes were developed to synthesize mesoporous germanium powder and thin film mesoporous silicon. The structural of these materials was confirmed by various analytical techniques. The electrochemical behavior of mesoporous silicon was further explored for applications as anodes in lithium ion batteries. The thermal conductivity was also measured and the electrical conductivity was tuned for potential applications as thermoelectrics. Ordered nanostructured germanium composite materials were produced using solution-phase surfactant templating methods. Anionic germanium/surfactand frameworks with a 2-D hexagonal structure were prepared and then condensed to form zero-valent porous germanium using oxidative coupling. The majority of the cationic surfactant inside the pores can be removed, resulting in mesoporous germanium with surface areas up to 500 m2/g. Thin film of mesoporous silicon was produced from polymer template porous silica films at relatively low temperature (<700 C) using magnesium vapor as reducing agent. The final porous silicon retains its ordered cubic mesoporosity. The lithium ion cycling performance of mesoporous silicon anodes was then examined. Mesoporous silicon films formed directly on a metal current collector showed stable cycling with excellent coulomb efficiency over 3000 cycles with capacities up to 3000 mAh/g at cycling rates between 1C to 20C. The results indicate porous silicon material in this size scale can accommodate the volume expansion associated with Li alloying without cracking or loosing contact with the current collector. The thermal conductivity of mesoporous silicon was also measured using the 3 omega method. Periodic pores and grain boundaries enhance phonon scattering to dissipate thermal energy throughout the material, resulting in a decrease in the thermal conductivity by 3-5 orders of magnitude

  19. Polypyrrole–titanium(IV) doped iron(III) oxide nanocomposites: Synthesis, characterization with tunable electrical and electrochemical properties

    SciTech Connect

    Nandi, Debabrata; Ghosh, Arup Kumar; Gupta, Kaushik; De, Amitabha

    2012-08-15

    Highlights: ► Synthesis and characterization of polymer nanocomposite based on titanium doped iron(III) oxide. ► Electrical conductivity increased 100 times in composite with respect to polymer. ► Electrochemical capacitance of polymer composites increased with nanooxide content. ► Thermal stability of the polymer enhanced with nano oxide content. -- Abstract: Titanium(IV)-doped synthetic nanostructured iron(III) oxide (NITO) and polypyrrole (PPy) nanocomposites was fabricated by in situ polymerization using FeCl{sub 3} as initiator. The polymer nanocomposites (PNCs) and pure NITO were characterized by X-ray diffraction, Föurier transform infrared spectroscopy, scanning electron microscopy, electron dispersive X-ray spectroscopy, transmission electron microscopy, etc. Thermo gravimetric and differential thermal analyses showed the enhancement of thermal stability of PNCs than the pure polymer. Electrical conductivity of the PNCs had increased significantly from 0.793 × 10{sup −2} S/cm to 0.450 S/cm with respect to the PPy, and that had been explained by 3-dimensional variable range hopping (VRH) conduction mechanisms. In addition, the specific capacitance of PNCs had increased from 147 F/g to 176 F/g with increasing NITO content than that of pure NITO (26 F/g), presumably due to the growing of mesoporous structure with increasing NITO content in PNCs which reduced the charge transfer resistance significantly.

  20. Thermal degradation kinetics and decomposition mechanism of PBSu nanocomposites with silica-nanotubes and strontium hydroxyapatite nanorods.

    PubMed

    Papageorgiou, D G; Roumeli, E; Chrissafis, K; Lioutas, Ch; Triantafyllidis, K; Bikiaris, D; Boccaccini, A R

    2014-03-14

    Novel poly(butylene succinate) (PBSu) nanocomposites containing 5 and 20 wt% mesoporous strontium hydroxyapatite nanorods (SrHNRs) and silica nanotubes (SiNTs) were prepared by melt-mixing. A systematic investigation of the thermal stability and decomposition kinetics of PBSu was performed using pyrolysis-gas chromatography-mass spectroscopy (Py-GC-MS) and thermogravimetry (TG). Thorough studies of evolving decomposition compounds along with the isoconversional and model-fitting analysis of mass loss data led to the proposal of a decomposition mechanism for PBSu. Moreover, the effects of SrHNRs and SiNTs on the thermal stability and decomposition kinetics of PBSu were also examined in detail. The complementary use of these techniques revealed that the incorporation of SiNTs in PBSu does not induce significant effects neither on its thermal stability nor on its decomposition mechanism. In contrast, the addition of SrHNRs resulted in the catalysis of the initial decomposition steps of PBSu and also in modified decomposition mechanisms and activation energies. The evolving gaseous products of PBSu and their evolution pattern in the SiNT nanocomposites were the same as in neat PBSu, while they were slightly modified for the SrHNR nanocomposites, confirming the findings from thermogravimetric analysis. PMID:24469599

  1. Polymer-phyllosilicate nanocomposites and their preparation

    DOEpatents

    Chaiko, David J.

    2007-01-09

    Polymer-phyllosilicate nanocomposites that exhibit superior properties compared to the polymer alone, and methods-for producing these polymer-phyllosilicate nanocomposites, are provided. Polymeric surfactant compatabilizers are adsorbed onto the surface of hydrophilic or natural phyllosilicates to facilitate the dispersal and exfoliation of the phyllosilicate in a polymer matrix. Utilizing polymeric glycol based surfactants, polymeric dicarboxylic acids, polymeric diammonium surfactants, and polymeric diamine surfactants as compatabilizers facilitates natural phyllosilicate and hydrophilic organoclay dispersal in a polymer matrix to produce nanocomposites.

  2. Superhydrophobic amorphous carbon/carbon nanotube nanocomposites

    NASA Astrophysics Data System (ADS)

    Han, Z. J.; Tay, B. K.; Shakerzadeh, M.; Ostrikov, K.

    2009-06-01

    Superhydrophobic amorphous carbon/carbon nanotube nanocomposites are fabricated by plasma immersion ion implantation with carbon nanotube forests as a template. The microstructure of the fabricated nanocomposites shows arrays of carbon nanotubes capped with amorphous carbon nanoparticles. Contact angle measurements show that both advancing and receding angles close to 180° can be achieved on the nanocomposites. The fabrication here does not require patterning of carbon nanotubes or deposition of conformal coatings with low surface energy, which are usually involved in conventional approaches for superhydrophobic surfaces. The relationship between the observed superhydrophobicity and the unique microstructure of the nanocomposites is discussed.

  3. The Synthesis of Ag-Doped Mesoporous TiO2

    SciTech Connect

    Li, Xiaohong S.; Fryxell, Glen E.; Wang, Chong M.; Engelhard, Mark H.

    2008-04-15

    Ag-doped mesoporous titanium oxide was prepared using non-ionic surfactants and easily handled titanium precursors, under mild reaction conditions. In contrast to the stabilizing effect of Cd-doping on mesoporous TiO2, Ag-doping was found to significantly destabilize the mesoporous structure.

  4. Application of ordered mesoporous carbon in solid phase microextraction for fast mass transfer and high sensitivity.

    PubMed

    Zheng, Juan; Wang, Kun; Liang, Yeru; Zhu, Fang; Wu, Dingcai; Ouyang, Gangfeng

    2016-05-21

    Due to unique high-surface-area ordered mesoporous channels interconnected with 3D network-like mesopores and π-π interactions between carbon frameworks and analytes, the as-prepared ordered mesoporous carbon-coated fiber exhibited a large adsorption amount, fast mass transport and high sensitivity. PMID:27137527

  5. Direct coating of mesoporous titania on CTAB-capped gold nanorods.

    PubMed

    Zhao, Junwei; Xu, Pengyu; Li, Yue; Wu, Jian; Xue, Junfei; Zhu, Qiannan; Lu, Xuxing; Ni, Weihai

    2016-03-14

    We demonstrate a CTAB-templated approach towards direct coating of mesoporous titania on gold nanorods in aqueous solutions. The formation of the mesoporous shell is found to be closely correlated with CTAB concentration and the amount of the titania precursor. This approach can be readily extended to form mesoporous titania shells on other CTAB-capped nanoparticles. PMID:26585611

  6. Fabrication of nanoporous nanocomposites entrapping Fe3O4 magnetic nanoparticles and oxidases for colorimetric biosensing.

    PubMed

    Kim, Moon Il; Shim, Jongmin; Li, Taihua; Lee, Jinwoo; Park, Hyun Gyu

    2011-09-12

    A nanostructured multicatalyst system consisting of Fe(3)O(4) magnetic nanoparticles (MNPs) as peroxidase mimetics and an oxidative enzyme entrapped in large-pore-sized mesoporous silica has been developed for convenient colorimetric detection of biologically important target molecules. The construction of the nanocomposites begins with the incorporation of MNPs on the walls of mesocellular silica pores by impregnating Fe(NO(3))(3)·9H(2)O, followed by the immobilization of oxidative enzymes. Glutaraldehyde crosslinking was employed to prevent enzymes leaching from the pores and led to over 20 wt% loading of the enzyme. The oxidase in the nanocomposite generates H(2)O(2) through its catalytic action for target molecules and subsequently activates MNPs to convert selected substrates into colored products. Using this strategy, two different biosensing systems were constructed employing glucose oxidase and cholesterol oxidase and their analytical capabilities were successfully verified by colorimetrically detecting the corresponding target molecules with excellent selectivity, sensitivity, reusability, and stability. Future potential applications of this technology range from biosensors to multicatalyst reactors. PMID:21837719

  7. Synthesis of MOF templated Cu/CuO@TiO2 nanocomposites for synergistic hydrogen production.

    PubMed

    Mondal, Indranil; Pal, Ujjwal

    2016-02-14

    A copper metal-organic framework (Cu-MOF) provides access to Cu/CuO@TiO2 hybrid nanocomposites with highly dispersive copper species adsorbed on a TiO2 semiconducting system. This novel nanostructure exhibits efficient hydrogen evolution performance under solar illumination of intensity ∼1 Sun. The rate of H2 production was systematically optimized under different operational parameters. Experimental observation reveals that mesoporous Cu/CuO@TiO2 nanocomposite with 0.5 wt% Cu loading showed the highest rate of H2 production (286 mmol g(-1) h(-1)), which is considerably higher than that of CuO loaded TiO2 prepared using a conventional impregnation method. This high photocatalytic H2 production activity is attributed predominantly to the presence of surface deposited Cu(0) species and the small size of the heterojunction (1-2 nm) between CuO and TiO2, which facilitate interfacial charge carrier transfer from the TiO2 nanoparticles. The catalyst showed good recyclability under prolonged exposure (30 h) to solar irradiation. Unlike many Pt decorated TiO2 photocatalysts, this hybrid photocatalyst provides an inexpensive means of harnessing solar energy. PMID:26806274

  8. Mesoporous materials used in medicine and environmental applications.

    PubMed

    Gunduz, Oguzhan; Yetmez, Mehmet; Sonmez, Maria; Georgescu, Mihai; Alexandrescu, Laura; Ficai, Anton; Ficai, Denisa; Andronescu, Ecaterina

    2015-01-01

    Mesoporous materials synthesized in the presence of templates, are commonly used for environment and medical applications. Due to the properties it holds, mesoporous silica nanoparticles is an excellent material for use in medical field, biomaterials, active principles delivery systems, enzyme immobilization and imaging. Their structure allows embedding large and small molecules, DNA adsorption and genetic transfer. Using mesoporous silica nanoparticles for delivery of bioactive molecules can protect them against degradation under physiological conditions, allow controlled drugs release and minimize side effects on healthy tissues. Cellular tests performed on mesoporous silica nanoparticles demonstrate that MSN's cytotoxicity is dependent on the size and concentration and suggests the use of larger size nanoparticles is optimal for medical applications. Mesoporous materials possess high biological compatibility, are non-toxic and can be easily modified by functionalizing the surface or inside the pores by grafting or co-condensation method. The structure, composition and pores size of this material can be optimized during synthesis by varying the stoichiometric reactants, reaction conditions, nature of the template's molecules or by functionalization method. PMID:25877095

  9. Design and functionalization of photocatalytic systems within mesoporous silica.

    PubMed

    Qian, Xufang; Fuku, Kojirou; Kuwahara, Yasutaka; Kamegawa, Takashi; Mori, Kohsuke; Yamashita, Hiromi

    2014-06-01

    In the past decades, various photocatalysts such as TiO2, transition-metal-oxide moieties within cavities and frameworks, or metal complexes have attracted considerable attention in light-excited catalytic processes. Owing to high surface areas, transparency to UV and visible light as well as easily modified surfaces, mesoporous silica-based materials have been widely used as excellent hosts for designing efficient photocatalytic systems under the background of environmental remediation and solar-energy utilization. This Minireview mainly focuses on the surface-chemistry engineering of TiO2/mesoporous silica photocatalytic systems and fabrication of binary oxides and nanocatalysts in mesoporous single-site-photocatalyst frameworks. Recently, metallic nanostructures with localized surface plasmon resonance (LSPR) have been widely studied in catalytic applications harvesting light irradiation. Accordingly, silver and gold nanostructures confined in mesoporous silica and their corresponding catalytic activity enhanced by the LSPR effect will be introduced. In addition, the integration of metal complexes within mesoporous silica materials for the construction of functional inorganic-organic supramolecular photocatalysts will be briefly described. PMID:24828540

  10. Formation of monodisperse mesoporous silica microparticles via spray-drying.

    PubMed

    Waldron, Kathryn; Wu, Winston Duo; Wu, Zhangxiong; Liu, Wenjie; Selomulya, Cordelia; Zhao, Dongyuan; Chen, Xiao Dong

    2014-03-15

    In this work, a protocol to synthesize monodisperse mesoporous silica microparticles via a unique microfluidic jet spray-drying route is reported for the first time. The microparticles demonstrated highly ordered hexagonal mesostructures with surface areas ranging from ~900 up to 1500 m(2)/g and pore volumes from ~0.6 to 0.8 cm(3)/g. The particle size could be easily controlled from ~50 to 100 μm from the same diameter nozzle via changing the initial solute content, or changing the drying temperature. The ratio of the surfactant (CTAB) and silica (TEOS), and the amount of water in the precursor were found to affect the degree of ordering of mesopores by promoting either the self-assembly of the surfactant-silica micelles or the condensation of the silica as two competing processes in evaporation induced self-assembly. The drying rate and the curvature of particles also affected the self-assembly of the mesostructure. The particle mesostructure is not influenced by the inlet drying temperature in the range of 92-160 °C, with even a relatively low temperature of 92 °C producing highly ordered mesoporous microparticles. The spray-drying derived mesoporous silica microparticles, while of larger sizes and more rapidly synthesized, showed a comparable performance with the conventional mesoporous silica MCM-41 in controlled release of a dye, Rhodamine B, indicating that these spray dried microparticles could be used for the immobilisation and controlled release of small molecules. PMID:24461839

  11. Mesoporous silica nanoparticles in target drug delivery system: A review

    PubMed Central

    Bharti, Charu; Nagaich, Upendra; Pal, Ashok Kumar; Gulati, Neha

    2015-01-01

    Due to lack of specification and solubility of drug molecules, patients have to take high doses of the drug to achieve the desired therapeutic effects for the treatment of diseases. To solve these problems, there are various drug carriers present in the pharmaceuticals, which can used to deliver therapeutic agents to the target site in the body. Mesoporous silica materials become known as a promising candidate that can overcome above problems and produce effects in a controllable and sustainable manner. In particular, mesoporous silica nanoparticles (MSNs) are widely used as a delivery reagent because silica possesses favorable chemical properties, thermal stability, and biocompatibility. The unique mesoporous structure of silica facilitates effective loading of drugs and their subsequent controlled release of the target site. The properties of mesoporous, including pore size, high drug loading, and porosity as well as the surface properties, can be altered depending on additives used to prepare MSNs. Active surface enables functionalization to changed surface properties and link therapeutic molecules. They are used as widely in the field of diagnosis, target drug delivery, bio-sensing, cellular uptake, etc., in the bio-medical field. This review aims to present the state of knowledge of silica containing mesoporous nanoparticles and specific application in various biomedical fields. PMID:26258053

  12. Oxidative nanopatterning of titanium generates mesoporous surfaces with antimicrobial properties

    PubMed Central

    Variola, Fabio; Zalzal, Sylvia Francis; Leduc, Annie; Barbeau, Jean; Nanci, Antonio

    2014-01-01

    Mesoporous surfaces generated by oxidative nanopatterning have the capacity to selectively regulate cell behavior, but their impact on microorganisms has not yet been explored. The main objective of this study was to test the effects of such surfaces on the adherence of two common bacteria and one yeast strain that are responsible for nosocomial infections in clinical settings and biomedical applications. In addition, because surface characteristics are known to affect bacterial adhesion, we further characterized the physicochemical properties of the mesoporous surfaces. Focused ion beam (FIB) was used to generate ultrathin sections for elemental analysis by energy-dispersive X-ray spectroscopy (EDS), nanobeam electron diffraction (NBED), and high-angle annular dark field (HAADF) scanning transmission electron microscopy (STEM) imaging. The adherence of Staphylococcus aureus, Escherichia coli and Candida albicans onto titanium disks with mesoporous and polished surfaces was compared. Disks with the two surfaces side-by-side were also used for direct visual comparison. Qualitative and quantitative results from this study indicate that bacterial adhesion is significantly hindered by the mesoporous surface. In addition, we provide evidence that it alters structural parameters of C. albicans that determine its invasiveness potential, suggesting that microorganisms can sense and respond to the mesoporous surface. Our findings demonstrate the efficiency of a simple chemical oxidative treatment in generating nanotextured surfaces with antimicrobial capacity with potential applications in the implant manufacturing industry and hospital setting. PMID:24872694

  13. Organized thiol functional groups in mesoporous core shell colloids

    SciTech Connect

    Marchena, Martin H.; Granada, Mara; Bordoni, Andrea V.; Joselevich, Maria; Troiani, Horacio; Williams, Federico J.; Wolosiuk, Alejandro

    2012-03-15

    The co-condensation in situ of tetraethoxysilane (TEOS) and mercaptopropyltrimethoxysilane (MPTMS) using cetyltrimethylammonium bromide (CTAB) as a template results in the synthesis of multilayered mesoporous structured SiO{sub 2} colloids with 'onion-like' chemical environments. Thiol groups were anchored to an inner selected SiO{sub 2} porous layer in a bilayered core shell particle producing different chemical regions inside the colloidal layered structure. X-Ray Photoelectron Spectroscopy (XPS) shows a preferential anchoring of the -SH groups in the double layer shell system, while porosimetry and simple chemical modifications confirm that pores are accessible. We can envision the synthesis of interesting colloidal objects with defined chemical environments with highly controlled properties. - Graphical abstract: Mesoporous core shell SiO{sub 2} colloids with organized thiol groups. Highlights: Black-Right-Pointing-Pointer Double shell mesoporous silica colloids templated with CTAB. Black-Right-Pointing-Pointer Sequential deposition of mesoporous SiO{sub 2} layers with different chemistries. Black-Right-Pointing-Pointer XPS shows the selective functionalization of mesoporous layers with thiol groups.

  14. DEVELOPMENT OF MESOPOROUS MEMBRANE MATERIALS FOR CO2 SEPARATION

    SciTech Connect

    Wei-Heng Shih; Qiang Zhao; Nanlin Wang

    2002-05-01

    Mesoporous and precipitated alumina were synthesized as the base material for CO{sub 2} adsorbent. The porous alumina is doped with Ba to enhance it CO{sub 2} affinity due to the basicity of Ba. it is shown by gas chromatograph (GC) that the addition of Ba enhances the separation CO{sub 2} from N{sub 2}. It was found that mesoporous alumina has larger specific surface area and better selectivity of CO{sub 2} than precipitated alumina. Ba improves the affinity of mesoporous alumina with CO{sub 2}. Phase may play an important role in selective adsorption of CO{sub 2}. It is speculated that mesoporous alumina is more reactive than precipitated alumina creating the xBaO {center_dot} Al{sub 2}O{sub 3} phase that may be more affinity to CO{sub 2} than N{sub 2}. On the other hand, the barium aluminate phase (Ba{sub 3}Al{sub 2}O{sub 6}) in the mesoporous sample does not help the adsorption of CO{sub 2}.

  15. Oxidative nanopatterning of titanium generates mesoporous surfaces with antimicrobial properties.

    PubMed

    Variola, Fabio; Zalzal, Sylvia Francis; Leduc, Annie; Barbeau, Jean; Nanci, Antonio

    2014-01-01

    Mesoporous surfaces generated by oxidative nanopatterning have the capacity to selectively regulate cell behavior, but their impact on microorganisms has not yet been explored. The main objective of this study was to test the effects of such surfaces on the adherence of two common bacteria and one yeast strain that are responsible for nosocomial infections in clinical settings and biomedical applications. In addition, because surface characteristics are known to affect bacterial adhesion, we further characterized the physicochemical properties of the mesoporous surfaces. Focused ion beam (FIB) was used to generate ultrathin sections for elemental analysis by energy-dispersive X-ray spectroscopy (EDS), nanobeam electron diffraction (NBED), and high-angle annular dark field (HAADF) scanning transmission electron microscopy (STEM) imaging. The adherence of Staphylococcus aureus, Escherichia coli and Candida albicans onto titanium disks with mesoporous and polished surfaces was compared. Disks with the two surfaces side-by-side were also used for direct visual comparison. Qualitative and quantitative results from this study indicate that bacterial adhesion is significantly hindered by the mesoporous surface. In addition, we provide evidence that it alters structural parameters of C. albicans that determine its invasiveness potential, suggesting that microorganisms can sense and respond to the mesoporous surface. Our findings demonstrate the efficiency of a simple chemical oxidative treatment in generating nanotextured surfaces with antimicrobial capacity with potential applications in the implant manufacturing industry and hospital setting. PMID:24872694

  16. Photocatalytic activity of a hierarchically macro/mesoporous titania.

    PubMed

    Wang, Xinchen; Yu, Jimmy C; Ho, Chunman; Hou, Yidong; Fu, Xianzhi

    2005-03-15

    Light-harvesting macroporous channels have been successfully incorporated into a mesoporous TiO(2) framework to increase its photocatalytic activity. This bimodal porous material was characterized by X-ray diffractometry in both low-angle and wide-angle ranges, N(2) adsorption-desorption analysis, scanning and transmission electron microscopy, FT-IR, and diffuse reflectance spectroscopy. Ethylene photodegradation in gas-phase medium was employed as a probe reaction to evaluate the photocatalytic reactivity of the catalysts. The results reveal that sintering temperature significantly affects the structural stability and photocatalytic activity of titania. The catalyst which calcined at 350 degrees C possessed an intact macro/mesoporous structure and showed photocatalytic reactivity about 60% higher than that of commercial P25 titania. When the sample was calcined at 500 degrees C, the macroporous structure was retained but the mesoporous structure was partly destroyed. Further heating at temperatures above 600 degrees C destroyed both macro- and mesoporous structures, accompanied by a loss in photocatalytic activity. The high photocatalytic performance of the intact macro/mesoporous TiO(2) may be explained by the existence of macrochannels that increase photoabsorption efficiency and allow efficient diffusion of gaseous molecules. PMID:15752052

  17. Multiscale modeling of polymer nanocomposites

    NASA Astrophysics Data System (ADS)

    Sheidaei, Azadeh

    In recent years, polymer nano-composites (PNCs) have increasingly gained more attention due to their improved mechanical, barrier, thermal, optical, electrical and biodegradable properties in comparison with the conventional micro-composites or pristine polymer. With a modest addition of nanoparticles (usually less than 5wt. %), PNCs offer a wide range of improvements in moduli, strength, heat resistance, biodegradability, as well as decrease in gas permeability and flammability. Although PNCs offer enormous opportunities to design novel material systems, development of an effective numerical modeling approach to predict their properties based on their complex multi-phase and multiscale structure is still at an early stage. Developing a computational framework to predict the mechanical properties of PNC is the focus of this dissertation. A computational framework has been developed to predict mechanical properties of polymer nano-composites. In chapter 1, a microstructure inspired material model has been developed based on statistical technique and this technique has been used to reconstruct the microstructure of Halloysite nanotube (HNT) polypropylene composite. This technique also has been used to reconstruct exfoliated Graphene nanoplatelet (xGnP) polymer composite. The model was able to successfully predict the material behavior obtained from experiment. Chapter 2 is the summary of the experimental work to support the numerical work. First, different processing techniques to make the polymer nanocomposites have been reviewed. Among them, melt extrusion followed by injection molding was used to manufacture high density polyethylene (HDPE)---xGnP nanocomposties. Scanning electron microscopy (SEM) also was performed to determine particle size and distribution and to examine fracture surfaces. Particle size was measured from these images and has been used for calculating the probability density function for GNPs in chapter 1. A series of nanoindentation tests have

  18. Review: nanocomposites in food packaging.

    PubMed

    Arora, Amit; Padua, G W

    2010-01-01

    The development of nanocomposites is a new strategy to improve physical properties of polymers, including mechanical strength, thermal stability, and gas barrier properties. The most promising nanoscale size fillers are montmorillonite and kaolinite clays. Graphite nanoplates are currently under study. In food packaging, a major emphasis is on the development of high barrier properties against the migration of oxygen, carbon dioxide, flavor compounds, and water vapor. Decreasing water vapor permeability is a critical issue in the development of biopolymers as sustainable packaging materials. The nanoscale plate morphology of clays and other fillers promotes the development of gas barrier properties. Several examples are cited. Challenges remain in increasing the compatibility between clays and polymers and reaching complete dispersion of nanoplates. Nanocomposites may advance the utilization of biopolymers in food packaging. PMID:20492194

  19. Colloidal QDs-polymer nanocomposites

    NASA Astrophysics Data System (ADS)

    Gordillo, H.; Suárez, I.; Rodríguez-Cantó, P.; Abargues, R.; García-Calzada, R.; Chyrvony, V.; Albert, S.; Martínez-Pastor, J.

    2012-04-01

    Nanometer-size colloidal semiconductor nanocrystals, or Quantum Dots (NQD), are very prospective active centers because their light emission is highly efficient and temperature-independent. Nanocomposites based on the incorporation of QDs inside a polymer matrix are very promising materials for application in future photonic devices because they combine the properties of QDs with the technological feasibility of polymers. In the present work some basic applications of these new materials have been studied. Firstly, the fabrication of planar and linear waveguides based on the incorporation of CdS, CdSe and CdTe in PMMA and SU-8 are demonstrated. As a result, photoluminescence (PL) of the QDs are coupled to a waveguide mode, being it able to obtain multicolor waveguiding. Secondly, nanocomposite films have been evaluated as photon energy down-shifting converters to improve the efficiency of solar cells.

  20. Probabilistic Simulation for Nanocomposite Characterization

    NASA Technical Reports Server (NTRS)

    Chamis, Christos C.; Coroneos, Rula M.

    2007-01-01

    A unique probabilistic theory is described to predict the properties of nanocomposites. The simulation is based on composite micromechanics with progressive substructuring down to a nanoscale slice of a nanofiber where all the governing equations are formulated. These equations have been programmed in a computer code. That computer code is used to simulate uniaxial strengths properties of a mononanofiber laminate. The results are presented graphically and discussed with respect to their practical significance. These results show smooth distributions.

  1. Inorganic nanofluorides and related nanocomposites

    NASA Astrophysics Data System (ADS)

    Kuznetsov, Sergei V.; Osiko, Vyacheslav V.; Tkatchenko, E. A.; Fedorov, Pavel P.

    2006-12-01

    The properties and prospects of application of fluoride nanoparticles are discussed. Pyrohydrolysis is considered as the key process determining the chemistry and technology of fluorides; its role increases on going to the nanosize region. The physical and chemical methods for the synthesis of fluoride nanoparticles, one- and two-dimensional nanoobjects as well as approaches to the preparation of nanocomposites (glass ceramics, heterovalent solid solutions with defect clusters, eutectoid composites, etc.) are analysed. Nanotechnology techniques used to produce heterogeneous nanoobjects are outlined.

  2. Silicone nanocomposite coatings for fabrics

    NASA Technical Reports Server (NTRS)

    Eberts, Kenneth (Inventor); Lee, Stein S. (Inventor); Singhal, Amit (Inventor); Ou, Runqing (Inventor)

    2011-01-01

    A silicone based coating for fabrics utilizing dual nanocomposite fillers providing enhanced mechanical and thermal properties to the silicone base. The first filler includes nanoclusters of polydimethylsiloxane (PDMS) and a metal oxide and a second filler of exfoliated clay nanoparticles. The coating is particularly suitable for inflatable fabrics used in several space, military, and consumer applications, including airbags, parachutes, rafts, boat sails, and inflatable shelters.

  3. Synthesis of continuous mesoporous alumina films with large-sized cage-type mesopores by using diblock copolymers.

    PubMed

    Jiang, Xiangfen; Suzuki, Norihiro; Bastakoti, Bishnu Prasad; Wu, Kevin C-W; Yamauchi, Yusuke

    2012-06-01

    Mesoporous alumina films with large-sized cage-type mesopores were prepared by using commercially available diblock copolymer (PS-b-PEO) and economic inorganic salt (AlCl(3)) as aluminum source. The obtained mesopore sizes drastically expand from 35 nm to 80 nm when the amount of ethanol in the precursor solutions were controlled. More interestingly, under an optimized amount of ethanol as co-solvent, there was no significant change of micelle morphology on the substrate, even though the relative amount of PS-b-PEO to alumina source was dramatically varied. When the amount of alumina precursor was decreased, the pore walls gradually became thinner, thereby improving pore connectivity. The ordered mesoporous alumina films obtained in this study exhibit high thermal stability up to 1000 °C, and their frameworks are successfully crystallized to γ-alumina phase. This technique could also be applicable for creating other metal oxide thin films with large mesopores. PMID:22556035

  4. Nanoassemblies constructed from bimodal mesoporous silica nanoparticles and surface-coated multilayer pH-responsive polymer for controlled delivery of ibuprofen.

    PubMed

    Guo, Yueyue; Sun, Jihong; Bai, Shiyang; Jin, Xiaoqi

    2016-09-01

    The pH-sensitive poly(D-A) grafted amine-functionalized bimodal mesoporous silica (D-A/BMMs) was prepared by a facile method used as a drug delivery vehicle. They exhibited superior properties such as good dispersion in aqueous medium, high drug loading efficiency, improved stability and high drug release rates. Meanwhile, its structural features and performances in a controlled delivery of ibuprofen (IBU) were systematically investigated by using XRD, N2 adsorption and desorption, SEM, TEM, FT-IR, elemental analysis and TG techniques. The results demonstrated that the obtained nanocomposite presented a flexible control over drug release by controlling the grafting amount of D-A onto the mesopores surface of aminated BMMs. The cumulative percent release of IBU from D-A/BMMs was found to be much higher at pH 7.4 than at pH 2.0. The release rate was very slow in an acidic medium but became faster in a neutral medium, owing to hydrogen bonding in an acidic medium and electrostatic repulsion between negatively charged carboxyl groups in an alkaline medium. PMID:27278781

  5. Mesoporous Silica Gel-Based Mixed Matrix Membranes for Improving Mass Transfer in Forward Osmosis: Effect of Pore Size of Filler

    NASA Astrophysics Data System (ADS)

    Lee, Jian-Yuan; Wang, Yining; Tang, Chuyang Y.; Huo, Fengwei

    2015-11-01

    The efficiency of forward osmosis (FO) process is generally limited by the internal concentration polarization (ICP) of solutes inside its porous substrate. In this study, mesoporous silica gel (SG) with nominal pore size ranging from 4-30 nm was used as fillers to prepare SG-based mixed matrix substrates. The resulting mixed matrix membranes had significantly reduced structural parameter and enhanced membrane water permeability as a result of the improved surface porosity of the substrates. An optimal filler pore size of ~9 nm was observed. This is in direct contrast to the case of thin film nanocomposite membranes, where microporous nanoparticle fillers are loaded to the membrane rejection layer and are designed in such a way that these fillers are able to retain solutes while allowing water to permeate through them. In the current study, the mesoporous fillers are designed as channels to both water and solute molecules. FO performance was enhanced at increasing filler pore size up to 9 nm due to the lower hydraulic resistance of the fillers. Nevertheless, further increasing filler pore size to 30 nm was accompanied with reduced FO efficiency, which can be attributed to the intrusion of polymer dope into the filler pores.

  6. Mesoporous Silica Gel-Based Mixed Matrix Membranes for Improving Mass Transfer in Forward Osmosis: Effect of Pore Size of Filler.

    PubMed

    Lee, Jian-Yuan; Wang, Yining; Tang, Chuyang Y; Huo, Fengwei

    2015-01-01

    The efficiency of forward osmosis (FO) process is generally limited by the internal concentration polarization (ICP) of solutes inside its porous substrate. In this study, mesoporous silica gel (SG) with nominal pore size ranging from 4-30 nm was used as fillers to prepare SG-based mixed matrix substrates. The resulting mixed matrix membranes had significantly reduced structural parameter and enhanced membrane water permeability as a result of the improved surface porosity of the substrates. An optimal filler pore size of ~9 nm was observed. This is in direct contrast to the case of thin film nanocomposite membranes, where microporous nanoparticle fillers are loaded to the membrane rejection layer and are designed in such a way that these fillers are able to retain solutes while allowing water to permeate through them. In the current study, the mesoporous fillers are designed as channels to both water and solute molecules. FO performance was enhanced at increasing filler pore size up to 9 nm due to the lower hydraulic resistance of the fillers. Nevertheless, further increasing filler pore size to 30 nm was accompanied with reduced FO efficiency, which can be attributed to the intrusion of polymer dope into the filler pores. PMID:26592565

  7. Mesoporous Silica Gel–Based Mixed Matrix Membranes for Improving Mass Transfer in Forward Osmosis: Effect of Pore Size of Filler

    PubMed Central

    Lee, Jian-Yuan; Wang, Yining; Tang, Chuyang Y.; Huo, Fengwei

    2015-01-01

    The efficiency of forward osmosis (FO) process is generally limited by the internal concentration polarization (ICP) of solutes inside its porous substrate. In this study, mesoporous silica gel (SG) with nominal pore size ranging from 4–30 nm was used as fillers to prepare SG-based mixed matrix substrates. The resulting mixed matrix membranes had significantly reduced structural parameter and enhanced membrane water permeability as a result of the improved surface porosity of the substrates. An optimal filler pore size of ~9 nm was observed. This is in direct contrast to the case of thin film nanocomposite membranes, where microporous nanoparticle fillers are loaded to the membrane rejection layer and are designed in such a way that these fillers are able to retain solutes while allowing water to permeate through them. In the current study, the mesoporous fillers are designed as channels to both water and solute molecules. FO performance was enhanced at increasing filler pore size up to 9 nm due to the lower hydraulic resistance of the fillers. Nevertheless, further increasing filler pore size to 30 nm was accompanied with reduced FO efficiency, which can be attributed to the intrusion of polymer dope into the filler pores. PMID:26592565

  8. Nanocrystal-polymer nanocomposite electrochromic device

    SciTech Connect

    Milliron, Delia; Runnerstrom, Evan; Helms, Brett; Llordes, Anna; Buonsanti, Raffaella; Garcia, Guillermo

    2015-12-08

    Described is an electrochromic nanocomposite film comprising a solid matrix of an oxide based material, the solid matrix comprising a plurality of transparent conducting oxide (TCO) nanostructures dispersed in the solid matrix and a lithium salt dispersed in the solid matrix. Also described is a near infrared nanostructured electrochromic device having a functional layer comprising the electrochromic nanocomposite film.

  9. "Green" composites and nanocomposites from soybean oil

    Technology Transfer Automated Retrieval System (TEKTRAN)

    In this study, we report preparation of epoxidized soybean oil (ESO) based "green" composites and nanocomposites. The high strength and stiffness composites and nanocomposites are formed through flax fiber and organoclay reinforcement. The epoxy resin, 1,1,1-tris(p-hydroxyphenyl)ethane triglycidyl...

  10. Graphene-based artificial nacre nanocomposites.

    PubMed

    Zhang, Yuanyuan; Gong, Shanshan; Zhang, Qi; Ming, Peng; Wan, Sijie; Peng, Jingsong; Jiang, Lei; Cheng, Qunfeng

    2016-05-01

    With its extraordinary properties as the strongest and stiffest material ever measured and the best-known electrical conductor, graphene could have promising applications in many fields, especially in the area of nanocomposites. However, processing graphene-based nanocomposites is very difficult. So far, graphene-based nanocomposites exhibit rather poor properties. Nacre, the gold standard for biomimicry, provides an excellent example and guidelines for assembling two-dimensional nanosheets into high performance nanocomposites. The inspiration from nacre overcomes the bottleneck of traditional approaches for constructing nanocomposites, such as poor dispersion, low loading, and weak interface interactions. This tutorial review summarizes recent research on graphene-based artificial nacre nanocomposites and focuses on the design of interface interactions and synergistic effects for constructing high performance nanocomposites. This tutorial review also focuses on a perspective of the dynamic area of graphene-based nanocomposites, commenting on whether the concept is viable and practical, on what has been achieved to date, and most importantly, what is likely to be achieved in the future. PMID:27039951

  11. Nanocomposite of graphene and metal oxide materials

    DOEpatents

    Liu, Jun; Aksay, Ilhan A.; Choi, Daiwon; Wang, Donghai; Yang, Zhenguo

    2015-06-30

    Nanocomposite materials comprising a metal oxide bonded to at least one graphene material. The nanocomposite materials exhibit a specific capacity of at least twice that of the metal oxide material without the graphene at a charge/discharge rate greater than about 10 C.

  12. Highly Conductive Multifunctional Graphene Polycarbonate Nanocomposites

    NASA Technical Reports Server (NTRS)

    Yoonessi, Mitra; Gaier, James R.

    2010-01-01

    Graphene nanosheet bisphenol A polycarbonate nanocomposites (0.027 2.2 vol %) prepared by both emulsion mixing and solution blending methods, followed by compression molding at 287 C, exhibited dc electrical percolation threshold of approx.0.14 and approx.0.38 vol %, respectively. The conductivities of 2.2 vol % graphene nanocomposites were 0.512 and 0.226 S/cm for emulsion and solution mixing. The 1.1 and 2.2 vol % graphene nanocomposites exhibited frequency-independent behavior. Inherent conductivity, extremely high aspect ratio, and nanostructure directed assembly of the graphene using PC nanospheres are the main factors for excellent electrical properties of the nanocomposites. Dynamic tensile moduli of nanocomposites increased with increasing graphene in the nanocomposite. The glass transition temperatures were decreased with increasing graphene for the emulsion series. High-resolution electron microscopy (HR-TEM) and small-angle neutron scattering (SANS) showed isolated graphene with no connectivity path for insulating nanocomposites and connected nanoparticles for the conductive nanocomposites. A stacked disk model was used to obtain the average particle radius, average number of graphene layers per stack, and stack spacing by simulation of the experimental SANS data. Morphology studies indicated the presence of well-dispersed graphene and small graphene stacking with infusion of polycarbonate within the stacks.

  13. Nanocomposite of graphene and metal oxide materials

    DOEpatents

    Liu, Jun; Aksay, Ilhan A.; Choi, Daiwon; Wang, Donghai; Yang, Zhenguo

    2012-09-04

    Nanocomposite materials comprising a metal oxide bonded to at least one graphene material. The nanocomposite materials exhibit a specific capacity of at least twice that of the metal oxide material without the graphene at a charge/discharge rate greater than about 10C.

  14. Nanocomposite of graphene and metal oxide materials

    DOEpatents

    Liu, Jun; Aksay, Ilhan A.; Choi, Daiwon; Wang, Donghai; Yang, Zhenguo

    2013-10-15

    Nanocomposite materials comprising a metal oxide bonded to at least one graphene material. The nanocomposite materials exhibit a specific capacity of at least twice that of the metal oxide material without the graphene at a charge/discharge rate greater than about 10 C.

  15. Highly conductive multifunctional graphene polycarbonate nanocomposites.

    PubMed

    Yoonessi, Mitra; Gaier, James R

    2010-12-28

    Graphene nanosheet-bisphenol A polycarbonate nanocomposites (0.027-2.2 vol %) prepared by both emulsion mixing and solution blending methods, followed by compression molding at 287 °C, exhibited dc electrical percolation threshold of ∼0.14 and ∼0.38 vol %, respectively. The conductivities of 2.2 vol % graphene nanocomposites were 0.512 and 0.226 S/cm for emulsion and solution mixing. The 1.1 and 2.2 vol % graphene nanocomposites exhibited frequency-independent behavior. Inherent conductivity, extremely high aspect ratio, and nanostructure directed assembly of the graphene using PC nanospheres are the main factors for excellent electrical properties of the nanocomposites. Dynamic tensile moduli of nanocomposites increased with increasing graphene in the nanocomposite. The glass transition temperatures were decreased with increasing graphene for the emulsion series. High-resolution electron microscopy (HR-TEM) and small-angle neutron scattering (SANS) showed isolated graphene with no connectivity path for insulating nanocomposites and connected nanoparticles for the conductive nanocomposites. A stacked disk model was used to obtain the average particle radius, average number of graphene layers per stack, and stack spacing by simulation of the experimental SANS data. Morphology studies indicated the presence of well-dispersed graphene and small graphene stacking with infusion of polycarbonate within the stacks. PMID:21082818

  16. Actinide sequestration using self-assembled monolayers on mesoporous supports.

    PubMed

    Fryxell, Glen E; Lin, Yuehe; Fiskum, Sandy; Birnbaum, Jerome C; Wu, Hong; Kemner, Ken; Kelly, Shelley

    2005-03-01

    Surfactant templated synthesis of mesoporous ceramics provides a versatile foundation upon which to create high efficiency environmental sorbents. These nanoporous ceramic oxides condense a huge amount of surface area into a very small volume. The ceramic oxide interface is receptive to surface functionalization through molecular self-assembly. The marriage of mesoporous ceramics with self-assembled monolayer chemistry creates a powerful new class of environmental sorbent materials called self-assembled monolayers on mesoporous supports (SAMMS). These SAMMS materials are highly efficient sorbents whose interfacial chemistry can be fine-tuned to selectively sequester a specific target species, such as heavy metals, tetrahedral oxometalate anions, and radionuclides. Details addressing the design, synthesis, and characterization of SAMMS materials specifically designed to sequester actinides, of central importance to the environmental cleanup necessary after 40 years of weapons-grade plutonium production, as well as evaluation of their binding affinities and kinetics are presented. PMID:15787373

  17. Mesoporous materials for energy conversion and storage devices

    NASA Astrophysics Data System (ADS)

    Li, Wei; Liu, Jun; Zhao, Dongyuan

    2016-06-01

    To meet the growing energy demands in a low-carbon economy, the development of new materials that improve the efficiency of energy conversion and storage systems is essential. Mesoporous materials offer opportunities in energy conversion and storage applications owing to their extraordinarily high surface areas and large pore volumes. These properties may improve the performance of materials in terms of energy and power density, lifetime and stability. In this Review, we summarize the primary methods for preparing mesoporous materials and discuss their applications as electrodes and/or catalysts in solar cells, solar fuel production, rechargeable batteries, supercapacitors and fuel cells. Finally, we outline the research and development challenges of mesoporous materials that need to be overcome to increase their contribution in renewable energy applications.

  18. Syntheses and applications of periodic mesoporous organosilica nanoparticles.

    PubMed

    Croissant, Jonas G; Cattoën, Xavier; Wong, Michel Chi Man; Durand, Jean-Olivier; Khashab, Niveen M

    2015-12-28

    Periodic Mesoporous Organosilica (PMO) nanomaterials are envisioned to be one of the most prolific subjects of research in the next decade. Similar to mesoporous silica nanoparticles (MSN), PMO nanoparticles (NPs) prepared from organo-bridged alkoxysilanes have tunable mesopores that could be utilized for many applications such as gas and molecule adsorption, catalysis, drug and gene delivery, electronics, and sensing; but unlike MSN, the diversity in chemical nature of the pore walls of such nanomaterials is theoretically unlimited. Thus, we expect that PMO NPs will attract considerable interest over the next decade. In this review, we will present a comprehensive overview of the synthetic strategies for the preparation of nanoscaled PMO materials, and then describe their applications in catalysis and nanomedicine. The remarkable assets of the PMO structure are also detailed, and insights are provided for the preparation of more complex PMO nanoplatforms. PMID:26585498

  19. Selective SERS Sensing Modulated by Functionalized Mesoporous Films.

    PubMed

    López-Puente, Vanesa; Angelomé, Paula C; Soler-Illia, Galo J A A; Liz-Marzán, Luis M

    2015-11-25

    A hybrid material comprising metal nanoparticles embedded in functionalized mesoporous thin films was constructed, and its use as a selective SERS-based sensor was demonstrated. The presence of specific functional groups in the pore network allows control over the surface chemistry of the pores, tuning the selectivity for specific molecules. Amino-functionalized hybrid mesoporous thin films were used in a proof of concept experiment, to discern the presence of methylene blue (MB) in mixtures with acid blue (AB), with no need for any sample pretreatment step. Selective detection of MB was possible through entrapment of AB in the mesoporous matrix, based on its high affinity for amino groups. The sensor selectivity can be tuned by varying the solution pH, rendering a pH responsive surface and thus, selective SERS-based sensing. The developed sensors allow specific detection of molecules in complex matrixes. PMID:26536368

  20. Syntheses and applications of periodic mesoporous organosilica nanoparticles

    NASA Astrophysics Data System (ADS)

    Croissant, Jonas G.; Cattoën, Xavier; Wong Chi Man, Michel; Durand, Jean-Olivier; Khashab, Niveen M.

    2015-12-01

    Periodic Mesoporous Organosilica (PMO) nanomaterials are envisioned to be one of the most prolific subjects of research in the next decade. Similar to mesoporous silica nanoparticles (MSN), PMO nanoparticles (NPs) prepared from organo-bridged alkoxysilanes have tunable mesopores that could be utilized for many applications such as gas and molecule adsorption, catalysis, drug and gene delivery, electronics, and sensing; but unlike MSN, the diversity in chemical nature of the pore walls of such nanomaterials is theoretically unlimited. Thus, we expect that PMO NPs will attract considerable interest over the next decade. In this review, we will present a comprehensive overview of the synthetic strategies for the preparation of nanoscaled PMO materials, and then describe their applications in catalysis and nanomedicine. The remarkable assets of the PMO structure are also detailed, and insights are provided for the preparation of more complex PMO nanoplatforms.

  1. Plutonium complexation by phosphonate-functionalized mesoporous silica

    SciTech Connect

    Parsons-Moss, T; Schwaiger, L K; Hubaud, A; Hu, Y J; Tuysuz, H; Yang, P; Balasubramanian, K; Nitsche, H

    2010-10-27

    MCM-41-type mesoporous silica functionalized with the CMPO-based 'Ac-Phos' silane has been reported in the literature (1) to show good capacity as an acftinide sorbent material, with potential applications in environmental sequestration, aqueous waste separation and/or vitrification, and chemical sensing of actinides in solution. The study explores the complexation of Pu(IV and VI) and other selected actinides and lanthanides by SBA-15 type mesoporous silica functionalized with Ac-Phos. The Pu binding kinetics and binding capacity were determined for both the Ac-Phos functionalized and unmodified SBA-15. They analyzed the binding geometry and redox behavior of Pu(VI) by X-ray absorption spectroscopy (XAS). They discuss the synthesis and characterization of the functionalized mesoporous material, batch sorption experiments, and the detailed analyses of the actinide complexes that are formed. Structural measurements are paired with high-level quantum mechanical modeling to elucidate the binding mechanisms.

  2. Adsorption of vitamin E on mesoporous titania nanocrystals

    SciTech Connect

    Shih, C.J.; Lin, C.T.; Wu, S.M.

    2010-07-15

    Tri-block nonionic surfactant and titanium chloride were used as starting materials for the synthesis of mesoporous titania nanocrystallite powders. The main objective of the present study was to examine the synthesis of mesoporous titania nanocrystals and the adsorption of vitamin E on those nanocrystals using X-ray diffraction (XRD), transmission electron microscopy, and nitrogen adsorption and desorption isotherms. When the calcination temperature was increased to 300 {sup o}C, the reflection peaks in the XRD pattern indicated the presence of an anatase phase. The crystallinity of the nanocrystallites increased from 80% to 98.6% with increasing calcination temperature from 465 {sup o}C to 500 {sup o}C. The N{sub 2} adsorption data and XRD data taken after vitamin E adsorption revealed that the vitamin E molecules were adsorbed in the mesopores of the titania nanocrystals.

  3. Actinide Sequestration Using Self-Assembled Monolayers on Mesoporous Supports

    SciTech Connect

    Fryxell, Glen E.; Lin, Yuehe; Fiskum, Sandra K.; Birnbaum, Jerome C.; Wu, Hong; Kemner, K. M.; Kelly, Shelley

    2005-03-01

    Surfactant templated synthesis of mesoporous ceramics provides a versatile foundation upon which to create high efficiency environmental sorbents. These nanoporous ceramic oxides condense a huge amount of surface area into a very small volume. The ceramic oxide interface is receptive to surface functionalization through molecular self-assembly. The marriage of mesoporous ceramics with self-assembled monolayer chemistry creates a powerful new class of environmental sorbent materials called self-assembled monolayers on mesoporous supports (SAMMS). These SAMMS materials are highly efficient sorbents, whose interfacial chemistry can be fine-tuned to selectively sequester a specific target species, such as heavy metals, tetrahedral oxometallate anions and radionuclides. Details addressing the design, synthesis and characterization of SAMMS materials specifically designed to sequester actinides, of central importance to the environmental clean-up necessary after 40 years of weapons grade plutonium production, as well as evaluation of their binding affinities and kinetics are presented.

  4. Mesoporous materials for clean energy technologies.

    PubMed

    Linares, Noemi; Silvestre-Albero, Ana M; Serrano, Elena; Silvestre-Albero, Joaquín; García-Martínez, Javier

    2014-11-21

    Alternative energy technologies are greatly hindered by significant limitations in materials science. From low activity to poor stability, and from mineral scarcity to high cost, the current materials are not able to cope with the significant challenges of clean energy technologies. However, recent advances in the preparation of nanomaterials, porous solids, and nanostructured solids are providing hope in the race for a better, cleaner energy production. The present contribution critically reviews the development and role of mesoporosity in a wide range of technologies, as this provides for critical improvements in accessibility, the dispersion of the active phase and a higher surface area. Relevant examples of the development of mesoporosity by a wide range of techniques are provided, including the preparation of hierarchical structures with pore systems in different scale ranges. Mesoporosity plays a significant role in catalysis, especially in the most challenging processes where bulky molecules, like those obtained from biomass or highly unreactive species, such as CO2 should be transformed into most valuable products. Furthermore, mesoporous materials also play a significant role as electrodes in fuel and solar cells and in thermoelectric devices, technologies which are benefiting from improved accessibility and a better dispersion of materials with controlled porosity. PMID:24699503

  5. Zirconia-silica based mesoporous desulfurization adsorbents

    NASA Astrophysics Data System (ADS)

    Palomino, Jessica M.; Tran, Dat T.; Kareh, Ana R.; Miller, Christopher A.; Gardner, Joshua M. V.; Dong, Hong; Oliver, Scott R. J.

    2015-03-01

    We report a series of mesoporous silicate sorbent materials templated by long-chain primary alkylamines that display record level of desulfurization of the jet fuel JP-8. Pure silica frameworks and those with a Si:Zr synthesis molar ratio ranging from 44:1 to 11:1 were investigated. The optimum sorbent was identified as dodecylamine-templated silica-zirconia synthesized from a gel with Si:Zr molar ratio of 15:1. With an optimized silver loading of 11 wt.%, a saturation adsorption capacity of 39.4 mgS g-1 and a silver efficiency of 1.21 molS mol Ag-1 were observed for JP-8. This sorbent displayed exceptional regenerability, maintaining 86% of its initial capacity in model fuel after solvent regeneration with diethyl ether. Low-cost, portable and reusable sorbents for the desulfurization of JP-8 jet fuel are needed to make solid oxide fuel cells (SOFCs) a reality for military power needs. SOFCs require ultra-low sulfur content fuel, which traditional desulfurization methods cannot achieve.

  6. Enzyme-Powered Hollow Mesoporous Janus Nanomotors.

    PubMed

    Ma, Xing; Jannasch, Anita; Albrecht, Urban-Raphael; Hahn, Kersten; Miguel-López, Albert; Schäffer, Erik; Sánchez, Samuel

    2015-10-14

    The development of synthetic nanomotors for technological applications in particular for life science and nanomedicine is a key focus of current basic research. However, it has been challenging to make active nanosystems based on biocompatible materials consuming nontoxic fuels for providing self-propulsion. Here, we fabricate self-propelled Janus nanomotors based on hollow mesoporous silica nanoparticles (HMSNPs), which are powered by biocatalytic reactions of three different enzymes: catalase, urease, and glucose oxidase (GOx). The active motion is characterized by a mean-square displacement (MSD) analysis of optical video recordings and confirmed by dynamic light scattering (DLS) measurements. We found that the apparent diffusion coefficient was enhanced by up to 83%. In addition, using optical tweezers, we directly measured a holding force of 64 ± 16 fN, which was necessary to counteract the effective self-propulsion force generated by a single nanomotor. The successful demonstration of biocompatible enzyme-powered active nanomotors using biologically benign fuels has a great potential for future biomedical applications. PMID:26437378

  7. Novel mesoporous P-doped graphitic carbon nitride nanosheets coupled with ZnIn2S4 nanosheets as efficient visible light driven heterostructures with remarkably enhanced photo-reduction activity

    NASA Astrophysics Data System (ADS)

    Chen, Wei; Liu, Tian-Yu; Huang, Ting; Liu, Xiao-Heng; Yang, Xu-Jie

    2016-02-01

    In this report, we rationally designed and fabricated P-C3N4/ZnIn2S4 nanocomposites by in situ immobilizing ZnIn2S4 nanosheets onto the surface of mesoporous P-doped graphite carbon nitrogen (P-C3N4) nanosheets in a mixed solvothermal environment; their application to the photoreduction of 4-nitroaniline was used to estimate the photocatalytic performance. Different to the template route, here the mesoporous P-C3N4 nanosheets were prepared with a template-free strategy. The as-fabricated P-C3N4/ZnIn2S4 nanocomposites were systematically characterized by analyzing the phase structure, chemical components, electronic and optical properties and separation of charge carrier pairs. More importantly, these P-C3N4/ZnIn2S4 heterostructures have been proven to be highly efficient visible light responsive photocatalysts for photo-reduction, and meanwhile exhibit excellent photo-stability during recycling runs. The sufficient evidence reveals that the significantly improved photocatalytic performance is mainly attributed to the more efficient charge carrier separation based on the construction of a close heterogeneous interface. This work may provide new insights into the utilization of P-C3N4/ZnIn2S4 nanocomposites as visible light driven photocatalysts for comprehensive organic transformations in the field of fine chemical engineering.In this report, we rationally designed and fabricated P-C3N4/ZnIn2S4 nanocomposites by in situ immobilizing ZnIn2S4 nanosheets onto the surface of mesoporous P-doped graphite carbon nitrogen (P-C3N4) nanosheets in a mixed solvothermal environment; their application to the photoreduction of 4-nitroaniline was used to estimate the photocatalytic performance. Different to the template route, here the mesoporous P-C3N4 nanosheets were prepared with a template-free strategy. The as-fabricated P-C3N4/ZnIn2S4 nanocomposites were systematically characterized by analyzing the phase structure, chemical components, electronic and optical properties and

  8. Nanoclay-based hierarchical interconnected mesoporous CNT/PPy electrode with improved specific capacitance for high performance supercapacitors.

    PubMed

    Oraon, Ramesh; De Adhikari, Amrita; Tiwari, Santosh Kumar; Nayak, Ganesh Chandra

    2016-05-31

    A natural layered clay known as montmorillonite, a lamellar aluminosilicate with ∼1 nm thickness, has attracted intense attention in ongoing research due to its large natural abundance and environmental friendliness. Endowed with highly active surface sites the nanoclay has been extensively used in various fields viz. catalysis, biosensors etc. even though the role played by nanoclay on energy storage performance has not been elucidated. In this present work, a series of nanoclay (Closite 30B) based hierarchical open interconnected mesoporous electrode materials for supercapacitors (SCs) has been synthesized in the presence of carbon nanotubes (CNTs) and polypyrrole (PPy) by a facile in situ and ex situ approach. The role of nanoclay was explored as a dopant and its substantial doping effect exerted on the electrochemical performance towards energy storage was investigated. A coating of PPy over CNTs and nanoclay was confirmed from FESEM analysis which revealed the genesis of a nanoclay-supported hierarchical interconnected mesoporous framework. Furthermore, a PPy-coated CNT array in the presence of nanoclay was found to be highly porous with a high specific surface area without obvious deterioration. These interconnected structures can contribute to better penetration of electrolyte ions by shortening the path length for rapid transport of ions and electrons even at high rates. Cyclic voltammetry measurements revealed that nanoclay based in situ composite (CNP) and ex situ composite (CPN) exhibited a maximum specific capacitance of 425 F g(-1) and 317 F g(-1), respectively at a scan rate of 10 mV s(-1), which is comparatively higher than that of CP (i.e. PPy-coated CNTs) (76.77 F g(-1)). Similarly, a 273% increase in the specific capacitance of PPy was achieved after nanoclay incorporation in the nanocomposite NP (i.e. PPy-coated nanoclay) as compared to virgin PPy. These results are in good agreement with the specific capacitance performance by galvanostatic

  9. Lower Permittivity Characteristic of Mesoporous-Alumina/Epoxy Composite due to Particle Porosity

    NASA Astrophysics Data System (ADS)

    Kurimoto, Muneaki; Murakami, Yoshinobu; Nagao, Masayuki

    Introduction of metal oxide nanoparticles to polymer composite material is known to have unique dielectric behavior and significant advantage in the electrical insulation performance of electrical power apparatus. This paper presents an attempt to derive the dielectric characteristics of polymer composite filled with the metal oxide particle which has mesoporous structure. Experiments were carried out in the epoxy composites filled with alumina microparticles which have the mesoporous structure (mesoporous-alumina/epoxy composites) with different particle content. Based on the measurement of the specific gravity of mesoporous-alumina/epoxy composites, the porosity of mesoporous-alumina particle in the epoxy matrix was found to be higher than that of nonporous-alumina particle. Furthermore, we evaluated relative permittivity of mesoporous-alumina/epoxy composites by measuring the capacitance of its specimens. As the results, we verified that the permittivity of mesoporous-alumina/epoxy composites was lower than that of nonporous-alumina/epoxy composites due to the particle porosity.

  10. The synthesis and application of two mesoporous silica nanoparticles as drug delivery system with different shape

    NASA Astrophysics Data System (ADS)

    Wang, Jiayi; Wang, Zhuyuan; Chen, Hui; Zong, Shenfei; Cui, Yiping

    2015-05-01

    Mesoporous silica nanospheres(MSNSs) have been obtained utilizing the conventional reverse micelles synthesis method while the mesoporous silica nanorods(MSNRs) have been acquired by means of changing certain parameters. Afterwards, the prepared mesoporous silica nanospheres and nanorods were used as drug carriers to load and release the classical cancer therapeutic drug—DOX. According to the absorption spectra, the encapsulation efficiency of the mesoporous silica nanospheres is almost as high as that of the nanospheres. Different from the familiar encapsulation efficiency, the release characteristic curves of the mesoporous silica nanospheres and nanorods possessed certain differences during the release process. Finally incellular fluorescence imaging was achieved to observe the endocytosis of the mesoporous silica materials. Our results show that although both of the two kinds of nanoparticles possess favourable properties for loading and releasing drugs, the mesoporous silica nanospheres perform better in dispersity and controlled release than the nanorods, which probably endow them the potential as incellular drug delivery system.

  11. Advances in rubber/halloysite nanotubes nanocomposites.

    PubMed

    Jia, Zhixin; Guo, Baochun; Jia, Demin

    2014-02-01

    The research advances in rubber/halloysite nanotubes (rubber/HNTs) nanocomposites are reviewed. HNTs are environmentally-friendly natural nanomaterials, which could be used to prepare the rubber-based nanocomposites with high performance and low cost. Unmodified HNTs could be adopted to prepare the rubber/HNTs composites with improved mechanical properties, however, the rubber/HNTs nanocomposites with fine morphology and excellent properties were chiefly prepared with various modifiers by in situ mixing method. A series of rubber/HNTs nanocomposites containing several rubbers (SBR, NR, xSBR, NBR, PU) and different modifiers (ENR, RH, Si69, SA, MAA, ILs) have been investigated. The results showed that all the rubber/HNTs nanocomposites achieved strong interfacial interaction via interfacial covalent bonds, hydrogen bonds or multiple interactions, realized significantly improved dispersion of HNTs at nanoscale and exhibited excellent mechanical performances and other properties. PMID:24749454

  12. Dynamic Strength Ceramic Nanocomposites Under Pulse Loading

    NASA Astrophysics Data System (ADS)

    Skripnyak, Evgeniya G.; Skripnyak, Vladimir V.; Vaganova, Irina K.; Skripnyak, Vladimir A.

    2015-06-01

    Multi-scale computer simulation approach has been applied to research of strength of nanocomposites under dynamic loading. The influence of mesoscopic substructures on the dynamic strength of ceramic and hybrid nanocomposites, which can be formed using additive manufacturing were numerically investigated. At weak shock wave loadings the shear strength and the spall strength of ceramic and hybrid nanocomposites depends not only phase concentration and porosity, but size parameters of skeleton substructures. The influence of skeleton parameter on the shear strength and the spall strength of ceramic nanocomposites with the same concentration of phases decreases with increasing amplitude of the shock pulse of microsecond duration above the double amplitude of the Hugoniot elastic limit of nanocomposites. This research carried out in 2014 -2015 was supported by grant from The Tomsk State University Academic D.I. Mendeleev Fund Program and also Ministry of Sciences and Education of Russian Federation (State task 2014/223, project 1943, Agreement 14.132.

  13. Optical and electronic loss analysis of mesoporous solar cells

    NASA Astrophysics Data System (ADS)

    Kovalsky, Anton; Burda, Clemens

    2016-07-01

    We review the art of complete optical and electronic characterization of the popular mesoporous solar cell motif. An overview is given of how the mesoporous paradigm is applied to solar cell technology, followed by a discussion on the variety of techniques available for thoroughly probing efficiency leaching mechanisms at every stage of the energy transfer pathway. Some attention is dedicated to the rising importance of computational results to augment loss analysis due to the complexity of solar cell devices, which have emergent properties that are important to account for, but difficult to measure, such as parasitic absorption.

  14. Container effect in nanocasting synthesis of mesoporous metal oxides.

    PubMed

    Sun, Xiaohong; Shi, Yifeng; Zhang, Peng; Zheng, Chunming; Zheng, Xinyue; Zhang, Fan; Zhang, Yichi; Guan, Naijia; Zhao, Dongyuan; Stucky, Galen D

    2011-09-21

    We report a general reaction container effect in the nanocasting synthesis of mesoporous metal oxides. The size and shape of the container body in conjunction with simply modifying the container opening accessibility can be used to control the escape rate of water and other gas-phase byproducts in the calcination process, and subsequently affect the nanocrystal growth of the materials inside the mesopore space of the template. In this way, the particle size, mesostructure ordering, and crystallinity of the final product can be systemically controlled. The container effect also explain some of the problems with reproducibility in previously reported results. PMID:21861449

  15. Hypercrosslinked Phenolic Polymers with Well Developed Mesoporous Frameworks

    SciTech Connect

    Mahurin, Shannon Mark; Dai, Sheng

    2015-01-01

    A soft chemistry synthetic strategy based on a Friedel Crafts alkylation reaction is developed for the textural engineering of phenolic resin (PR) with a robust mesoporous framework to avoid serious framework shrinkage and maximize retention of organic functional moieties. By taking advantage of the structural benefits of molecular bridges, the resultant sample maintains a bimodal micro-mesoporous architecture with well-preserved organic functional groups, which is effective for carbon capture. Moreover, this soft chemistry synthetic protocol can be further extended to nanotexture other aromatic-based polymers with robust frameworks.

  16. Monolithic Gyroidal Mesoporous Mixed Titanium–Niobium Nitrides

    PubMed Central

    2015-01-01

    Mesoporous transition metal nitrides are interesting materials for energy conversion and storage applications due to their conductivity and durability. We present ordered mixed titanium–niobium (8:2, 1:1) nitrides with gyroidal network structures synthesized from triblock terpolymer structure-directed mixed oxides. The materials retain both macroscopic integrity and mesoscale ordering despite heat treatment up to 600 °C, without a rigid carbon framework as a support. Furthermore, the gyroidal lattice parameters were varied by changing polymer molar mass. This synthesis strategy may prove useful in generating a variety of monolithic ordered mesoporous mixed oxides and nitrides for electrode and catalyst materials. PMID:25122534

  17. Hypercrosslinked phenolic polymers with well developed mesoporous frameworks

    DOE PAGESBeta

    Zhang, Jinshui; Qiao, Zhenan -An; Mahurin, Shannon Mark; Jiang, Xueguang; Chai, Song -Hai; Lu, Hanfeng; Nelson, Kimberly M.; Dai, Sheng

    2015-02-12

    A soft chemistry synthetic strategy based on a Friedel Crafts alkylation reaction is developed for the textural engineering of phenolic resin (PR) with a robust mesoporous framework to avoid serious framework shrinkage and maximize retention of organic functional moieties. By taking advantage of the structural benefits of molecular bridges, the resultant sample maintains a bimodal micro-mesoporous architecture with well-preserved organic functional groups, which is effective for carbon capture. Furthermore, this soft chemistry synthetic protocol can be further extended to nanotexture other aromatic-based polymers with robust frameworks.

  18. Phase State and Dynamics of Fluids in Mesoporous Solids

    NASA Astrophysics Data System (ADS)

    Valiullin, Rustem

    2011-03-01

    Fundamental understanding of the correlations between the phase state and dynamics of fluids confined to mesoporous solids is an important prerequisite for their optimal use in practical applications. The present contribution describes some recent progress in the exploration of such interrelations using nuclear magnetic resonance. In particular, transport properties of fluids during gas-liquid, solid-liquid and liquid-liquid transitions occurring in pore spaces of mesoporous solids are discussed and are shown to bear strong correlations. From the results presented it will, in particular, become evident that molecular diffusivity is a sensitive microscopic parameter not only to the thermodynamic state of the system, but also the history of its preparation.

  19. Diffusion NMR of Fluids Confined to Mesopores under High Pressures

    NASA Astrophysics Data System (ADS)

    Zeigermann, Philipp; Dvoyashkin, Muslim; Gläser, Roger; Valiullin, Rustem

    2011-03-01

    Supercritical fluids are extensively used in various chemical applications including processes involving porous solids. The knowledge of their transport in bulk as well as under spatial confinements is critical for modeling and optimizing chemical reactions. In this contribution, we describe a high-pressure cell designed for pulsed field gradient NMR studies of diffusion of supercritical solvents in mesoporous materials. Some preliminary results on diffusion properties of ethane in bulk phase and confined to pores of mesoporous silicon obtained in a broad range of pressures below and above the critical temperature are reported.

  20. Container Effect in Nanocasting Synthesis of Mesoporous Metal Oxides

    SciTech Connect

    Sun, Xiaohong; Shi, Yifeng; Zhang, Peng; Zheng, Chunming; Zheng, Xinyue; Zhang, Fan; Zhang, Yichi; Guan, Naijia; Zhao, Dongyuan; Stucky, Galen D.

    2011-08-23

    We report a general reaction container effect in the nanocasting synthesis of mesoporous metal oxides. The size and shape of the container body in conjunction with simply modifying the container opening accessibility can be used to control the escape rate of water and other gas-phase byproducts in the calcination process, and subsequently affect the nanocrystal growth of the materials inside the mesopore space of the template. In this way, the particle size, mesostructure ordering, and crystallinity of the final product can be systemically controlled. The container effect also explain some of the problems with reproducibility in previously reported results.

  1. Encapsulating magnetic and fluorescent mesoporous silica into thermosensitive chitosan microspheres for cell imaging and controlled drug release in vitro.

    PubMed

    Gui, Rijun; Wang, Yanfeng; Sun, Jie

    2014-01-01

    In this study, for the first time, multifunctional inorganic/organic core/shell hybrid microspheres consisted of Fe3O4 nanoparticles/CdTe quantum dots dual-embedded mesoporous silica nanocomposites (MQ-MSN) as cores and P(N-isopropylacrylamide)-graft-Chitosan microgels (PNIPAM-g-CS) as shells were prepared by copolymerization of NIPAM and CS in the presence of MQ-MSN. The preparation of microspheres (i.e., MQ-MSN/PNIPAM-g-CS) included three stages. First, Fe3O4/CdTe nanocomposites (MQ NCs) were prepared by self-assembly of electrostatic adsorption. Second, MQ NCs were encapsulated into silica spheres by modified Stöber method to obtain MQ-MSN. Third, NIPAM monomers were initiated to fabricate PNIPAM networks with MQ-MSN distributed below the lower critical solution temperature (LCST) of PNIPAM, and then PNIPAM reacted with CS to form PNIPAM-g-CS copolymers above the LCST, meanwhile the PNIPAM networks collapsed to form microspheres, resulting in the MQ-MSN encapsulated into microspheres. The microspheres were systematically characterized, displaying perfect magnetic/fluorescent properties and thermo-sensitivity. HepG2 cancer cells treated with the microspheres revealed bright fluorescence imaging. Both the efficiency and capacity of Adriamycin (ADM) loaded into the microspheres were gradually increased with ADM concentration increasing. The ADM cumulative release in vitro from ADM-loaded microspheres was significant at a higher temperature (or a lower pH). The released ADM still maintained high anticancer activity, and the blank microsphere carriers hardly produced toxicity to HepG2 cells. Hence, the multifunctional microspheres exhibited a promising application especially as thermo/pH-sensitive drug carriers for in vivo therapy. PMID:24060924

  2. Volume 1, 1st Edition, Multiscale Tailoring of Highly Active and Stable Nanocomposite Catalysts, Final Technical Report

    SciTech Connect

    Veser, Goetz

    2009-08-31

    wealth of literature on the formation of mesoporous silica materials motivated investigations of nanocomposite silica catalysts. High surface area silicas are synthesized via sol-gel methods, and the addition of metal-salts lead to the formation of stable nanocomposite Ni- and Fe- silicates. The results of these investigations have increased the fundamental understanding and improved the applicability of nanocatalysts for clean energy applications.

  3. MAGNETIC IMAGING OF NANOCOMPOSITE MAGNETS

    SciTech Connect

    VOLKOV,V.V.ZHU,Y.

    2003-08-03

    Understanding the structure and magnetic behavior is crucial for optimization of nanocomposite magnets with high magnetic energy products. Many contributing factors such as phase composition, grain size distribution and specific domain configurations reflect a fine balance of magnetic energies at nanometer scale. For instance, magnetocrystalline anisotropy of grains and their orientations, degree of exchange coupling of magnetically soft and hard phases and specific energy of domain walls in a material. Modern microscopy, including Lorentz microscopy, is powerful tool for visualization and microstructure studies of nanocomposite magnets. However, direct interpretation of magnetically sensitive Fresnel/Foucault images for nanomagnets is usually problematic, if not impossible, because of the complex image contrast due to small grain size and sophisticated domain structure. Recently we developed an imaging technique based on Lorentz phase microscopy [l-4], which allows bypassing many of these problems and get quantitative information through magnetic flux mapping at nanometer scale resolution with a magnetically calibrated TEM [5]. This is our first report on application of this technique to nanocomposite magnets. In the present study we examine a nanocomposite magnet of nominal composition Nd{sub 2}Fe{sub 14+{delta}}B{sub 1.45} (14+{delta}=23.3, i.e. ''hard'' Nd{sub 2}Fe{sub 14}B-phase and 47.8 wt% of ''soft'' {alpha}-Fe phase ({delta}=9.3)), produced by Magnequench International, Inc. Conventional TEM/HREM study (Fig. 1-2) suggests that material has a bimodal grain-size distribution with maximum at d{sub max}=25 nm for Nd{sub 2}Fe{sub 14}B phase and d{sub max} = 15 nm for {alpha}-Fe phase (Fig.1c, Fig.2) in agreement with synchrotron X-ray studies (d{sub max}=23.5 nm for Nd{sub 2}Fe{sub 14}B [6]). Lattice parameters for Nd{sub 2}Fe{sub 14}B phase are a=8.80 and c=12.2 {angstrom}, as derived from SAED ring patterns (Fig.1a), again in good agreement with X-ray data

  4. Adsorption of mycotoxins in beverages onto functionalized mesoporous silicas

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Mycotoxins, natural toxins produced by fungi, are a global concern as contaminates of agricultural commodities. Exposure to these toxins can be reduced by the use of binding materials. Templated mesoporous silicas are promising materials with favorable adsorptive properties for dyes, ions, and toxin...

  5. Contamination-resistant silica antireflective coating with closed ordered mesopores.

    PubMed

    Sun, Jinghua; Zhang, Qinghua; Ding, Ruimin; Lv, Haibing; Yan, Hongwei; Yuan, Xiaodong; Xu, Yao

    2014-08-21

    Porous silica optical antireflective (AR) coatings prepared by traditional sol-gel method have been extensively used for high power laser systems, but a serious drawback is that contamination existing in the high vacuum is easily absorbed by the disordered open pore structure, resulting in a fast decrease in transmittance. To improve the stability of transmittance in vacuum, a contamination-resistant silica AR coating with ordered mesopores completely closed by hydrophobic-oleophobic groups was successfully developed on a fused quartz substrate. The ordered mesopores in the coating were controlled under the direction of surfactant F127 via an evaporation-induced-self-assembling process and then were closed by post-grafting long chain fluoroalkylsilane. The grazing incidence small angle X-ray scattering (GISAXS) and the X-ray reflectivity (XRR) results indicated that the mesopores in the coating constructed a Fmmm orthorhombic symmetry structure with a (010) plane parallel to the substrate. Cage-like mesopores were confirmed by nitrogen adsorption-desorption analysis. The obtained coatings showed low surface roughness, excellent abrase-resistance and high transmittance of 100% on quartz substrate. Especially, the decrease of transmittance tested with polydimethylsiloxane pollution in vacuum within one-month was as small as 0.02%. The laser induced damage threshold was up to 59.8 J cm(-2) at a 12 ns laser pulse of 1053 nm wavelength. This work provides an alternative way to fabricate AR coatings with high stability. PMID:25000419

  6. Incorporation of anti-inflammatory agent into mesoporous silica.

    PubMed

    Braz, Wilson Rodrigues; Rocha, Natállia Lamec; de Faria, Emerson H; Silva, Márcio L A E; Ciuffi, Katia J; Tavares, Denise C; Furtado, Ricardo Andrade; Rocha, Lucas A; Nassar, Eduardo J

    2016-09-23

    The unique properties of macroporous, mesoporous, and microporous systems, including their ability to accommodate molecules of different sizes inside their pores and to act as drug delivery systems, have been the object of extensive studies. In this work, mesoporous silica with hexagonal structure was obtained by template synthesis via the sol-gel process. The resulting material was used as support to accommodate the anti-inflammatory agent indomethacin. The alkaline route was used to prepare the mesoporous silica; cetyltrimethylammonium bromide was employed as porogenic agent. The silica particles were functionalized with 3-aminopropyltriethoxysilane alkoxide (APTES) by the sol-gel post-synthesis method. Indomethacin was incorporated into the silica functionalized with APTES and into non-functionalized silica. The resulting systems were characterized by x-ray diffraction (XRD), specific area, infrared spectroscopy, and thermal analyses (TGA). XRD attested to formation of mesoporous silica with hexagonal structure. This structure remained after silica functionalization with APTES and incorporation of indomethacin. Typical infrared spectroscopy vibrations and organic material decomposition during TGA confirmed silica functionalization and drug incorporation. The specific surface area and pore volume of the functionalized material incorporated with indomethacin decreased as compared with the specific surface area and pore volume of the non-functionalized silica containing no drug, suggesting both the functionalizing agent and the drug were present in the silica. Cytotoxicity tests conducted on normal fibroblasts (GM0479A) cells attested that the silica matrix containing indomethacin was less toxic than the free drug. PMID:27533108

  7. CO₂ adsorption on amine-functionalized periodic mesoporous benzenesilicas.

    PubMed

    Sim, Kyohyun; Lee, Nakwon; Kim, Joonseok; Cho, Eun-Bum; Gunathilake, Chamila; Jaroniec, Mietek

    2015-04-01

    CO2 adsorption was investigated on amine-functionalized mesoporous silica (SBA-15) and periodic mesoporous organosilica (PMO) samples. Hexagonally (p6mm) ordered mesoporous SBA-15 and benzene-PMO (BPMO) samples were prepared in the presence of Pluronic P123 block copolymer template under acidic conditions. Three kinds of amine-containing organosilanes and polyethylenimine were used to functionalize SBA-15 and BPMO. Small-angle X-ray scattering and nitrogen adsorption isotherms showed that these samples featured ordered mesostructure, high surface area, and narrow pore size distributions. Solid-state (13)C- and (29)Si cross-polarization magic-angle spinning NMR spectra showed chemical linkage between amine-containing modifiers and the surface of mesoporous materials. The chemically linked amine-containing modifiers were found to be on both the inner and outer surfaces. N-[3-(trimethoxysilyl)propyl]ethylenediamine-modified BPMO (A2-BPMO) sample exhibited the highest CO2 uptake (i.e., ∼3.03 mmol/g measured on a volumetric adsorption analyzer) and the fastest adsorption rate (i.e., ∼13 min to attain 90% of the maximum amount) among all the samples studied. Selectivity and reproducibility measurements for the A2-BPMO sample showed quite good performance in flowing N2 gas at 40 mL/min and CO2 gas of 60 mL/min at 25 °C. PMID:25742049

  8. Chemical vapor deposition of mesoporous graphene nanoballs for supercapacitor.

    PubMed

    Lee, Jung-Soo; Kim, Sun-I; Yoon, Jong-Chul; Jang, Ji-Hyun

    2013-07-23

    A mass-producible mesoporous graphene nanoball (MGB) was fabricated via a precursor-assisted chemical vapor deposition (CVD) technique for supercapacitor application. Polystyrene balls and reduced iron created under high temperature and a hydrogen gas environment provide a solid carbon source and a catalyst for graphene growth during the precursor-assisted CVD process, respectively. Carboxylic acid and sulfonic acid functionalization of the polystyrene ball facilitates homogeneous dispersion of the hydrophobic polymer template in the metal precursor solution, thus, resulting in a MGB with a uniform number of graphene layers. The MGB is shown to have a specific surface area of 508 m(2)/g and is mesoporous with a mean mesopore diameter of 4.27 nm. Mesopores are generated by the removal of agglomerated iron domains, permeating down through the soft polystyrene spheres and providing the surface for subsequent graphene growth during the heating process in a hydrogen environment. This technique requires only drop-casting of the precursor/polystyrene solution, allowing for mass-production of multilayer MGBs. The supercapacitor fabricated by the use of the MGB as an electrode demonstrates a specific capacitance of 206 F/g and more than 96% retention of capacitance after 10,000 cycles. The outstanding characteristics of the MGB as an electrode for supercapacitors verify the strong potential for use in energy-related areas. PMID:23782238

  9. Antibacterial performance of nanocrystallined titania confined in mesoporous silica nanotubes.

    PubMed

    Cendrowski, Krzysztof; Peruzynska, Magdalena; Markowska-Szczupak, Agata; Chen, Xuecheng; Wajda, Anna; Lapczuk, Joanna; Kurzawski, Mateusz; Kalenczuk, Ryszard J; Drozdzik, Marek; Mijowska, Ewa

    2014-06-01

    In this paper, we study synthesis and characteristics of mesoporous silica nanotubes modified by titanium dioxide, as well as their antimicrobial properties and influence on mitochondrial activity of mouse fibroblast L929. Nanocrystalized titania is confined in mesopores of silica nanotubes and its light activated antibacterial response is revealed. The analysis of the antibacterial effect on Escherichia coli. (ATCC 25922) shows strong enhancement during irradiation with the artificial visible and ultraviolet light in respect to the commercial catalyst and control sample free from the nanomaterials. In darkness, the mesoporous silica/titania nanostructures exhibited antibacterial activity dependent on the stirring speed of the suspension containing nanomaterials. Obtained micrograph proved internalization of the sample into the microorganism trough the cell membrane. The analysis of the mitochondrial activity and amount of lactate dehydrogenase released from mouse fibroblast cells L929 in the presence of the sample were determined with LDH and WST1 assays, respectively. The synthesized silica/titania antibacterial agent also exhibits pronounced photoinduced inactivation of the bacterial growth under the artificial visible and UV light irritation in respect to the commercial catalyst. Additionally, mesoporous silica/titania nanotubes were characterized in details by means of high resolution transmission electron microscopy (HR-TEM), XRD and BET Isotherm. PMID:24676537

  10. Solution Plasma Process for Template Removal in Mesoporous Silica Synthesis

    NASA Astrophysics Data System (ADS)

    Pootawang, Panuphong; Saito, Nagahiro; Takai, Osamu

    2010-12-01

    The plasma discharge in aqueous solution was scientifically studied and applied to template removal in mesoporous silica synthesis. Highly dispersed spherical mesoporous silica particles were synthesized by the ternary surfactant system containing the Pluronic P123 copolymer (EO20PO69EO20), sodium dodecylbenzene sulfonate, and 1,1,2,2,3,3,4,4,4-nonafluoro-1-butane sulfonate, via the sol-gel method in acid solutions. The solution plasma process (SPP), instead of conventional thermal calcinations, was used to remove the template. The mechanism of the removal of the organic template occurred via oxidation by the hydroxyl radicals generated during discharge. The transformation of a mesopore structure from a disordered wormlike structure to a hexagonally arranged structure was observed by X-ray diffraction analysis and was confirmed by transmission electron microscopy. The results of the thermal analysis and functional group identification of mesoporous silica after SPP showed evidence of organic template removal. The surface area calculated using the Brunauer-Emmett-Teller (BET) theory and the mean pore diameter results could be used to evaluate the plasma efficiency, demonstrating that this method does not affect the pore size in the case of discharge in a solution of pH 3 compared with the results of thermal calcination. Hence, SPP was proved to be highly efficient for organic template removal, exhibiting short consumption time and less contamination.

  11. Bifunctional mesoporous silicas with clearly distinguished localization of grafted groups

    NASA Astrophysics Data System (ADS)

    Roik, N. V.; Belyakova, L. A.

    2013-12-01

    Bifunctional mesoporous silicas with clearly distinguished localization of grafted groups on the surface of particles and inside their pores were obtained by means of sol-gel synthesis with postsynthetic vapor-phase treatment in vacuum. It was found that the synthesized materials have the hexagonally ordered porous structure typical of MCM-41 type silica.

  12. Ordered mesoporous carbon catalyst for dehydrogenation of propane to propylene.

    PubMed

    Liu, Lei; Deng, Qing-Fang; Agula, Bao; Zhao, Xu; Ren, Tie-Zhen; Yuan, Zhong-Yong

    2011-08-01

    Metal-free ordered mesoporous carbons were demonstrated to be robust catalysts for direct dehydrogenation of propane to propylene, in the absence of any auxiliary steam, exhibiting high activity and selectivity, as well as long catalytic stability, in comparison with nanostructured carbons. PMID:21687889

  13. Low TCR nanocomposite strain gages

    NASA Technical Reports Server (NTRS)

    Gregory, Otto J. (Inventor); Chen, Ximing (Inventor)

    2012-01-01

    A high temperature thin film strain gage sensor capable of functioning at temperatures above 1400.degree. C. The sensor contains a substrate, a nanocomposite film comprised of an indium tin oxide alloy, zinc oxide doped with alumina or other oxide semiconductor and a refractory metal selected from the group consisting of Pt, Pd, Rh, Ni, W, Ir, NiCrAlY and NiCoCrAlY deposited onto the substrate to form an active strain element. The strain element being responsive to an applied force.

  14. Probabilistic Simulation for Nanocomposite Fracture

    NASA Technical Reports Server (NTRS)

    Chamis, Christos C.

    2010-01-01

    A unique probabilistic theory is described to predict the uniaxial strengths and fracture properties of nanocomposites. The simulation is based on composite micromechanics with progressive substructuring down to a nanoscale slice of a nanofiber where all the governing equations are formulated. These equations have been programmed in a computer code. That computer code is used to simulate uniaxial strengths and fracture of a nanofiber laminate. The results are presented graphically and discussed with respect to their practical significance. These results show smooth distributions from low probability to high.

  15. Rapid synthesis of ordered hexagonal mesoporous silica and their incorporation with Ag nanoparticles by solution plasma

    SciTech Connect

    Pootawang, Panuphong; Saito, Nagahiro; Takai, Osamu; Lee, Sang Yul

    2012-10-15

    Graphical abstract: Overall reactions of mesoporous silica and AgNPs-incorporated mesoporous silica syntheses by solution plasma process (SPP). Highlights: ► SPP for rapid synthesis of mesoporous silica. ► SPP for rapid synthesis of mesoporous silica and AgNPs incorporation. ► Higher surface area and larger pore diameter of mesoporous silica synthesized by SPP. -- Abstract: Rapid synthesis of silica with ordered hexagonal mesopore arrangement was obtained using solution plasma process (SPP) by discharging the mixture of P123 triblock copolymer/TEOS in acid solution. SPP, moreover, was utilized for Ag nanoparticles (AgNPs) incorporation in silica framework as one-batch process using silver nitrate (AgNO{sub 3}) solution as precursor. The turbid silicate gel was clearly observed after discharge for 1 min and the white precipitate formed at 3 min. The mesopore with hexagonal arrangement and AgNPs were observed in mesoporous silica. Two regions of X-ray diffraction patterns (2θ < 2° and 2θ = 35–90°) corresponded to the mesoporous silica and Ag nanocrystal characteristics. Comparing with mesoporous silica prepared by a conventional sol–gel route, surface area and pore diameter of mesoporous silica prepared by solution plasma were observed to be larger. In addition, the increase in Ag loading resulted in the decrease in surface area with insignificant variation in the pore diameter of mesoporous silica. SPP could be successfully utilized not only to enhance gelation time but also to increase surface area and pore diameter of mesoporous silica.

  16. A magnetic mesoporous silica nanoparticle-based drug delivery system for photosensitive cooperative treatment of cancer with a mesopore-capping agent and mesopore-loaded drug

    NASA Astrophysics Data System (ADS)

    Knežević, Nikola Ž.; Lin, Victor S.-Y.

    2013-01-01

    Lately, there has been a growing interest in anticancer therapy with a combination of different drugs that work by different mechanisms of action, which decreases the possibility that resistant cancer cells will develop. Herein we report on the development of a drug delivery system for photosensitive delivery of a known anticancer drug camptothecin along with cytotoxic cadmium sulfide nanoparticles from a magnetic drug nanocarrier. Core-shell nanoparticles consisting of magnetic iron-oxide-cores and mesoporous silica shells are synthesized with a high surface area (859 m2 g-1) and hexagonal packing of mesopores, which are 2.6 nm in diameter. The mesopores are loaded with anticancer drug camptothecin while entrances of the mesopores are blocked with 2-nitro-5-mercaptobenzyl alcohol functionalized CdS nanoparticles through a photocleavable carbamate linkage. Camptothecin release from this magnetic drug delivery system is successfully triggered upon irradiation with UV light, as measured by fluorescence spectroscopy. Photosensitive anticancer activity of the drug delivery system is monitored by viability studies on Chinese hamster ovarian cells. The treatment of cancer cells with drug loaded magnetic material leads to a decrease in viability of the cells due to the activity of capping CdS nanoparticles. Upon exposure to low power UV light (365 nm) the loaded camptothecin is released which induces additional decrease in viability of CHO cells. Hence, the capping CdS nanoparticles and loaded camptothecin exert a cooperative anticancer activity. Responsiveness to light irradiation and magnetic activity of the nanocarrier enable its potential application for selective targeted treatment of cancer.

  17. Polymer/metal nanocomposites for biomedical applications.

    PubMed

    Zare, Yasser; Shabani, Iman

    2016-03-01

    Polymer/metal nanocomposites consisting of polymer as matrix and metal nanoparticles as nanofiller commonly show several attractive advantages such as electrical, mechanical and optical characteristics. Accordingly, many scientific and industrial communities have focused on polymer/metal nanocomposites in order to develop some new products or substitute the available materials. In the current paper, characteristics and applications of polymer/metal nanocomposites for biomedical applications are extensively explained in several categories including strong and stable materials, conductive devices, sensors and biomedical products. Moreover, some perspective utilizations are suggested for future studies. PMID:26706522

  18. Synthesis and characterization of elastomeric nanocomposites

    SciTech Connect

    Burnside, S.D.; Giannelis, E.P.

    1995-12-31

    We present work on polymeric matrices reinforced on a molecular or nanoscale level with layered silicates. Previously, thermosetting and thermoplastic nanocomposites have realized great enhancements in barrier and mechanical properties with the latter increasing dramatically above T{sub g}. Using melt processing, PDMS-silicate nanocomposites have been synthesized by first delaminating the silicate in the polymer matrix followed by crosslinking. The nanocomposites exhibit decreased swelling in toluene and increased thermal stability. The increased swelling resistance is attributed to strong reinforcement/matrix interactions and the large surface area attainable by delamination and dispersion of the silicate particles in the polymer matrix.

  19. Colorimetric Quantification of Glucose and Cholesterol in Human Blood Using a Nanocomposite Entrapping Magnetic Nanoparticles and Oxidases.

    PubMed

    Kim, Moon Il; Cho, Daeyeon; Park, Hyun Gyu

    2015-10-01

    In this study, a microscale well-plate colorimetric assay for the multiplexed detection of glucose and cholesterol in clinical human blood samples has been developed. This system utilized one-pot nanocomposite entrapping Fe3O4 magnetic nanoparticles (MNPs) as peroxidase mimetics and glucose oxidase (GOx)/cholesterol oxidase (ChOx) in mesoporous silica to detect glucose and cholesterol in blood samples. The sensing mechanism involves the generation of H2O2 by the catalytic action of an immobilized oxidase on the target molecules in the sample. This subsequently activates the MNPs in the mesopores, thereby leading to the conversion of the substrate into a colored end product. This strategy is used to detect the target glucose or cholesterol molecules in the concentration range of 15-250 mg/dL. The response is highly linear and the lower detection limit is 7.5 mg/dL. The aforementioned colorimetric assay is extremely convenient, and it exhibits a high degree of linearity, precision, and reproducibility when employing real human blood samples. Therefore, this assay can be used in clinical practice for the multiplexed and reliable quantification of glucose and cholesterol. PMID:26726446

  20. Synthesis of mesoporous zeolite single crystals with cheap porogens

    SciTech Connect

    Tao Haixiang; Li Changlin; Ren Jiawen; Wang Yanqin; Lu Guanzhong

    2011-07-15

    Mesoporous zeolite (silicalite-1, ZSM-5, TS-1) single crystals have been successfully synthesized by adding soluble starch or sodium carboxymethyl cellulose (CMC) to a conventional zeolite synthesis system. The obtained samples were characterized by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), scanning electron microscopy (SEM), transmission electron microscopy (TEM), nitrogen sorption analysis, {sup 27}Al magic angle spinning nuclear magnetic resonance ({sup 27}Al MAS NMR), temperature-programmed desorption of ammonia (NH{sub 3}-TPD) and ultraviolet-visible spectroscopy (UV-vis). The SEM images clearly show that all zeolite crystals possess the similar morphology with particle size of about 300 nm, the TEM images reveal that irregular intracrystal pores are randomly distributed in the whole crystal. {sup 27}Al MAS NMR spectra indicate that nearly all of the Al atoms are in tetrahedral co-ordination in ZSM-5, UV-vis spectra confirm that nearly all of titanium atoms are incorporated into the framework of TS-1. The catalytic activity of meso-ZSM-5 in acetalization of cyclohexanone and meso-TS-1 in hydroxylation of phenol was also studied. The synthesis method reported in this paper is cost-effective and environmental friendly, can be easily expended to prepare other hierarchical structured zeolites. - Graphical abstract: Mesoporous zeolite single crystals were synthesized by using cheap porogens as template. Highlights: > Mesoporous zeolite (silicalite-1, ZSM-5, TS-1) single crystals were synthesized. > Soluble starch or sodium carboxymethyl cellulose (CMC) was used as porogens. > The mesoporous zeolites had connected mesopores although closed pores existed. > Higher catalytic activities were obtained.

  1. Mesoporous-silica films, fibers, and powders by evaporation

    DOEpatents

    Bruinsma, Paul J.; Baskaran, Suresh; Bontha, Jagannadha R.; Liu, Jun

    2008-05-06

    This invention pertains to surfactant-templated nanometer-scale porosity of a silica precursor solution and forming a mesoporous material by first forming the silica precursor solution into a preform having a high surface area to volume ratio, then rapid drying or evaporating a solvent from the silica precursor solution. The mesoporous material may be in any geometric form, but is preferably in the form of a film, fiber, powder or combinations thereof. The rapid drying or evaporation of solvent from the solution is accomplished by layer thinning, for example spin casting, liquid drawing, and liquid spraying respectively. Production of a film is by layer thinning, wherein a layer of the silica precursor solution is formed on a surface followed by removal of an amount of the silica precursor solution and leaving a geometrically thinner layer of the silica precursor solution from which the solvent quickly escapes via evaporation. Layer thinning may be by any method including but not limited to squeegeeing and/or spin casting. In powder formation by spray drying, the same conditions of fast drying exists as in spin-casting (as well as in fiber spinning) because of the high surface-area to volume ratio of the product. When a powder is produced by liquid spraying, the particles or micro-bubbles within the powder are hollow spheres with walls composed of mesoporous silica. Mesoporous fiber formation starts with a similar silica precursor solution but with an added pre-polymer making a pituitous mixture that is drawn into a thin strand from which solvent is evaporated leaving the mesoporous fiber(s).

  2. Mesoporous-silica films, fibers, and powders by evaporation

    DOEpatents

    Bruinsma, Paul J.; Baskaran, Suresh; Bontha, Jagannadha R.; Liu, Jun

    1999-01-01

    This invention pertains to surfactant-templated nanometer-scale porosity of a silica precursor solution and forming a mesoporous material by first forming the silica precursor solution into a preform having a high surface area to volume ratio, then rapid drying or evaporating a solvent from the silica precursor solution. The mesoporous material may be in any geometric form, but is preferably in the form of a film, fiber, powder or combinations thereof. The rapid drying or evaporation of solvent from the solution is accomplished by layer thinning, for example spin casting, liquid drawing, and liquid spraying respectively. Production of a film is by layer thinning, wherein a layer of the silica precursor solution is formed on a surface followed by removal of an amount of the silica precursor solution and leaving a geometrically thinner layer of the silica precursor solution from which the solvent quickly escapes via evaporation. Layer thinning may be by any method including but not limited to squeegeeing and/or spin casting. In powder formation by spray drying, the same conditions of fast drying exists as in spin-casting (as well as in fiber spinning) because of the high surface-area to volume ratio of the product. When a powder is produced by liquid spraying, the particles or micro-bubbles within the powder are hollow spheres with walls composed of mesoporous silica. Mesoporous fiber formation starts with a similar silica precursor solution but with an added pre-polymer making a pituitous mixture that is drawn into a thin strand from which solvent is evaporated leaving the mesoporous fiber(s).

  3. Mesoporous-silica films, fibers, and powders by evaporation

    DOEpatents

    Bruinsma, P.J.; Baskaran, S.; Bontha, J.R.; Liu, J.

    1999-07-13

    This invention pertains to surfactant-templated nanometer-scale porosity of a silica precursor solution and forming a mesoporous material by first forming the silica precursor solution into a preform having a high surface area to volume ratio, then rapid drying or evaporating a solvent from the silica precursor solution. The mesoporous material may be in any geometric form, but is preferably in the form of a film, fiber, powder or combinations thereof. The rapid drying or evaporation of solvent from the solution is accomplished by layer thinning, for example spin casting, liquid drawing, and liquid spraying respectively. Production of a film is by layer thinning, wherein a layer of the silica precursor solution is formed on a surface followed by removal of an amount of the silica precursor solution and leaving a geometrically thinner layer of the silica precursor solution from which the solvent quickly escapes via evaporation. Layer thinning may be by any method including but not limited to squeegeeing and/or spin casting. In powder formation by spray drying, the same conditions of fast drying exists as in spin-casting (as well as in fiber spinning) because of the high surface-area to volume ratio of the product. When a powder is produced by liquid spraying, the particles or micro-bubbles within the powder are hollow spheres with walls composed of mesoporous silica. Mesoporous fiber formation starts with a similar silica precursor solution but with an added pre-polymer making a pituitous mixture that is drawn into a thin strand from which solvent is evaporated leaving the mesoporous fiber(s). 24 figs.

  4. Magnetic mesoporous materials for removal of environmental wastes

    SciTech Connect

    Kim, Byoung Chan; Lee, Jinwoo; Um, Wooyong; Kim, Jaeyun; Joo, Jin; Lee, Jin Hyung; Kwak, Ja Hun; Kim, Jae Hyun; Lee, Changha; Lee, Hongshin; Addleman, Raymond S.; Hyeon, Taeghwan; Gu, Man Bock; Kim, Jungbae

    2011-09-15

    We have synthesized two different magnetic mesoporous materials that can be easily separated from aqueous solutions by applying a magnetic field. Synthesized magnetic mesoporous materials, Mag-SBA-15 (magnetic ordered mesoporous silica) and Mag-OMC (magnetic ordered mesoporous carbon), have a high loading capacity of contaminants due to high surface area of the supports and high magnetic activity due to the embedded iron oxide particles. Application of surface-modified Mag-SBA-15 was investigated for the collection of mercury from water. The mercury adsorption using Mag-SBA-15 was rapid during the initial contact time and reached a steady-state condition, with an uptake of approximately 97% after 7 hours. Application of Mag-OMC for collection of organics from water, using fluorescein as an easily trackable model analyte, was explored. The fluorescein was absorbed into Mag-OMC within minutes and the fluorescent intensity of solution was completely disappeared after an hour. In another application, Mag-SBA-15 was used as a host of tyrosinase, and employed as recyclable catalytic scaffolds for tyrosinase-catalyzed biodegradation of catechol. Tyrosinase aggregates in Mag-SBA-15, prepared in a two step process of tyrosinase adsorption and crosslinking, could be used repeatedly for catechol degradation with no serious loss of enzyme activity. Considering these results of cleaning up water from toxic inorganic, organic and biochemical contaminants, magnetic mesoporous materials have a great potential to be employed for the removal of environmental contaminants and potentially for the application in large-scale wastewater treatment plants.

  5. Noble Metal Nanoparticle-loaded Mesoporous Oxide Microspheres for Catalysis

    NASA Astrophysics Data System (ADS)

    Jin, Zhao

    Noble metal nanoparticles/nanocrystals have attracted much attention as catalysts due to their unique characteristics, including high surface areas and well-controlled facets, which are not often possessed by their bulk counterparts. To avoid the loss of their catalytic activities brought about by their size and shape changes during catalytic reactions, noble metal nanoparticles/nanocrystals are usually dispersed and supported finely on solid oxide supports to prevent agglomeration, nanoparticle growth, and therefore the decrease in the total surface area. Moreover, metal oxide supports can also play important roles in catalytic reactions through the synergistic interactions with loaded metal nanoparticles/nanocrystals. In this thesis, I use ultrasonic aerosol spray to produce hybrid microspheres that are composed of noble metal nanoparticles/nanocrystals embedded in mesoporous metal oxide matrices. The mesoporous metal oxide structure allows for the fast diffusion of reactants and products as well as confining and supporting noble metal nanoparticles. I will first describe my studies on noble metal-loaded mesoporous oxide microspheres as catalysts. Three types of noble metals (Au, Pt, Pd) and three types of metal oxide substrates (TiO2, ZrO2, Al 2O3) were selected, because they are widely used for practical catalytic applications involved in environmental cleaning, pollution control, petrochemical, and pharmaceutical syntheses. By considering every possible combination of the noble metals and oxide substrates, nine types of catalyst samples were produced. I characterized the structures of these catalysts, including their sizes, morphologies, crystallinity, and porosities, and their catalytic performances by using a representative reduction reaction from nitrobenzene to aminobenzene. Comparison of the catalytic results reveals the effects of the different noble metals, their incorporation amounts, and oxide substrates on the catalytic abilities. For this particular

  6. Light-Induced Hydrogel Based on Tumor-Targeting Mesoporous Silica Nanoparticles as a Theranostic Platform for Sustained Cancer Treatment.

    PubMed

    Chen, Xin; Liu, Zhongning; Parker, Stephen G; Zhang, Xiaojin; Gooding, J Justin; Ru, Yanyan; Liu, Yuhong; Zhou, Yongsheng

    2016-06-29

    Herein, we report a facile fabrication of a polymer (azobenzene and α-cyclodextrin-functionalized hyaluronic acid) and gold nanobipyramids (AuNBs) conjugated mesoporous silica nanoparticles (MSNs) to be used as an injectable drug delivery system for sustained cancer treatment. Because of the specific affinity between the hyaluronic acid (HA) on MSNs and the CD44 antigen overexpressed on tumor cells, the MSNs can selectively attach to tumor cells. The nanocomposite material then exploits thermoresponsive interactions between α-cyclodextrin and azobenzene, and the photothermal properties of gold nanobipyramids, to in situ self-assemble into a hydrogel under near-infrared (NIR) radiation. Upon gelation, the drug (doxorubicin)-loaded MSNs carriers were enclosed in the HA network of the hydrogel, whereas further degradation of the HA in the hydrogel due to the upregulation of hyaluronidase (HAase) around the tumor tissue will result in the release of MSNs from the hydrogel, which can then be taken by tumor cells and deliver their drug to the cell nuclei. This design is able to provide a microenvironment with rich anticancer drugs in, and around, the tumor tissue for time periods long enough to prevent the recrudescence of the disease. The extra efficacy that this strategy affords builds upon the capabilities of conventional therapies. PMID:27265514

  7. Luminescent GdVO4:Eu3+ functionalized mesoporous silica nanoparticles for magnetic resonance imaging and drug delivery.

    PubMed

    Huang, Shanshan; Cheng, Ziyong; Ma, Ping'an; Kang, Xiaojiao; Dai, Yunlu; Lin, Jun

    2013-05-14

    Luminescent GdVO4:Eu(3+) nanophosphor functionalized mesoporous silica nanoparticles (MSN) were prepared (denoted as GdVO4:Eu(3+)@MSN). The in vitro cytotoxicity tests show that the sample has good biocompatibility, which indicates that the nanocomposite could be a promising candidate for drug delivery. Flow cytometry and confocal laser scanning microscopy (CLSM) confirm that the sample can be effectively taken up by SKOV3 ovarian cancer cells and A549 lung adenocarcinoma cells. It was also shown that the GdVO4:Eu(3+)@MSN brightened the T1-weighted images and enhanced the r1 relaxivity of water protons, which suggested that they could act as T1 contrast agents for magnetic resonance (MR) imaging. It was found that the carriers present a pH-dependent drug release behavior for doxorubicin (DOX). The composites show a red emission under UV irradiation due to the GdVO4:Eu(3+) nanophosphors. Furthermore, the PL intensity of the composite shows correlation with the cumulative release of DOX. These results suggest that the composite can potentially act as a multifunctional drug carrier system with luminescent tagging, MR imaging and pH-controlled release property for DOX. PMID:23474744

  8. Targeted Mesoporous Iron Oxide Nanoparticles-Encapsulated Perfluorohexane and a Hydrophobic Drug for Deep Tumor Penetration and Therapy

    PubMed Central

    Su, Yu-Lin; Fang, Jen-Hung; Liao, Chia-Ying; Lin, Chein-Ting; Li, Yun-Ting; Hu, Shang-Hsiu

    2015-01-01

    A magneto-responsive energy/drug carrier that enhances deep tumor penetration with a porous nano-composite is constructed by using a tumor-targeted lactoferrin (Lf) bio-gate as a cap on mesoporous iron oxide nanoparticles (MIONs). With a large payload of a gas-generated molecule, perfluorohexane (PFH), and a hydrophobic anti-cancer drug, paclitaxel (PTX), Lf-MIONs can simultaneously perform bursting gas generation and on-demand drug release upon high-frequency magnetic field (MF) exposure. Biocompatible PFH was chosen and encapsulated in MIONs due to its favorable phase transition temperature (56 °C) and its hydrophobicity. After a short-duration MF treatment induces heat generation, the local pressure increase via the gasifying of the PFH embedded in MION can substantially rupture the three-dimensional tumor spheroids in vitro as well as enhance drug and carrier penetration. As the MF treatment duration increases, Lf-MIONs entering the tumor spheroids provide an intense heat and burst-like drug release, leading to superior drug delivery and deep tumor thermo-chemo-therapy. With their high efficiency for targeting tumors, Lf-MIONs/PTX-PFH suppressed subcutaneous tumors in 16 days after a single MF exposure. This work presents the first study of using MF-induced PFH gasification as a deep tumor-penetrating agent for drug delivery. PMID:26379789

  9. Structure and Photoluminescent Properties of ZnO Encapsulated in Mesoporous Silica SBA-15 Fabricated by Two-Solvent Strategy

    PubMed Central

    2009-01-01

    The two-solvent method was employed to prepare ZnO encapsulated in mesoporous silica (ZnO/SBA-15). The prepared ZnO/SBA-15 samples have been studied by X-ray diffraction, transmission electron microscope, X-ray photoelectron spectroscopy, nitrogen adsorption–desorption isotherm, and photoluminescence spectroscopy. The ZnO/SBA-15 nanocomposite has the ordered hexagonal mesostructure of SBA-15. ZnO clusters of a high loading are distributed in the channels of SBA-15. Photoluminescence spectra show the UV emission band around 368 nm, the violet emission around 420 nm, and the blue emission around 457 nm. The UV emission is attributed to band-edge emission of ZnO. The violet emission results from the oxygen vacancies on the ZnO–SiO2interface traps. The blue emission is from the oxygen vacancies or interstitial zinc ions of ZnO. The UV emission and blue emission show a blue-shift phenomenon due to quantum-confinement-induced energy gap enhancement of ZnO clusters. The ZnO clusters encapsulated in SBA-15 can be used as light-emitting diodes and ultraviolet nanolasers. PMID:20596369

  10. A facile method for synthesis of N-doped ZnO mesoporous nanospheres and enhanced photocatalytic activity.

    PubMed

    Zhang, DongEn; Gong, JunYan; Ma, JuanJuan; Han, GuiQuan; Tong, ZhiWei

    2013-12-21

    A facile synthesis route is reported for preparation of N-doped mesoporous ZnO nanospheres by a solvothermal treatment of Zn(NO3)2·6H2O which provides a source of both zinc and nitrogen. A variety of different spectroscopic and analytical techniques, such as powder X-ray diffraction (XRD), transmission electron microscopy (TEM), UV-vis and X-ray photoelectron (XPS) spectroscopies were used to characterize the physicochemical properties of catalysts. The photocatalytic activities of the composites were evaluated by the degree of degradation of rhodamine B in aqueous solutions at room temperature with near-UV light irradiation. These nanocomposites exhibit higher photocatalytic activity compared with pure ZnO nanoparticles. The enhancement of photocatalytic activity of N-doped ZnO nanoparticles is mainly attributed to their absorption of more photons and reduced electron-hole pair recombination. Our one-step, environmentally friendly synthetic method may provide a new means of designing and synthesizing series of N-doped metal oxide semiconductors for use in photo-assisted catalytic reactions. PMID:24068002

  11. Electroactive functional hybrid layered nanocomposites

    SciTech Connect

    Destri, Giovanni Li; Torrisi, Vanna; Marletta, Giovanni

    2012-07-11

    Two methodologies to build new nanostructured hybrid layered nanocomposites are presented. The first one involves the preparation of hybrid metal/polymer nanolayers (NLs) by combining two monolayer preparation techniques: Horizontal Precipitation Langmuir Blodgett method (HP-ML), for copolymer monolayers and sputter deposition technique, for Au NLs deposition. The second methodology is aimed to prepare regular arrays of nanopores, with diameter ranging between 40-100 nm, in ultra-thin films of electroactive polymers, to obtain embedded regular arrays of nanopores filled by a further electroactive organic component. The produced hybrid MLs have been characterized by means of X-ray Photoelectron Spectroscopy (XPS), Atomic Force Microscopy (AFM) and Grazing Incidence X-ray Diffraction (GI-XRD). In the first case, current-voltage (I-V) measurements demonstrate that the multilayers exhibit a bipolar conduction behaviour (electrons and holes carriers), with a peculiar transition in the nature of the majority carriers (from holes to electrons) above a threshold number of bilayers. In the second case, it is found that the degree of pore filling, as well as the polymer crystallinity can be easily modulated, prompting the tuning of the photoresponse of the nanocomposites.

  12. Electroactive functional hybrid layered nanocomposites

    NASA Astrophysics Data System (ADS)

    Destri, Giovanni Li; Torrisi, Vanna; Marletta, Giovanni

    2012-07-01

    Two methodologies to build new nanostructured hybrid layered nanocomposites are presented. The first one involves the preparation of hybrid metal/polymer nanolayers (NLs) by combining two monolayer preparation techniques: Horizontal Precipitation Langmuir Blodgett method (HP-ML), for copolymer monolayers and sputter deposition technique, for Au NLs deposition. The second methodology is aimed to prepare regular arrays of nanopores, with diameter ranging between 40-100 nm, in ultra-thin films of electroactive polymers, to obtain embedded regular arrays of nanopores filled by a further electroactive organic component. The produced hybrid MLs have been characterized by means of X-ray Photoelectron Spectroscopy (XPS), Atomic Force Microscopy (AFM) and Grazing Incidence X-ray Diffraction (GI-XRD). In the first case, current-voltage (I-V) measurements demonstrate that the multilayers exhibit a bipolar conduction behaviour (electrons and holes carriers), with a peculiar transition in the nature of the majority carriers (from holes to electrons) above a threshold number of bilayers. In the second case, it is found that the degree of pore filling, as well as the polymer crystallinity can be easily modulated, prompting the tuning of the photoresponse of the nanocomposites.

  13. Multitasking mesoporous nanomaterials for biorefinery applications

    NASA Astrophysics Data System (ADS)

    Kandel, Kapil

    Mesoporous silica nanoparticles (MSNs) have attracted great interest for last two decades due to their unique and advantageous structural properties, such as high surface area, pore volume, stable mesostructure, tunable pore size and controllable particle morphology. The robust silica framework provides sites for organic modifications, making MSNs ideal platforms for adsorbents and supported organocatalysts. In addition, the pores of MSNs provide cavities/ channels for incorporation of metal and metal oxide nanoparticle catalysts. These supported metal nanoparticle catalysts benefit from confined local environments to enhance their activity and selectivity for various reactions. Biomass is considered as a sustainable feedstock with potential to replace diminishing fossil fuels for the production of biofuels. Among several strategies, one of the promising methods of biofuel production from biomass is to reduce the oxygen content of the feedstock in order to improve the energy density. This can be achieved by creating C-C bonds between biomass derived intermediates to increase the molecular weight of the final hydrocarbon molecules. In this context, pore size and organic functionality of MSNs are varied to obtain the ideal catalyst for a C-C bond forming reaction: the aldol condensation. The mechanistic aspects of this reaction in supported heterogeneous catalysts are explored. The modification of supported organocatalyst and the effect of solvent on the reaction are rationalized. The significance of two functional surfaces of MSNs is exploited by enzyme immobilization on the external surface and organo catalyst functionalization on the internal surface. Using this bifunctional catalyst, the tandem conversion of small chain alcohols into longer chain hydrocarbon molecules is demonstrated. The ability to incorporate metal and metal oxide nanoparticles in the pores and subsequent functionalization led to develop organic modified magnetic MSNs (OM-MSNs) for applications

  14. Multitasking mesoporous nanomaterials for biorefinery applications

    SciTech Connect

    Kandel, Kapil

    2013-01-01

    Mesoporous silica nanoparticles (MSNs) have attracted great interest for last two decades due to their unique and advantageous structural properties, such as high surface area, pore volume, stable mesostructure, tunable pore size and controllable particle morphology. The robust silica framework provides sites for organic modifications, making MSNs ideal platforms for adsorbents and supported organocatalysts. In addition, the pores of MSNs provide cavities/ channels for incorporation of metal and metal oxide nanoparticle catalysts. These supported metal nanoparticle catalysts benefit from confined local environments to enhance their activity and selectivity for various reactions. Biomass is considered as a sustainable feedstock with potential to replace diminishing fossil fuels for the production of biofuels. Among several strategies, one of the promising methods of biofuel production from biomass is to reduce the oxygen content of the feedstock in order to improve the energy density. This can be achieved by creating C-C bonds between biomass derived intermediates to increase the molecular weight of the final hydrocarbon molecules. In this context, pore size and organic functionality of MSNs are varied to obtain the ideal catalyst for a C-C bond forming reaction: the aldol condensation. The mechanistic aspects of this reaction in supported heterogeneous catalysts are explored. The modification of supported organocatalyst and the effect of solvent on the reaction are rationalized. The significance of two functional surfaces of MSNs is exploited by enzyme immobilization on the external surface and organo catalyst functionalization on the internal surface. Using this bifunctional catalyst, the tandem conversion of small chain alcohols into longer chain hydrocarbon molecules is demonstrated. The ability to incorporate metal and metal oxide nanoparticles in the pores and subsequent functionalization led to develop organic modified magnetic MSNs (OM-MSNs) for applications

  15. Direct coating of mesoporous titania on CTAB-capped gold nanorods

    NASA Astrophysics Data System (ADS)

    Zhao, Junwei; Xu, Pengyu; Li, Yue; Wu, Jian; Xue, Junfei; Zhu, Qiannan; Lu, Xuxing; Ni, Weihai

    2016-03-01

    We demonstrate a CTAB-templated approach towards direct coating of mesoporous titania on gold nanorods in aqueous solutions. The formation of the mesoporous shell is found to be closely correlated with CTAB concentration and the amount of the titania precursor. This approach can be readily extended to form mesoporous titania shells on other CTAB-capped nanoparticles.We demonstrate a CTAB-templated approach towards direct coating of mesoporous titania on gold nanorods in aqueous solutions. The formation of the mesoporous shell is found to be closely correlated with CTAB concentration and the amount of the titania precursor. This approach can be readily extended to form mesoporous titania shells on other CTAB-capped nanoparticles. Electronic supplementary information (ESI) available: Experimental details including chemicals, sample preparation, and characterization methods. UV-Vis extinction spectra, SEM images, and TEM images of AuNR@mTiO2 nanostructures. See DOI: 10.1039/c5nr05692f

  16. Synthesis, characterization and catalytic activity of a novel mesoporous ZSM-5 zeolite

    SciTech Connect

    Ma, Yuanyuan; Hu, Jing; Jia, Lihua; Li, Zhifang; Kan, Qiubin; Wu, Shujie

    2013-05-15

    Highlights: ► Mesoporous ZSM-5 zeolites. ► The strong acidic intensity. ► High activity for the alkylation of phenol and tert-butyl alcohol. ► Remarkable hydrothermal stability. - Abstract: A novel mesoporous ZSM-5 zeolite was hydrothermally synthesized using glucose as a template. Characterizations by XRD, TEM and nitrogen isotherms indicated that ZSM-5 possessed worm-like mesoporous. {sup 27}Al-MAS-NMR and NH{sub 3}-TPD showed that the mesoporous ZSM-5 preserved tetrahedral coordination aluminum and stronger acidity than conventional mesoporous material. As-prepared mesoporous ZSM-5 was successfully used in alkylation reaction of phenol with tert-butanol and exhibited significantly high phenol conversion and 2,4-DTBP selectivity. In addition, the hydrothermal stability was also studied by boiling in water for 7 days and displayed good results.

  17. Post-treatment and characterization of novel luminescent hybrid bimodal mesoporous silicas

    NASA Astrophysics Data System (ADS)

    Li, Yuzhen; Sun, Jihong; Wu, Xia; Lin, Li; Gao, Lin

    2010-08-01

    A novel luminescent hybrid bimodal mesoporous silicas (LHBMS) were synthesized via grafting 1,8-Naphthalic anhydride into the pore channels of bimodal mesoporous silicas (BMMs) for the first time. The resulting samples were characterized by powder X-ray diffraction (XRD), N 2 adsorption/desorption measurement, Fourier transform infrared spectroscopy (FT-IR), Transmission electron microscopy (TEM), UV-vis absorption spectroscopy, and Photoluminescence spectroscopy (PL). The results show that 1,8-Naphthalic anhydride organic groups have been successfully introduced into the mesopores of the BMMs and the hybrid silicas are of bimodal mesoporous structure with the ordered small mesopores of around 3 nm and the large mesopores of uniform intra-nanoparticle. The excellent photoluminescent performance of LHBMS has a blue shift compared to that of 2-[3-(triethoxysilyl) propyl-1 H-Benz [de]isoquinoline-1, 3(2 H)-dione, suggesting the existence of the quantum confinement effectiveness.

  18. Mechanical strength of carbon nanotube nickel nanocomposites

    NASA Astrophysics Data System (ADS)

    Sun, Ying; Sun, Jianren; Liu, Miao; Chen, Quanfang

    2007-12-01

    Carbon nanotubes (CNTs), including single-walled CNT (SWCNT) and multi-walled CNT (MWCNT), have been regarded as the stiffest and strongest materials ever developed and are promising reinforcement fillers for developing nanocomposites. However, the scientific community has been puzzled about the reinforcement efficiency. Here we report CNT-reinforced nickel nanocomposites fabricated with an innovative electrochemical co-deposition process for achieving good interfacial bonding between CNT and metallic matrices. Test results show that Ni/SWCNT composite produces a tensile strength as high as 2 GPa, which is more than three times stronger than that of pure nickel. The mechanical strength of Ni/CNT nanocomposites is dependent on CNT addition, while the fracture strain remains similar or better than that of pure nickel. The good reinforcement of CNT/metal nanocomposites is attributed to the good interfacial bonding as well as the stiffer matrix nature.

  19. Nanocomposite polymer electrolyte for rechargeable magnesium batteries

    SciTech Connect

    Shao, Yuyan; Rajput, Nav Nidhi; Hu, Jian Z.; Hu, Mary Y.; Liu, Tianbiao L.; Wei, Zhehao; Gu, Meng; Deng, Xuchu; Xu, Suochang; Han, Kee Sung; Wang, Jiulin; Nie, Zimin; Li, Guosheng; Zavadil, K.; Xiao, Jie; Wang, Chong M.; Henderson, Wesley A.; Zhang, Jiguang; Wang, Yong; Mueller, Karl T.; Persson, Kristin A.; Liu, Jun

    2014-12-28

    Nanocomposite polymer electrolytes present new opportunities for rechargeable magnesium batteries. However, few polymer electrolytes have demonstrated reversible Mg deposition/dissolution and those that have still contain volatile liquids such as tetrahydrofuran (THF). In this work, we report a nanocomposite polymer electrolyte based on poly(ethylene oxide) (PEO), Mg(BH4)2 and MgO nanoparticles for rechargeable Mg batteries. Cells with this electrolyte have a high coulombic efficiency of 98% for Mg plating/stripping and a high cycling stability. Through combined experiment-modeling investigations, a correlation between improved solvation of the salt and solvent chain length, chelation and oxygen denticity is established. Following the same trend, the nanocomposite polymer electrolyte is inferred to enhance the dissociation of the salt Mg(BH4)2 and thus improve the electrochemical performance. The insights and design metrics thus obtained may be used in nanocomposite electrolytes for other multivalent systems.

  20. Cellulose nanocrystals reinforced foamed nitrile rubber nanocomposites.

    PubMed

    Chen, Yukun; Zhang, Yuanbing; Xu, Chuanhui; Cao, Xiaodong

    2015-10-01

    Research on foamed nitrile rubber (NBR)/cellulose nanocrystals (CNs) nanocomposites is rarely found in the literatures. In this paper, CNs suspension and NBR latex was mixed to prepared the foamed NBR/CNs nanocomposites. We found that the CNs mainly located in the cell walls, effectively reinforcing the foamed NBR. The strong interaction between the CNs and NBR matrix restricted the mobility of NBR chains surrounding the CNs, hence increasing the crosslink density of the NBR matrix. CNs exhibited excellent reinforcement on the foamed NBR: a remarkable increase nearly 76% in the tensile strength of the foamed nanocomposites was achieved with a load of only 15 phr CNs. Enhanced mechanical properties make the foamed NBR/CNs nanocomposites a promising damping material for industrial applications with a potential to reduce the petroleum consumption. PMID:26076611

  1. Graphene oxide nanocomposites and their electrorheology

    SciTech Connect

    Zhang, Wen Ling; Liu, Ying Dan; Choi, Hyoung Jin

    2013-12-15

    Graphical abstract: - Highlights: • GO-based PANI, NCOPA and PS nanocomposites are prepared. • The nanocomposites are adopted as novel electrorheological (ER) candidates. • Their critical ER characteristics and dielectric performance are analyzed. • Typical ER behavior widens applications of GO-based nanocomposites. - Abstract: Graphene oxide (GO), a novel one-atom carbon system, has become one of the most interesting materials recently due to its unique physical and chemical properties in addition to graphene. This article briefly reviews a recent progress of the fabrication of GO-based polyaniline, ionic N-substituted copolyaniline and polystyrene nanocomposites. The critical electrorheological characteristics such as flow response and yield stress from rheological measurement, relaxation time and achievable polarizability from dielectric analysis are also analyzed.

  2. Large-Strain Transparent Magnetoactive Polymer Nanocomposites

    NASA Technical Reports Server (NTRS)

    Meador, Michael A.

    2012-01-01

    A document discusses polymer nano - composite superparamagnetic actuators that were prepared by the addition of organically modified superparamagnetic nanoparticles to the polymer matrix. The nanocomposite films exhibited large deformations under a magnetostatic field with a low loading level of 0.1 wt% in a thermoplastic polyurethane elastomer (TPU) matrix. The maximum actuation deformation of the nanocomposite films increased exponentially with increasing nanoparticle concentration. The cyclic deformation actuation of a high-loading magnetic nanocomposite film was examined in a low magnetic field, and it exhibited excellent reproducibility and controllability. Low-loading TPU nanocomposite films (0.1-2 wt%) were transparent to semitransparent in the visible wavelength range, owing to good dispersion of the magnetic nanoparticles. Magnetoactuation phenomena were also demonstrated in a high-modulus, high-temperature polyimide resin with less mechanical deformation.

  3. Polysaccharide-based nanocomposites and their applications

    PubMed Central

    Zheng, Yingying; Monty, Jonathan; Linhardt, Robert J.

    2014-01-01

    Polysaccharide nanocomposites have become increasingly important materials over the past decade. Polysaccharides offer a green alternative to synthetic polymers in the preparation of soft nanomaterials. They have also been used in composites with hard nanomaterials, such as metal nanoparticles and carbon-based nanomaterials. This mini review describes methods for polysaccharide nanocomposite preparation and reviews the various types and diverse applications for these novel materials. PMID:25498200

  4. Carbon nanotube-polymer nanocomposite infrared sensor.

    PubMed

    Pradhan, Basudev; Setyowati, Kristina; Liu, Haiying; Waldeck, David H; Chen, Jian

    2008-04-01

    The infrared photoresponse in the electrical conductivity of single-walled carbon nanotubes (SWNTs) is dramatically enhanced by embedding SWNTs in an electrically and thermally insulating polymer matrix. The conductivity change in a 5 wt % SWNT-polycarbonate nanocomposite is significant (4.26%) and sharp upon infrared illumination in the air at room temperature. While the thermal effect predominates in the infrared photoresponse of a pure SWNT film, the photoeffect predominates in the infrared photoresponse of SWNT-polycarbonate nanocomposites. PMID:18333623

  5. Highly ordered mesoporous silica nanoparticles and their application to DNA separation

    NASA Astrophysics Data System (ADS)

    Lee, Hye Sun; Chang, Jeong Ho

    2008-12-01

    This work describes the innovative development of high throughput human DNA purification process using the molecular self-assembled mesoporous silica nanoparticles. The mesoporous silica nanoparticles were prepared by sol-gel method and the formation of molecular self-assembled monolayers with functional groups was chemically demonstrated. The surface modification of functional groups was performed with aminofunctionallized organic silanes on mesoporous silica nanoparticles and the results of DNA separation was represented with electrophoresis images.

  6. Fe3O4@mSiO2-FA-CuS-PEG nanocomposites for magnetic resonance imaging and targeted chemo-photothermal synergistic therapy of cancer cells.

    PubMed

    Gao, Zhifang; Liu, Xijian; Deng, Guoying; Zhou, Feng; Zhang, Lijuan; Wang, Qian; Lu, Jie

    2016-09-14

    In this work, a new multifunctional nanoplatform (Fe3O4@mSiO2-FA-CuS-PEG nanocomposite) for magnetic resonance imaging (MRI) and targeted chemo-photothermal therapy, was firstly fabricated on the basis of magnetic mesoporous silica nanoparticles (Fe3O4@mSiO2), on which folic acid (FA) was grafted as the targeting reagent, CuS nanocrystals were attached as the photothermal agent, and polyethylene glycol (PEG) was coupled to improve biocompatibility. The characterization results demonstrated that the fabricated Fe3O4@mSiO2-FA-CuS-PEG nanocomposites not only showed strong magnetism and excellent MRI performance, but also had a high doxorubicin (DOX, an anticancer drug) loading capacity (22.1%). The loaded DOX can be sustainably released, which was apt to be controlled by pH adjustment and near infrared (NIR) laser irradiation. More importantly, targeted delivery of the DOX-loaded Fe3O4@mSiO2-FA-CuS-PEG nanocomposites could be accomplished in HeLa cells via the receptor-mediated endocytosis pathway, and this exhibited synergistic effect of chemotherapy and photothermal therapy against HeLa cells under irradiation with a 915 nm laser. Therefore, the fabricated multifunctional Fe3O4@mSiO2-FA-CuS-PEG nanocomposite has a great potential in image-guided therapy of cancers. PMID:27493065

  7. Designing new ferrite/manganite nanocomposites

    NASA Astrophysics Data System (ADS)

    Muscas, G.; Anil Kumar, P.; Barucca, G.; Concas, G.; Varvaro, G.; Mathieu, R.; Peddis, D.

    2016-01-01

    Two kinds of nanocomposites of transition metal oxides were synthesized and investigated. Each nanocomposite comprises nanoparticles of La0.67Ca0.33MnO3 and CoFe2O4 in similar volume fractions, however arranged with different morphologies. The temperature-dependent magnetic and electrical properties of the two systems are found to greatly differ, suggesting different degrees of interaction and coupling of their constituents. This is confirmed by magnetic field-dependent experiments, which reveal contrasted magnetization reversal and magnetoresistance in the systems. We discuss this morphology-physical property relationship, and the possibility to further tune the magnetism and magneto-transport in such nanocomposites.Two kinds of nanocomposites of transition metal oxides were synthesized and investigated. Each nanocomposite comprises nanoparticles of La0.67Ca0.33MnO3 and CoFe2O4 in similar volume fractions, however arranged with different morphologies. The temperature-dependent magnetic and electrical properties of the two systems are found to greatly differ, suggesting different degrees of interaction and coupling of their constituents. This is confirmed by magnetic field-dependent experiments, which reveal contrasted magnetization reversal and magnetoresistance in the systems. We discuss this morphology-physical property relationship, and the possibility to further tune the magnetism and magneto-transport in such nanocomposites. Electronic supplementary information (ESI) available. See DOI: 10.1039/c5nr07572f

  8. Random lasing in a nanocomposite medium

    SciTech Connect

    Smetanin, Sergei N; Basiev, Tasoltan T

    2013-01-31

    The characteristics of a random laser based on a nanocomposite medium consisting of a transparent dielectric and scattering doped nanocrystals are calculated. It is proposed to use ytterbium laser media with a high concentration of active ions as nanocrystals and to use gases, liquids, or solid dielectrics with a refractive index lower than that of nanocrystals as dielectric matrices for nanocrystals. Based on the concept of nonresonant distributed feedback due to the Rayleigh scattering, an expression is obtained for the minimum length of a nanocomposite laser medium at which the random lasing threshold is overcome. Expressions are found for the critical (maximum) and the optimal size of nanocrystals, as well as for the optimal relative refractive index of nanocomposites that corresponds not only to the maximum gain but also to the minimum of the medium threshold length at the optimal size of nanocrystals. It is shown that the optimal relative refractive index of a nanocomposite increases with increasing pump level, but is independent of the other nanocomposite parameters. (nanocomposites)

  9. Introduction of bridging and pendant organic groups into mesoporous alumina materials.

    PubMed

    Grant, Stacy M; Woods, Stephan M; Gericke, Arne; Jaroniec, Mietek

    2011-11-01

    Incorporation of organic functionalities into soft-templated mesoporous alumina was performed via organosilane-assisted evaporation induced self-assembly using aluminum alkoxide precursors and block copolymer templates. This strategy permits one to obtain mesoporous alumina-based materials with tailorable adsorption, surface and structural properties. Isocyanurate, ethane, mercaptopropyl, and ureidopropyl-functionalized mesoporous alumina materials were synthesized with relatively high surface area and large pore volume with uniform and wormhole-like mesopores. The presence of organosilyl groups within these hybrid materials was confirmed by IR or Raman spectroscopy and their concentration was determined by elemental analysis. PMID:21988174

  10. Using mesoporous carbon electrodes for brackish water desalination.

    PubMed

    Zou, Linda; Li, Lixia; Song, Huaihe; Morris, Gayle

    2008-04-01

    Electrosorptive deionisation is an alternative process to remove salt ions from the brackish water. The porous carbon materials are used as electrodes. When charged in low voltage electric fields, they possess a highly charged surface that induces adsorption of salt ions on the surface. This process is reversible, so the adsorbed salt ions can be desorbed and the electrode can be reused. In the study, an ordered mesoporous carbon (OMC) electrode was developed for electrosorptive desalination. The effects of pore arrangement pattern (ordered and random) and pore size distribution (mesopores and micropores) on the desalination performance was investigated by comparing OMC and activated carbon (AC). It were revealed from X-ray diffraction and N(2) sorption measurements that AC has both micropores and mesopores, whereas ordered mesopores are dominant in OMC. Their performance as potential electrodes to remove salt was evaluated by cyclic voltammetry (CV) and galvanostatic charge/discharge tests at a range of electrolyte concentrations and sweep rates. It is deduced that under the same electrochemical condition the specific capacitance values of OMC electrode (i.e. 133 F/g obtained from CV at a sweep rate of 1 mV/s in 0.1M NaCl solution) are larger than those of AC electrode (107 F/g), suggesting that the former has a higher desalting capacity than the latter. Furthermore, the OMC electrode shows a better rate capacity than the AC electrode. In addition, the desalination capacities were quantified by the batch-mode experiment at low voltage of 1.2V in 25 ppm NaCl solution (50 micros/cm conductivity). It was found that the adsorbed ion amounts of OMC and AC electrodes were 11.6 and 4.3 micromol/g, respectively. The excellent electrosorptive desalination performance of OMC electrode might be not only due to the suitable pore size (average of 3.3 nm) for the propagation of the salt ions, but also due to the ordered mesoporous structure that facilitates desorption of the

  11. Morphological Control of Multifunctional Mesoporous Silica Nanomaterials for Catalysis Applications

    SciTech Connect

    Seong Huh

    2004-12-19

    I found an efficient method to control the morphology of the organically monofunctionalized mesoporous silica materials by introducing different types of organoalkoxysilanes in a base-catalyzed co-condensation reaction. The monofunctionalized materials exhibit different particle morphologies relative to the pure MCM-41 material. The concentration dependence of the morphology is a critical factor to determine the final particle shape. A proposed mechanism of the shape evolution is also offered. After understanding the role of organoalkoxysilanes in producing various well-shaped nanomaterials, I also obtained a series of bifunctional mesoporous silica materials with certain particle morphology. A series of bifunctional mesoporous silica nanospheres (MSNs) whose physicochemical properties was investigated via solid state NMR techniques and Cu{sup 2+} adsorption capacity tests, The ratio of two different organic groups inside of mesopores of these MSNs could be fine-tuned. These MSNs serve as a useful model system to study substrate selectivity in catalytic reactions and sorption phenomena. For example, the Cu{sup 2+} adsorption capacity of these materials was dictated by the chemical nature of the mesopores generated by the different organic functional groups. An investigation of the substrate selectivity of the bifunctionalized MSNs in a competitive nitroaldol reaction using an equimolar amount of two competing 4-nitrobenzaldehyde derivatives was performed. Shape-controlled bifunctional MSNs were employed as the catalysts. The properties of the MSNs were investigated using various spectroscopic methods and electron microscopy. The more hydrophobic the surface organic groups are, the higher the ratio of hydrophobic final product. This is the first example to demonstrate the selection of substrate using physicochemical nature of the mesopore surface other than the conventional shape selection in zeolite systems. I also created a cooperative dual catalyst system that is

  12. Morphological control of multifunctionalized mesoporous silica nanomaterials for catalysis applications

    NASA Astrophysics Data System (ADS)

    Huh, Seong

    I found an efficient method to control the morphology of the organically monofunctionalized mesoporous silica materials by introducing different types of organoalkoxysilanes in a base-catalyzed co-condensation reaction. The monofunctionalized materials exhibit different particle morphologies relative to the pure MCM-41 material. The concentration dependence of the morphology is a critical factor to determine the final particle shape. A proposed mechanism of the shape evolution is also offered. After understanding the role of organoalkoxysilanes in producing various well-shaped nanomaterials, I also obtained a series of bifunctional mesoporous silica materials with certain particle morphology. A series of bifunctional mesoporous silica nanospheres (MSNs) whose physicochemical properties was investigated via solid state NMR techniques and Cu 2+ adsorption capacity tests. The ratio of two different organic groups inside of mesopores of these MSNs could be fine-tuned. These MSNs serve as a useful model system to study substrate selectivity in catalytic reactions and sorption phenomena. For example, the Cu2+ adsorption capacity of these materials was dictated by the chemical nature of the mesopores generated by the different organic functional groups. An investigation of the substrate selectivity of the bifunctionalized MSNs in a competitive nitroaldol reaction using an equimolar amount of two competing 4-nitrobenzaldehyde derivatives was performed. Shape-controlled bifunctional MSNs were employed as the catalysts. The properties of the MSNs were investigated using various spectroscopic methods and electron microscopy. The more hydrophobic the surface organic groups are, the higher the ratio of hydrophobic final product. This is the first example to demonstrate the selection of substrate using physicochemical nature of the mesopore surface other than the conventional shape selection in zeolite systems. I also created a cooperative dual catalyst system that is capable of

  13. Infiltrating sulfur in hierarchical architecture MWCNT@meso C core-shell nanocomposites for lithium-sulfur batteries.

    PubMed

    Wang, Deli; Yu, Yingchao; Zhou, Weidong; Chen, Hao; DiSalvo, Francis J; Muller, David A; Abruña, Héctor D

    2013-06-21

    We present hierarchical architecture MWCNT (multi-walled carbon nanotubes)@meso C core-shell nanostructures as a carbon matrix for effective trapping of sulfur/polysulfides as a cathode material for Li-S batteries. The unique structure of MWCNT@meso C core-shell nanocomposites was achieved by using a sol-gel coating method followed by nanocasting. By infiltrating sulfur into the matrix, S/MWCNT@meso C core-shell nanocomposites were achieved. This material exhibited an initial discharge capacity of 1248 mA h g(-1) although it decayed to about 640 mA h g(-1) after 50 cycles. However, this performance is much better than that of S directly deposited on MWCNT (S/MWCNT) which only retained a capacity of 120 mA h g(-1) after 50 cycles. Our composite exhibited excellent rate capability even at a discharge current density of 2 A g(-1). The improvement in electrochemical performance is attributed to the synergetic effect between MWCNT cores, which provide electronic conduction pathways, and the mesoporous carbon shells with a relatively high surface area, which can trap sulfur/polysulfides and provide Li(+) ion pathways. PMID:23661229

  14. Preparation and photocatalytical performance of TiO2:SiO2 nanocomposites produced by the polymeric precursors method.

    PubMed

    Dawson, Margaret; Soares, Gabriela Byzynski; Ribeiro, Caue

    2013-07-01

    Anatase TiO2 is a promising photocatalyst due to its chemical stability, non-toxic characteristics, notable UV light absorption as well as photo-corrosion resistance and oxidative properties. Surface area and TiO2 dispersion quality are important factors that affect photoactivity of TiO2:SiO2 nanocomposites. In order to improve these factors, TiO2 nanoparticles were immobilized on mesoporous silica substrate through the polymeric precursors method, obtaining the nanocomposites in a simple routine. The TiO2 resin was synthesized by the polymeric precursors method and different resin thickness (0.5; 1.0; 2.0; 3.5; 5.0 nm) on silica were synthesized by calcination during 4 hours at 450 degrees C in pH 1.5. The selected pH for immobilization ensured adhesion of TiO2 nanoparticles onto the silica substrate surface. X-Ray Diffraction patterns indicate that all samples were predominantly anatase phase and immobilization improved surface area. Ametryn kinetic evaluation presents better results for SAM 3.5 and SAM 0.5. The results show that difference in TiO2 loading, surface area and crystallinity of samples are factors that influence photocatalytic efficiency. PMID:23901540

  15. Biological performances of poly(ether)urethane silver nanocomposites

    NASA Astrophysics Data System (ADS)

    Hung, Huey-Shan; Hsu, Shan-hui

    2007-11-01

    A series of nanocomposites (PU-Ag) from a polyether-type waterborne polyurethane (PU) incorporated with various amounts (15.1-113 ppm) of silver nanoparticles (approximately 5 nm) were prepared in this study. The surface morphology, biocompatibility, bacterial adhesion and free radical scavenging ability of the nanocomposites were investigated. PU-Ag nanocomposites had a different surface morphology from PU, especially at 30.2 ppm of silver. The latter nanocomposite showed enhanced cellular proliferation and reduced monocyte activation, compared with the original PU or nanocomposites with other Ag content. The nanocomposite also exhibited very low bacterial adhesion. The data obtained from a Ag+-resistant bacterial strain suggested that the release of Ag+ from the nanocomposites may not be the major cause for lower bacterial adhesion on these nanocomposites. Instead, surface morphology accounted for the general improvement of all performances.

  16. Preparation and Properties of Graphene Oxide Modified Nanocomposite Hydrogels

    NASA Astrophysics Data System (ADS)

    Liu, Sihang; Huang, Mei

    2014-08-01

    Nanocomposite hydrogels with graphene oxide as chemical cross-linker were synthesized after graphene oxide being pretreated by methacryloyl chloride. Moreover, the mechanical behavior of nanocomposite hydrogels based on acrylamide (AAm) and graphene oxide (GO) was studied with different compositions. Experimental results of the swollen state properties of the nanocomposite hydrogels indicated that the addition of GO could effectively enhance the strength but lowers the swelling degree of nanocomposite hydrogels.

  17. Shape-Morphing Nanocomposite Origami

    PubMed Central

    2015-01-01

    Nature provides a vast array of solid materials that repeatedly and reversibly transform in shape in response to environmental variations. This property is essential, for example, for new energy-saving technologies, efficient collection of solar radiation, and thermal management. Here we report a similar shape-morphing mechanism using differential swelling of hydrophilic polyelectrolyte multilayer inkjets deposited on an LBL carbon nanotube (CNT) composite. The out-of-plane deflection can be precisely controlled, as predicted by theoretical analysis. We also demonstrate a controlled and stimuli-responsive twisting motion on a spiral-shaped LBL nanocomposite. By mimicking the motions achieved in nature, this method offers new opportunities for the design and fabrication of functional stimuli-responsive shape-morphing nanoscale and microscale structures for a variety of applications. PMID:24689908

  18. Crosslinked Matrix-free Nanocomposites

    NASA Astrophysics Data System (ADS)

    Dach, Benjamin; Rengifo, Hernan; Turro, Nicholas; Koberstein, Jeffrey

    2010-03-01

    Matrix-free polymer-silica nanocomposites are formed by crosslinking polymer coated nanoparticles via the `click' reaction. The `click' reaction is also known as H"uisgen 1, 3-dipolar cycloaddition of terminal alkyne and azide functional groups to give 1, 2, 3-triazoles. Silica nanoparticles are functionalized with alkyne and azide moieties. Heterobifunctional α,φ-trimethylsilane-alkyne,azide-poly(styrene) (TMS-PS-N3) and α,φ-trimethylsilane-alkyne,azide--poly(tert-butyl acrylate) (TMS-PtBA-N3) are then covalently bound to the surfaces of the nanoparticles via the `click' reaction. The bare and modified nanoparticles are analyzed by diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS). The thermal, morphological, and mechanical properties of the systems are investigated by thermogravimetric analysis (TGA), transmission electron microscopy (TEM), and dynamic rheology, respectively. .

  19. Molecular Theories of Polymer Nanocomposites

    SciTech Connect

    Hall, Lisa M; Jayaraman, Arthi; Schweizer, Kenneth S

    2010-01-01

    Significant progress towards the development of microscopic predictive theories of the equilibrium structure, polymer-mediated interactions, and phase behavior of polymer nanocomposites has been made recently based on liquid state integral equation, density functional, and self-consistent mean field approaches. The basics of these three theoretical frameworks are summarized, and selected highlights of their recent applications discussed for spherical, nonspherical, and polymer-grafted nanoparticles dissolved in athermal and adsorbing concentrated solutions and homopolymer melts. The role of nanoparticle size, volume fraction, and interfacial cohesive interactions is emphasized, especially with regards to their influence on filler dispersion and spatial ordering via entropic depletion attraction, polymer adsorption-mediated steric stabilization, and local bridging of nanoparticles. Some of the many remaining theoretical challenges and open fundamental questions are summarized.

  20. Shape-morphing nanocomposite origami.

    PubMed

    Andres, Christine M; Zhu, Jian; Shyu, Terry; Flynn, Connor; Kotov, Nicholas A

    2014-05-20

    Nature provides a vast array of solid materials that repeatedly and reversibly transform in shape in response to environmental variations. This property is essential, for example, for new energy-saving technologies, efficient collection of solar radiation, and thermal management. Here we report a similar shape-morphing mechanism using differential swelling of hydrophilic polyelectrolyte multilayer inkjets deposited on an LBL carbon nanotube (CNT) composite. The out-of-plane deflection can be precisely controlled, as predicted by theoretical analysis. We also demonstrate a controlled and stimuli-responsive twisting motion on a spiral-shaped LBL nanocomposite. By mimicking the motions achieved in nature, this method offers new opportunities for the design and fabrication of functional stimuli-responsive shape-morphing nanoscale and microscale structures for a variety of applications. PMID:24689908

  1. MULTISCALE MODELING OF POLYMER NANOCOMPOSITES

    SciTech Connect

    Maiti, A

    2007-07-16

    Polymer Nanocomposites are an important class of nanomaterials with potential applications including but not limited to structural and cushion materials, electromagnetic and heat shields, conducting plastics, sensors, and catalysts for various chemical and bio processes. Success in most such applications hinges on molecular-level control of structure and assembly, and a deep understanding of how the overall morphology of various components and the interfaces between them affect the composite properties at the macroscale. The length and time-scales associated with such assemblies are prohibitively large for a full atomistic modeling. Instead we adopt a multiscale methodology in which atomic-level interactions between different components of a composite are incorporated into a coarse-grained simulation of the mesoscale morphology, which is then represented on a numerical grid and the macroscopic properties computed using a finite-elements method.

  2. Comparing Nanofillers in Polylactide Nanocomposites

    NASA Astrophysics Data System (ADS)

    Kontou, Evangelia; Niaounakis, Michael

    2010-06-01

    The present study compares the effects of two different types of nanosized fillers (silica and montmorillonite) at three different weight fractions as well their mixtures on the thermomechanical properties of polylactide (PLA). The role of aggregation and interphase was investigated with several experimental techniques including DSC, WAXS, SEM and tensile measurements. The experimental results clearly suggest that silica and montmorilonite have different reinforcing and toughnening effects on PLA, while the combination of the two different nanofillers seems to have a detrimental effect on the total interphase volume of the material. Four micromechanics models (Mori-Tanaka, Chen, Taya-Chu and Odegard), describing the Young's modulus of the nanocomposites, were used to study the different matrix-nanofiller interactions.

  3. Graphite nanoreinforcements in polymer nanocomposites

    NASA Astrophysics Data System (ADS)

    Fukushima, Hiroyuki

    Nanocomposites composed of polymer matrices with clay reinforcements of less than 100 nm in size, are being considered for applications such as interior and exterior accessories for automobiles, structural components for portable electronic devices, and films for food packaging. While most nanocomposite research has focused on exfoliated clay platelets, the same nanoreinforcement concept can be applied to another layered material, graphite, to produce nanoplatelets and nanocomposites. Graphite is the stiffest material found in nature (Young's Modulus = 1060 GPa), having a modulus several times that of clay, but also with excellent electrical and thermal conductivity. The key to utilizing graphite as a platelet nanoreinforcement is in the ability to exfoliate this material. Also, if the appropriate surface treatment can be found for graphite, its exfoliation and dispersion in a polymer matrix will result in a composite with not only excellent mechanical properties but electrical properties as well, opening up many new structural applications as well as non-structural ones where electromagnetic shielding and high thermal conductivity are requirements. In this research, a new process to fabricate exfoliated nano-scale graphite platelets was established (Patent pending). The size of the resulted graphite platelets was less than 1 um in diameter and 10 nm in thickness, and the surface area of the material was around 100 m2/g. The reduction of size showed positive effect on mechanical properties of composites because of the increased edge area and more functional groups attached with it. Also various surface treatment techniques were applied to the graphite nanoplatelets to improve the surface condition. As a result, acrylamide grafting treatment was found to enhance the dispersion and adhesion of graphite flakes in epoxy matrices. The resulted composites showed better mechanical properties than those with commercially available carbon fibers, vapor grown carbon fibers

  4. Catalytic Mesoporous Janus Nanomotors for Active Cargo Delivery

    PubMed Central

    2015-01-01

    We report on the synergy between catalytic propulsion and mesoporous silica nanoparticles (MSNPs) for the design of Janus nanomotors as active cargo delivery systems with sizes <100 nm (40, 65, and 90 nm). The Janus asymmetry of the nanomotors is given by electron beam (e-beam) deposition of a very thin platinum (2 nm) layer on MSNPs. The chemically powered Janus nanomotors present active diffusion at low H2O2 fuel concentration (i.e., <3 wt %). Their apparent diffusion coefficient is enhanced up to 100% compared to their Brownian motion. Due to their mesoporous architecture and small dimensions, they can load cargo molecules in large quantity and serve as active nanocarriers for directed cargo delivery on a chip. PMID:25844893

  5. Chemoradiotherapeutic wrinkled mesoporous silica nanoparticles for use in cancer therapy

    SciTech Connect

    Munaweera, Imalka; Balkus, Kenneth J. Jr. E-mail: Anthony.DiPasqua@unthsc.edu; Koneru, Bhuvaneswari; Shi, Yi; Di Pasqua, Anthony J. E-mail: Anthony.DiPasqua@unthsc.edu

    2014-11-01

    Over the last decade, the development and application of nanotechnology in cancer detection, diagnosis, and therapy have been widely reported. Engineering of vehicles for the simultaneous delivery of chemo- and radiotherapeutics increases the effectiveness of the therapy and reduces the dosage of each individual drug required to produce an observable therapeutic response. We here developed a novel chemoradiotherapeutic 1,2-dioleoyl-sn-glycero-3-phosphocholine lipid coated/uncoated platinum drug loaded, holmium-containing, wrinkled mesoporous silica nanoparticle. The materials were characterized with TEM, FTIR, {sup 1}H NMR, energy dispersive x-ray, inductively coupled plasma-mass spectrometry, and zeta potential measurements. In vitro platinum drug release from both lipid coated and uncoated chemoradiotherapeutic wrinkled mesoporous silica are reported. Various kinetic models were used to analyze the release kinetics. The radioactivity of the chemoradiotherapeutic nanocarriers was measured after neutron-activation.

  6. Preparation and characterization of well ordered mesoporous diopside nanobiomaterial.

    PubMed

    Wei, Jie; Lu, Jingxiong; Yan, Yonggang; Li, Hong; Ma, Jian; Wu, Xiaohui; Dai, Chenglong; Liu, Changsheng

    2011-12-01

    Well ordered mesoporous diopside (OMD) nanobiomaterial was synthesized by a sol-gel process. The in vitro bioactivity of the OMD was evaluated by investigating the apatite-forming ability in simulated body fluid (SBF), and the hemostatic activity of the OMD was determined by measuring the activated partial thromboplastin time (APTT) and prothrombin time (PT) in vitro. The results suggested that the OMD exhibited excellent in vitro bioactivity, with surface apatite formation for OMD exceeding that of non-mesoporous diopside (n-MD) at 7 days. Moreover, the OMD with high surface area possessed good hemostatic property because it could absorb a large number of water from the blood. In conclusion, the prepared OMD had excellent bioactivity and hemostatic activity, which can not only be applied as bone repair biomaterial for bone regeneration, but also as hemostatic agent for surgery hemostasis. PMID:22408987

  7. In Situ Loading of Drugs into Mesoporous Silica SBA-15.

    PubMed

    Wan, Mi Mi; Li, Yan Yan; Yang, Tian; Zhang, Tao; Sun, Xiao Dan; Zhu, Jian Hua

    2016-04-25

    In a new strategy for loading drugs into mesoporous silica, a hydrophilic (heparin) or hydrophobic drug (ibuprofen) is encapsulated directly in a one-pot synthesis by evaporation-induced self-assembly. In situ drug loading significantly cuts down the preparation time and dramatically increases the loaded amount and released fraction of the drug, and appropriate drug additives favor a mesoporous structure of the vessels. Drug loading was verified by FTIR spectroscopy and release tests, which revealed much longer release with a larger amount of heparin or ibuprofen compared to postloaded SBA-15. Besides, the in vitro anticoagulation properties of the released heparin and the biocompatibility of the vessels were carefully assessed, including activated partial thromboplastin time, thrombin time, hemolysis, platelet adhesion experiments, and the morphologies of red blood cells. A concept of new drug-release agents with soft core and hard shell is proposed and offers guidance for the design of novel drug-delivery systems. PMID:26999658

  8. Chemoradiotherapeutic wrinkled mesoporous silica nanoparticles for use in cancer therapy

    NASA Astrophysics Data System (ADS)

    Munaweera, Imalka; Koneru, Bhuvaneswari; Shi, Yi; Di Pasqua, Anthony J.; Balkus, Kenneth J., Jr.

    2014-11-01

    Over the last decade, the development and application of nanotechnology in cancer detection, diagnosis, and therapy have been widely reported. Engineering of vehicles for the simultaneous delivery of chemo- and radiotherapeutics increases the effectiveness of the therapy and reduces the dosage of each individual drug required to produce an observable therapeutic response. We here developed a novel chemoradiotherapeutic 1,2-dioleoyl-sn-glycero-3-phosphocholine lipid coated/uncoated platinum drug loaded, holmium-containing, wrinkled mesoporous silica nanoparticle. The materials were characterized with TEM, FTIR, 1H NMR, energy dispersive x-ray, inductively coupled plasma-mass spectrometry, and zeta potential measurements. In vitro platinum drug release from both lipid coated and uncoated chemoradiotherapeutic wrinkled mesoporous silica are reported. Various kinetic models were used to analyze the release kinetics. The radioactivity of the chemoradiotherapeutic nanocarriers was measured after neutron-activation.

  9. Oriented mesoporous nanopyramids as versatile plasmon-enhanced interfaces.

    PubMed

    Kong, Biao; Tang, Jing; Selomulya, Cordelia; Li, Wei; Wei, Jing; Fang, Yin; Wang, Yongcheng; Zheng, Gengfeng; Zhao, Dongyuan

    2014-05-14

    We developed a facile interfacial oriented growth and self-assembly process to fabricate three-dimensional (3D) aligned mesoporous iron oxide nanopyramid arrays (NPAs). The unique NPAs possess a 3D mesostructure with multiple features, including high surface area (~175 m(2)/g), large pore size (~20 nm), excellent flexibility (bent over 150 times), and scalability at the foot scale for practical applications. More importantly, these NPAs structures enable versatile enhancement of localized surface plasmon resonance and photoelectrochemical conversion. The integration of plasmonic gold with 3D NPAs remarkably improves the performance of photoelectrochemical conversion, leading to ~6- and 83-fold increases of the photocurrent under simulated solar and visible-light illumination, respectively. The fabrication and investigation of NPAs provide a new paradigm for preparing unconventional mesoporous oriented thin films and further suggest a new strategy for designing plasmonic metal/semiconductor systems for effective solar energy harvesting. PMID:24786963

  10. Synthesis and characterization of acidic mesoporous borosilicate thin films.

    PubMed

    Xiu, Tongping; Liu, Qian; Wang, Jiacheng

    2009-02-01

    Work on the synthesis and characterization of acidic wormhole-like ordered mesoporous borosilicate thin films (MBSTFs) on silicon wafers is described in this paper. The MBSTFs coated by the dip-coating method were prepared through an evaporation-induced self-assembly (EISA) process using nonionic block copolymers as structure-directing agents. Fourier transform infrared (FT-IR) spectroscopy confirmed the formation of borosiloxane bonds (Si-O-B). High-resolution transmission electron microscopy (HRTEM) and N2 sorption evidenced a wormhole-like mesoporous structure in the MBSTFs obtained. Scanning electron microscopy (SEM) images of the cross sections and surfaces of the samples showed that MBSTFs on silicon wafers were continuous, homogeneous and did not crack. The acidic properties of the MBSTFs were characterized by FT-IR spectra of chemisorbed pyridine. The MBSTFs thus prepared may find their future applications in many fields including chemical sensors, catalysis, optical coating, molecule separation, etc. PMID:19441565

  11. Mesoporous Silica Nanoparticles and Films for Cargo Delivery

    NASA Astrophysics Data System (ADS)

    Guardado Alvarez, Tania Maria

    Mesoporous silica materials are well known materials that can range from films to nanoparticles. Mesoporous silica nanoparticles (MSNs) and mesoporous silica films have been of increasing interest among the scientific community for its use in cargo delivery. Silica provides ease of functionalization, a robust support and biocompatibility. Several methods have been used in order to give the mesoporous silica nanomaterials different qualities that render them a useful material with different characteristics. Among these methods is surface modification by taking advantage of the OH groups on the surface. When a molecule attached to the surface can act as a molecular machine it transforms the nanomaterial to act as delivery system that can be activated upon command. The work covered in this thesis focuses on the development and synthesis of different mesoporous silica materials for the purpose of trapping and releasing cargo molecules. Chapter 2 focuses in the photoactivation of "snap-top" stoppers over the pore openings of mesoporous silica nanoparticles that releases intact cargo molecules from the pores. The on-command release can be stimulated by either one UV photon or two coherent near-IR photons. Two-photon activation is particularly desirable for use in biological systems because it enables good tissue penetration and precise spatial control. Chapter 3 focuses on the design and synthesis of a nano-container consisting of mesoporous silica nanoparticles with the pore openings covered by "snap-top" caps that are opened by near-IR light. A photo transducer molecule that is a reducing agent in an excited electronic state is covalently attached to the system. Near IR two-photon excitation causes intermolecular electron transfer that reduces a disulfide bond holding the cap in place, thus allowing the cargo molecules to escape. The operation of the "snap-top" release mechanism by both one- and two photon is described. This system presents a proof of concept of a near

  12. Impact of Surface Chemistry on Copper Deposition in Mesoporous Silicon.

    PubMed

    Darwich, Walid; Garron, Anthony; Bockowski, Piotr; Santini, Catherine; Gaillard, Frédéric; Haumesser, Paul-Henri

    2016-08-01

    An easy, efficient, and safe process is developed to metallize mesoporous silicon (PSi) with Cu from the decomposition of a solution of mesitylcopper (CuMes) in an imidazolium-based ionic liquid (IL), [C1C4Im][NTf2]. The impregnation of a solution of CuMes in IL affords the deposition of metallic islands not only on the surface but also deep within the pores of a mesoporous Si layer with small pores below 10 nm. Therefore, this process is well suited to efficiently and completely metallize PSi layers. An in-depth mechanistic study shows that metal deposition is due to the reduction of CuMes by surface silane groups rather than by Si oxidation as observed in aqueous or water-containing media. This could open a new route to the chemical metallization of PSi by less-noble metals difficult to attain by a conventional displacement reaction. PMID:27368422

  13. Adsorption of benzene, cyclohexane and hexane on ordered mesoporous carbon.

    PubMed

    Wang, Gang; Dou, Baojuan; Zhang, Zhongshen; Wang, Junhui; Liu, Haier; Hao, Zhengping

    2015-04-01

    Ordered mesoporous carbon (OMC) with high specific surface area and large pore volume was synthesized and tested for use as an adsorbent for volatile organic compound (VOC) disposal. Benzene, cyclohexane and hexane were selected as typical adsorbates due to their different molecular sizes and extensive utilization in industrial processes. In spite of their structural differences, high adsorption amounts were achieved for all three adsorbates, as the pore size of OMC is large enough for the access of these VOCs. In addition, the unusual bimodal-like pore size distribution gives the adsorbates a higher diffusion rate compared with conventional adsorbents such as activated carbon and carbon molecular sieve. Kinetic analysis suggests that the adsorption barriers mainly originated from the difficulty of VOC vapor molecules entering the pore channels of adsorbents. Therefore, its superior adsorption ability toward VOCs, together with a high diffusion rate, makes the ordered mesoporous carbon a promising potential adsorbent for VOC disposal. PMID:25872710

  14. Catalytic conversion of cellulose over mesoporous Y zeolite.

    PubMed

    Park, Young-Kwon; Jun, Bo Ram; Park, Sung Hoon; Jeon, Jong-Ki; Lee, See Hoon; Kim, Seong-Soo; Jeong, Kwang-Eun

    2014-07-01

    Mesoporous Y zeolite (Meso-Y) was applied, for the first time, to the catalytic pyrolysis of cellulose which is a major constituent of lignocellulosic biomass, to produce high-quality bio-oil. A representative mesoporous catalyst Al-MCM-41 was also used to compare its catalytic activity with that of Meso-Y. Pyrolysis-gas chromatography/mass spectrometry was used for the experiments. Meso-Y, with higher acidity, led to larger yields of aromatics and furans with high value-added than Al-MCM-41, resulting in the production of bio-oil with higher quality. The effect of temperature on the catalytic pyrolysis was not significant within the range of 400-500 degrees C. When the Meso-Y to cellulose ratio was increased from 1/1 via 2/1 to 3/1, the deoxygenation efficiency increased, leading to increased yield of aromatics. PMID:24757989

  15. A series of highly stable mesoporous metalloporphyrin Fe-MOFs.

    PubMed

    Wang, Kecheng; Feng, Dawei; Liu, Tian-Fu; Su, Jie; Yuan, Shuai; Chen, Ying-Pin; Bosch, Mathieu; Zou, Xiaodong; Zhou, Hong-Cai

    2014-10-01

    A series of mesoporous metalloporphyrin Fe-MOFs, namely PCN-600(M) (M = Mn, Fe, Co, Ni, Cu), have been synthesized using the preassembled [Fe3O(OOCCH3)6] building block. PCN-600 exhibits a one-dimensional channel as large as 3.1 nm and the highest experimental pore volume of 1.80 cm(3)g(-1) among all the reported porphyrinic MOFs. It also shows very high stability in aqueous solutions with pH values ranging from 2-11 and is to our knowledge the only mesoporous porphyrinic MOF stable under basic aqueous conditions. PCN-600(Fe) has been demonstrated as an effective peroxidase mimic to catalyze the co-oxidation reaction. PMID:25208035

  16. Flash freezing route to mesoporous polymer nanofibre networks.

    PubMed

    Samitsu, Sadaki; Zhang, Rui; Peng, Xinsheng; Krishnan, Mohan Raj; Fujii, Yoshihisa; Ichinose, Izumi

    2013-01-01

    There are increasing requirements worldwide for advanced separation materials with applications in environmental protection processes. Various mesoporous polymeric materials have been developed and they are considered as potential candidates. It is still challenging, however, to develop economically viable and durable separation materials from low-cost, mass-produced materials. Here we report the fabrication of a nanofibrous network structure from common polymers, based on a microphase separation technique from frozen polymer solutions. The resulting polymer nanofibre networks exhibit large free surface areas, exceeding 300 m(2) g(-1), as well as small pore radii as low as 1.9 nm. These mesoporous polymer materials are able to rapidly adsorb and desorb a large amount of carbon dioxide and are also capable of condensing organic vapours. Furthermore, the nanofibres made of engineering plastics with high glass transition temperatures over 200 °C exhibit surprisingly high, temperature-dependent adsorption of organic solvents from aqueous solution. PMID:24145702

  17. Mesoporous silica nanoparticles for bioadsorption, enzyme immobilisation, and delivery carriers

    NASA Astrophysics Data System (ADS)

    Popat, Amirali; Hartono, Sandy Budi; Stahr, Frances; Liu, Jian; Qiao, Shi Zhang; Qing (Max) Lu, Gao

    2011-07-01

    Mesoporous silica nanoparticles (MSNs) provide a non-invasive and biocompatible delivery platform for a broad range of applications in therapeutics, pharmaceuticals and diagnosis. The creation of smart, stimuli-responsive systems that respond to subtle changes in the local cellular environment are likely to yield long term solutions to many of the current drug/gene/DNA/RNA delivery problems. In addition, MSNs have proven to be promising supports for enzyme immobilisation, enabling the enzymes to retain their activity, affording them greater potential for wide applications in biocatalysis and energy. This review provides a comprehensive summary of the advances made in the last decade and a future outlook on possible applications of MSNs as nanocontainers for storage and delivery of biomolecules. We discuss some of the important factors affecting the adsorption and release of biomolecules in MSNs and review of the cytotoxicity aspects of such nanomaterials. The review also highlights some promising work on enzyme immobilisation using mesoporous silica nanoparticles.

  18. Natural dye -sensitized mesoporous ZnO solar cell

    NASA Astrophysics Data System (ADS)

    Wu, Qishuang; Shen, Yue; Wu, Guizhi; Li, Linyu; Cao, Meng; Gu, Feng

    2010-10-01

    Natural dye-sensitized solar cells (N-DSSCs) were assembled using chlorophyll sensitized mesoporous ZnO (based on FTO) as the photoanode and platinum plate as the cathode. The natural dyes (chlorophyll) were extracted from spinach by simple procedure. The absorption spectrum and fluorescence spectrum of chlorophyll were studied. Mesoporous ZnO (m-ZnO) applied to the N-DSSCs was synthesized through hydrothermal method. The structures and morphologies were characterized by X-ray Diffraction (XRD) and diffuse reflection. The results indicated that the samples had an average pore size of 17 nm and the m-ZnO was hexagonal wurtzite structure. The performances of the N-DSSCs were investigated under AM 1.5G illumination. The Voc of the N-DSSCs was about 480mv, and the Isc was about 470μA. The performance of the N-DSSCs could be further improved by adjusting its structure.

  19. Natural dye -sensitized mesoporous ZnO solar cell

    NASA Astrophysics Data System (ADS)

    Wu, Qishuang; Shen, Yue; Wu, Guizhi; Li, Linyu; Cao, Meng; Gu, Feng

    2011-02-01

    Natural dye-sensitized solar cells (N-DSSCs) were assembled using chlorophyll sensitized mesoporous ZnO (based on FTO) as the photoanode and platinum plate as the cathode. The natural dyes (chlorophyll) were extracted from spinach by simple procedure. The absorption spectrum and fluorescence spectrum of chlorophyll were studied. Mesoporous ZnO (m-ZnO) applied to the N-DSSCs was synthesized through hydrothermal method. The structures and morphologies were characterized by X-ray Diffraction (XRD) and diffuse reflection. The results indicated that the samples had an average pore size of 17 nm and the m-ZnO was hexagonal wurtzite structure. The performances of the N-DSSCs were investigated under AM 1.5G illumination. The Voc of the N-DSSCs was about 480mv, and the Isc was about 470μA. The performance of the N-DSSCs could be further improved by adjusting its structure.

  20. Catalytic mesoporous Janus nanomotors for active cargo delivery.

    PubMed

    Ma, Xing; Hahn, Kersten; Sanchez, Samuel

    2015-04-22

    We report on the synergy between catalytic propulsion and mesoporous silica nanoparticles (MSNPs) for the design of Janus nanomotors as active cargo delivery systems with sizes <100 nm (40, 65, and 90 nm). The Janus asymmetry of the nanomotors is given by electron beam (e-beam) deposition of a very thin platinum (2 nm) layer on MSNPs. The chemically powered Janus nanomotors present active diffusion at low H2O2 fuel concentration (i.e., <3 wt %). Their apparent diffusion coefficient is enhanced up to 100% compared to their Brownian motion. Due to their mesoporous architecture and small dimensions, they can load cargo molecules in large quantity and serve as active nanocarriers for directed cargo delivery on a chip. PMID:25844893

  1. Fluorescent Functionalized Mesoporous Silica for Radioactive Material Extraction

    SciTech Connect

    Li, Juan; Zhu, Kake; Shang, Jianying; Wang, Donghai; Nie, Zimin; Guo, Ruisong; Liu, Chongxuan; Wang, Zheming; Li, Xiaolin; Liu, Jun

    2012-08-01

    Mesoporous silica with covalently bound salicylic acid molecules incorporated in the structure was synthesized with a one-pot, co-condensation reaction at room temperature. The as-synthesized material has a large surface area, uniform particle size, and an ordered pore structure as determined by characterization with transmission electron microscopy, thermal gravimetric analysis, and infrared spectra, etc. Using the strong fluorescence and metal coordination capability of salicylic acid, functionalized mesoporous silica (FMS) was developed to track and extract radionuclide contaminants, such as uranyl [U(VI)] ions encountered in subsurface environments. Adsorption measurements showed a strong affinity of the FMS toward U(VI) with a Kd value of 105 mL/g, which is four orders of magnitude higher than the adsorption of U(VI) onto most of the sediments in natural environments. The new materials have a potential for synergistic environmental monitoring and remediation of the radionuclide U(VI) from contaminated subsurface environments.

  2. Preparation and photoluminescence study of mesoporous indium hydroxide nanorods

    SciTech Connect

    Li, Changyu; Lian, Suoyuan; Liu, Yang; Liu, Shouxin; Kang, Zhenhui

    2010-02-15

    Mesoporous indium hydroxide nanorods were successfully synthesized by a mild one-step one-pot method. The obtained samples were characterized by X-ray diffraction, transmission electron microscopy with selected area electron diffraction, N{sub 2} adsorption, ultraviolet-visible absorption and photoluminescence, respectively. Transmission electron microscopy showed that there were some pores in the samples, which were mainly composed of rod-like shapes with length of 300 nm and diameter of 90 nm. N{sub 2} adsorption/desorption measurements confirmed that the prepared powder was mesoporous with average pore diameter of 3.1 nm. The ultraviolet-visible absorption spectroscopy analysis indicated that the band gap energy of the samples was 5.15 eV. Photoluminescence spectrum showed that there were two strong emissions under ultraviolet light irradiation. The growth mechanism of indium hydroxide nanorods and the role of cetyltrimethyl ammonium bromide were also discussed.

  3. Functionalized mesoporous silica materials for molsidomine adsorption: Thermodynamic study

    SciTech Connect

    Alyoshina, Nonna A.; Parfenyuk, Elena V.

    2013-09-15

    A series of unmodified and organically modified mesoporous silica materials was prepared. The unmodified mesoporous silica was synthesized via sol–gel synthesis in the presence of D-glucose as pore-forming agent. The functionalized by phenyl, aminopropyl and mercaptopropyl groups silica materials were prepared via grafting. The fabricated adsorbent materials were characterized by Fourier transform infrared spectroscopy (FTIR) analysis, N{sub 2} adsorption/desorption and elemental analysis methods. Then their adsorption properties for mesoionic dug molsidomine were investigated at 290–313 K and physiological pH value. Thermodynamic parameters of molsidomine adsorption on the synthesized materials have been calculated. The obtained results showed that the adsorption process of molsidomine on the phenyl modified silica is the most quantitatively and energetically favorable. The unmodified and mercaptopropyl modified silica materials exhibit significantly higher adsorption capacities and energies for molsidomine than the aminopropyl modified sample. The effects are discussed from the viewpoint of nature of specific interactions responsible for the adsorption. - Graphical abstract: Comparative analysis of the thermodynamic characteristics of molsidomine adsorption showed that the adsorption process on mesoporous silica materials is controlled by chemical nature of surface functional groups. Molsidomine adsorption on the phenyl modified silica is the most quantitatively and energetically favorable. Taking into account ambiguous nature of mesoionic compounds, it was found that molsidomine is rather aromatic than dipolar. Display Omitted - Highlights: • Unmodified and organically modified mesoporous silica materials were prepared. • Molsidomine adsorption on the silica materials was studied. • Phenyl modified silica shows the highest adsorption capacity and favorable energy. • Molsidomine exhibits the lowest affinity to aminopropyl modified silica.

  4. Electronic Parameters of Mesoporous Silicon Upon Adsorption of Plant Viruses

    NASA Astrophysics Data System (ADS)

    Vashpanov, Yuriy; Son, Jung-Young; Kwack, Kae-Dal; Shin, Seung-Jung

    2008-06-01

    Changes in the electronic parameters of mesoporous silicon upon adsorption of nematodetransmitted polyhedral (NEPO) viruses of plant [tomato ringspot virus (TORSV), grapevine virus A (GVA), and grapevine fan leaf virus (GFLV)] measured at room temperature are investigated. The adsorption of these viruses affected essentially on the electronic characteristic of the porous material. The measurement of the electronic characteristics of porous silicon can be applied to the creation of detectors for the presence of viruses in a given environment.

  5. Sonochemical fabrication of fluorinated mesoporous titanium dioxide microspheres

    SciTech Connect

    Yu Changlin; Yu, Jimmy C.; Chan Mui

    2009-05-15

    A sonochemical-hydrothermal method for preparing fluorinated mesoporous TiO{sub 2} microspheres was developed. Formation of mesoporous TiO{sub 2} and doping of fluorine was achieved by sonication and then hydrothermal treatment of a solution containing titanium isopropoxide, template, and sodium fluoride. The as-synthesized TiO{sub 2} microspheres were characterized by X-ray diffraction (XRD), Fourier translation infrared spectroscopy (FT-IR), X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM), transmission electron microscopy (TEM), energy-dispersive X-ray (EDX) spectroscopy, photoluminescence spectroscopy (PL), and BET surface areas. The P123 template was removed completely during the hydrothermal and washing steps, which was different from the conventional calcination treatment. The as- synthesized TiO{sub 2} microspheres had good crystallinity and high stability. Results from the photocatalytic degradation of methylene blue (MB) showed that fluorination could remarkably improve the photocatalytic activity of titanium dioxide. - Graphical abstract: A novel method for preparing fluorinated mesoporous TiO{sub 2} microspheres was developed by a combined ultrasonic and hydrothermal treatment. The fluorinated TiO{sub 2} microspheres show high crystallinity, stability and enhanced photocatalytic activity.

  6. Aerosol-spray diverse mesoporous metal oxides from metal nitrates

    PubMed Central

    Kuai, Long; Wang, Junxin; Ming, Tian; Fang, Caihong; Sun, Zhenhua; Geng, Baoyou; Wang, Jianfang

    2015-01-01

    Transition metal oxides are widely used in solar cells, batteries, transistors, memories, transparent conductive electrodes, photocatalysts, gas sensors, supercapacitors, and smart windows. In many of these applications, large surface areas and pore volumes can enhance molecular adsorption, facilitate ion transfer, and increase interfacial areas; the formation of complex oxides (mixed, doped, multimetallic oxides and oxide-based hybrids) can alter electronic band structures, modify/enhance charge carrier concentrations/separation, and introduce desired functionalities. A general synthetic approach to diverse mesoporous metal oxides is therefore very attractive. Here we describe a powerful aerosol-spray method for synthesizing various mesoporous metal oxides from low-cost nitrate salts. During spray, thermal heating of precursor droplets drives solvent evaporation and induces surfactant-directed formation of mesostructures, nitrate decomposition and oxide cross-linking. Thirteen types of monometallic oxides and four groups of complex ones are successfully produced, with mesoporous iron oxide microspheres demonstrated for photocatalytic oxygen evolution and gas sensing with superior performances. PMID:25897988

  7. Synthesis and characterization of nanocrystalline and mesoporous zeolites

    NASA Astrophysics Data System (ADS)

    Petushkov, Anton

    2011-12-01

    Mesoporous aggregates of nanocrystalline zeolites with MFI and BEA frameworks have been synthesized using a one-pot and single structure directing agent. The effect of different reaction conditions, such as temperature, time, pH and water content, on the particle size, surface area and mesopore volume has been studied. Nanocrystalline and mesoporous ZSM-5, beta and Y zeolites were modified with different transition metals and the resulting single- and double metal containing catalyst materials were characterized. Nanocrystalline Silicalite-1 zeolite samples with varying particle size were functionalized with different organosilane groups and the cytotoxic activity of the zeolite nanocrystals was studied as a function of particle size, concentration, organic functional group type, as well as the type of cell line. Framework stability of nanocrystalline NaY zeolite was tested under different pH conditions. The synthesized zeolites used in this work were characterized using a variety of physico-chemical methods, including powder X-ray diffraction, Solid State NMR, nitrogen sorption, electron microscopy, Inductively Coupled Plasma -- Optical Emission Spectroscopy and X-ray Photoelectron Spectroscopy.

  8. Capacity of mesoporous bioactive glass nanoparticles to deliver therapeutic molecules

    NASA Astrophysics Data System (ADS)

    El-Fiqi, Ahmed; Kim, Tae-Hyun; Kim, Meeju; Eltohamy, Mohamed; Won, Jong-Eun; Lee, Eun-Jung; Kim, Hae-Won

    2012-11-01

    Inorganic bioactive nanomaterials are attractive for hard tissue regeneration, including nanocomponents for bone replacement composites and nanovehicles for delivering therapeutics. Bioactive glass nanoparticles (BGn) have recently gained potential usefulness as bone and tooth regeneratives. Here we demonstrate the capacity of the BGn with mesopores to load and deliver therapeutic molecules (drugs and particularly genes). Spherical BGn with sizes of 80-90 nm were produced to obtain 3-5 nm sized mesopores through a sono-reacted sol-gel process. A simulated body fluid test of the mesoporous BGn confirmed their excellent apatite forming ability and the cellular toxicity study demonstrated their good cell viability up to 100 μg ml-1. Small molecules like chemical drug (Na-ampicillin) and gene (small interfering RNA; siRNA) were introduced as model drugs considering the mesopore size of the nanoparticles. Moreover, amine-functionalization allowed switchable surface charge property of the BGn (from -20-30 mV to +20-30 mV). Loading of ampicillin or siRNA saturated within a few hours (~2 h) and reflected the mesopore structure. While the ampicillin released relatively rapidly (~12 h), the siRNA continued to release up to 3 days with almost zero-order kinetics. The siRNA-nanoparticles were easily taken up by the cells, with a transfection efficiency as high as ~80%. The silencing effect of siRNA delivered from the BGn, as examined by using bcl-2 model gene, showed dramatic down-regulation (~15% of control), suggesting the potential use of BGn as a new class of nanovehicles for genes. This, in conjunction with other attractive properties, including size- and mesopore-related high surface area and pore volume, tunable surface chemistry, apatite-forming ability, good cell viability and the possible ion-related stimulatory effects, will potentiate the usefulness of the BGn in hard tissue regeneration.Inorganic bioactive nanomaterials are attractive for hard tissue regeneration

  9. Rapid removal of bisphenol A on highly ordered mesoporous carbon.

    PubMed

    Sui, Qian; Huang, Jun; Liu, Yousong; Chang, Xiaofeng; Ji, Guangbin; Deng, Shubo; Xie, Tao; Yu, Gang

    2011-01-01

    Bisphenol A (BPA) is of global concern due to its disruption of endocrine systems and ubiquity in the aquatic environment. It is important, therefore, that efforts are made to remove it from the aqueous phase. A novel adsorbent, mesoporous carbon CMK-3, prepared from hexagonal SBA-15 mesoporous silica was studied for BPA removal from aqueous phase, and compared with conventional powdered activated carbon (PAC). Characterization of CMK-3 by transmission electron microscopy (TEM), X-ray diffraction, and nitrogen adsorption indicated that prepared CMK-3 had an ordered mesoporous structure with a high specific surface area of 920 m2/g and a pore-size of about 4.9 nm. The adsorption of BPA on CMK-3 followed a pseudo second-order kinetic model. The kinetic constant was 0.00049 g/(mg x min), much higher than the adsorption of BPA on PAC. The adsorption isotherm fitted slightly better with the Freundlich model than the Langmuir model, and adsorption capacity decreased as temperature increased from 10 to 40 degrees C. No significant influence of pH on adsorption was observed at pH 3 to 9; however, adsorption capacity decreased dramatically from pH 9 to 13. PMID:21516989

  10. Carbon dioxide capture using polyethylenimine-loaded mesoporous carbons.

    PubMed

    Wang, Jitong; Chen, Huichao; Zhou, Huanhuan; Liu, Xiaojun; Qiao, Wenming; Long, Donghui; Ling, Licheng

    2013-01-01

    A high efficiency sorbent for CO2 capture was developed by loading polyethylenimine (PEI) on mesoporous carbons which possessed well-developed mesoporous structures and large pore volume. The physicochemical properties of the sorbent were characterized by N2 adsorption/desorption, scanning electron microscopy (SEM), thermal gravimetric analysis (TG) and Fourier transform infrared spectroscopy (FT-IR) techniques followed by testing for CO2 capture. Factors that affected the sorption capacity of the sorbent were studied. The sorbent exhibited extraordinary capture capacity with CO2 concentration ranging from 5% to 80%. The optimal PEI loading was determined to be 65 wt.% with a CO2 sorption capacity of 4.82 mmol-CO2/g-sorbent in 15% CO2/N2 at 75 degrees C, owing to low mass-transfer resistance and a high utilization ratio of the amine compound (63%). Moisture had a promoting effect on the sorption separation of CO2. In addition, the developed sorbent could be regenerated easily at 100 degrees C, and it exhibited excellent regenerability and stability. These results indicate that this PEI-loaded mesoporous carbon sorbent should have a good potential for CO2 capture in the future. PMID:23586307

  11. Catalytic upgrading of xylan over mesoporous Y catalyst.

    PubMed

    Kim, Seong-Soo; Jun, Bo Ram; Park, Sung Hoon; Jeon, Jong-Ki; Suh, Dong Jin; Kim, Tae-Wan; Park, Young-Kwon

    2014-04-01

    In-situ catalytic cracking of xylan, a model compound of hemicellulose, was carried out using pyrolysis-gas chromatography/mass spectrometry over mesoporous Y for the first time. Experiments were conducted at three different temperatures, 400 degrees C, 450 degrees C, and 500 degrees C, to investigate the effect of reaction temperature. Three different biomass-to-catalyst ratios, 1:1, 1:2, and 1:3, were tested at 500 degrees C to examine the effect of catalyst dose. In addition, the catalytic activity of mesoporous Y was compared with that of Al-MCM-41. The catalysts used were characterized by N2 adsorption-desorption, temperature programmed desorption of NH3, and X-ray diffraction. The main pyrolysis products of xylan were acids, hydrocarbons, phenolics, oxygenates, aromatics, and polycyclic aromatic hydrocarbons. Mesoporous Y, which has acid sites with larger quantity and stronger acidity than those of Al-MCM-41, was shown to enhance the quality of bio-oil to a larger extent, producing a larger quantity of high-value-added products, such as aromatics and furans. PMID:24734712

  12. Study of carbon monoxide oxidation on mesoporous platinum.

    PubMed

    Esterle, Thomas F; Russell, Andrea E; Bartlett, Philip N

    2010-09-10

    H(1) mesoporous platinum surfaces formed by electrodeposition from lyotropic liquid crystalline templates have high electroactive surface areas (up to 60 m(2) g(-1)) provided by the concave surface within their narrow (≈2 nm diameter) pores. In this respect, they are fundamentally different from the flat surfaces of ordinary Pt electrodes or the convex surfaces of high-surface-area Pt nanoparticles. Cyclic voltammetry of H(1) mesoporous Pt films in acid solution is identical to that for polycrystalline Pt, suggesting that the surfaces of the pores are made up of low-index Pt faces. In contrast, CO stripping voltammetry on H(1) mesoporous Pt is significantly different from the corresponding voltammetry on polycrystalline Pt and shows a clear prewave for CO oxidation and the oxidation CO at lower overpotential. These differences in CO stripping are related to the presence of trough sites where the low-index Pt faces that make up the concave surface of the pore walls meet. PMID:20578119

  13. Evaluation of thermoporometry for characterization of mesoporous materials.

    PubMed

    Yamamoto, Takuji; Endo, Akira; Inagi, Yuki; Ohmori, Takao; Nakaiwa, Masaru

    2005-04-15

    The accuracy of thermoporometry (TPM) in terms of the characterization of SBA-15 is examined based on a model that classifies the water in the mesopores into two different types: freezable pore water, which can form cylindrical ice crystals, and nonfreezable pore water, which cannot undergo a phase transition during a differential scanning calorimetry (DSC) measurement. Applying the empirical relationship between the sizes of the ice crystals formed in the mesopores and the solidification temperature of the freezable pore water to a thermogram (a recording of the heat flux during the solidification of the freezable pore water) yielded a size distribution of the ice crystals. The size of the ice crystals increased slightly with repetitive freezing, indicating that the mesopores were enlarged by formation of the ice crystals. Adding the thickness, t(nf), of the nonfreezable pore water layer to the ice crystal-size distribution calculated from the thermogram allowed for the determination of the porous properties of SBA-15. The porous properties attained from TPM experiments were compared with the results attained through the combination of Ar gas adsorption experiments and nonlocal density functional theory (NLDFT) analysis. The porous properties determined by TPM were confirmed to be quite sensitive to the t(nf) value. PMID:15780301

  14. Aerosol-spray diverse mesoporous metal oxides from metal nitrates.

    PubMed

    Kuai, Long; Wang, Junxin; Ming, Tian; Fang, Caihong; Sun, Zhenhua; Geng, Baoyou; Wang, Jianfang

    2015-01-01

    Transition metal oxides are widely used in solar cells, batteries, transistors, memories, transparent conductive electrodes, photocatalysts, gas sensors, supercapacitors, and smart windows. In many of these applications, large surface areas and pore volumes can enhance molecular adsorption, facilitate ion transfer, and increase interfacial areas; the formation of complex oxides (mixed, doped, multimetallic oxides and oxide-based hybrids) can alter electronic band structures, modify/enhance charge carrier concentrations/separation, and introduce desired functionalities. A general synthetic approach to diverse mesoporous metal oxides is therefore very attractive. Here we describe a powerful aerosol-spray method for synthesizing various mesoporous metal oxides from low-cost nitrate salts. During spray, thermal heating of precursor droplets drives solvent evaporation and induces surfactant-directed formation of mesostructures, nitrate decomposition and oxide cross-linking. Thirteen types of monometallic oxides and four groups of complex ones are successfully produced, with mesoporous iron oxide microspheres demonstrated for photocatalytic oxygen evolution and gas sensing with superior performances. PMID:25897988

  15. Functionalized mesoporous silica nanoparticles for oral delivery of budesonide

    SciTech Connect

    Yoncheva, K.; Popova, M.; Szegedi, A.; Mihaly, J.; Tzankov, B.; Lambov, N.; Konstantinov, S.; Tzankova, V.; Pessina, F.; Valoti, M.

    2014-03-15

    Non-functionalized and amino-functionalized mesoporous silica nanoparticle were loaded with anti-inflammatory drug budesonide and additionally post-coated with bioadhesive polymer (carbopol). TEM images showed spherical shape of the nanoparticles and slightly higher polydispersity after coating with carbopol. Nitrogen physisorption and thermogravimetic analysis revealed that more efficient loading and incorporation into the pores of nanoparticles was achieved with the amino-functionalized silica carrier. Infrared spectra indicated that the post-coating of these nanoparticles with carbopol led to the formation of bond between amino groups of the functionalized carrier and carboxyl groups of carbopol. The combination of amino-functionalization of the carrier with the post-coating of the nanoparticles sustained budesonide release. Further, an in vitro model of inflammatory bowel disease showed that the cytoprotective effect of budesonide loaded in the post-coated silica nanoparticles on damaged HT-29 cells was more pronounced compared to the cytoprotection obtained with pure budesonide. -- Graphical abstract: Silica mesoporous MCM-41 particles were amino-functionalized, loaded with budesonide and post-coated with bioadhesive polymer (carbopol) in order to achieve prolonged residence of anti-inflammatory drug in GIT. Highlights: • Higher drug loading in amino-functionalized mesoporous silica. • Amino-functionalization and post-coating of the nanoparticles sustained drug release. • Achievement of higher cytoprotective effect with drug loaded into the nanoparticles.

  16. Adsorption behavior of natural anthocyanin dye on mesoporous silica

    NASA Astrophysics Data System (ADS)

    Kohno, Yoshiumi; Haga, Eriko; Yoda, Keiko; Shibata, Masashi; Fukuhara, Choji; Tomita, Yasumasa; Maeda, Yasuhisa; Kobayashi, Kenkichiro

    2014-01-01

    Because of its non-toxicity, naturally occurring anthocyanin is potentially suitable as a colorant for foods and cosmetics. To the wider use of the anthocyanin, the immobilization on the inorganic host for an easy handling as well as the improvement of the stability is required. This study is focused on the adsorption of significant amount of the natural anthocyanin dye onto mesoporous silica, and on the stability enhancement of the anthocyanin by the complexation. The anthocyanin has successfully been adsorbed on the HMS type mesoporous silica containing small amount of aluminum. The amount of the adsorbed anthocyanin has been increased by modifying the pore wall with n-propyl group to make the silica surface hydrophobic. The light fastness of the adsorbed anthocyanin has been improved by making the composite with the HMS samples containing aluminum, although the degree of the improvement is not so large. It has been proposed that incorporation of the anthocyanin molecule deep inside the mesopore is required for the further enhancement of the stability.

  17. Nucleation Pathways of CO2 Condensation under Mesoporous Templated Glass

    NASA Astrophysics Data System (ADS)

    Wang, Bo; Byran, Matthew S.; Warren, Garfield T.; Sokol, Paul E.; Indiana University Team; NIST Collaboration

    2015-03-01

    Carbon capture and storage (CCS) are important elements in reducing greenhouse gas emission and combating global warming. The adsorption behavior of CO2 under mesoporous confinement at room temperature is particularly relevant. , Small Angle Scattering of X-ray (SAXS) and Neutron (SANS) were used to probe the adsorption process of CO2 under such mesoporous confinement MCM-41 and details of nucleation pathways were mapped out by fitting the scattering intensities with adsorption models. From both experiments, the nucleation of CO2 on the inner pore surface of MCM-41 is found to be a two-step process; high density liquid phase CO2 first forms uniform layers following the long range translational symmetry of the porous matrix, above one CO2 filling, determined by the pore size and temperature, capillary condensation initiates. The nucleation sites formed during capillary condensation start to separate the long range symmetry from the one at uniform layers. Finally, SAXS and SANS techniques are compared and they both showed their unique properties of probing the filling-dependent structures of adsorbed CO2 under such mesoporous system.

  18. Hollow periodic mesoporous organosilica nanospheres by a facile emulsion approach.

    PubMed

    Ma, Xiaobo; Zhang, Junjie; Dang, Meng; Wang, Jin; Tu, Zenzen; Yuwen, Lihui; Chen, Guotao; Su, Xiaodan; Teng, Zhaogang

    2016-08-01

    Periodic mesoporous organosilicas (PMOs) with homogeneously incorporated organic groups, highly ordered mesopores, and controllable morphology have attracted increasing attention. In this work, one-step emulsion approach for preparation of hollow periodic mesoporous organosilica (HPMO) nanospheres has been established. The method is intrinsically simple and does not require any sacrificial templates, corrosive and toxic etching agents. The obtained HPMO nanospheres have high surface area (∼950m(2)g(-1)), accessible ordered mesochannels (∼3.4nm), large pore volume (∼3.96cm(3)g(-1)), high condensation degree (77%), and diameter (∼560nm), hollow chamber size (∼400nm), and shell thickness (∼80nm). Furthermore, cytotoxicity show the cell viability is higher than 86% after incubating with the HPMO nanospheres at a concentration of up to 1200μgmL(-1) for 24h. The hemolysis of HPMO nanospheres is lower than 1.1% at concentrations ranging from 10 to 2000μgmL(-1). The lower hemolysis and cytotoxicity make the HPMO nanospheres great promise for future biomedical applications. PMID:27156086

  19. Soft-Template-Synthesized Mesoporous Carbon for Oral Drug Delivery

    SciTech Connect

    Saha, Dipendu; Warren, Kaitlyn E; Naskar, Amit K

    2014-01-01

    Template-synthesized mesoporous carbons were successfully used in in vitro investigations of controlled delivery of three model drugs, captopril, furosemide, and ranitidine hydrochloride. Captopril and furosemide exhibited desorption kinetics over 30 40 h, and ranitidine HCl had a complete release time of 5 10 h. As evident from the slow release kinetics, we contend that our mesoporous carbon is an improved drug-delivery medium compared to state-of-the-art porous silica-based substrates. The mesoporous carbons, synthesized from phloroglucinol and lignin, a synthetic and a sustainable precursor, respectively, exhibit BET surface area of 200 400 m2 g-1 and pore volume of 0.2 0.6 cm3 g-1. The phloroglucinol-based carbon has narrower pore widths and higher pore volume than the lignin-derived counterpart and maintains a longer release time. Numerical modeling of the release kinetics data reveals that the diffusivities of all the drugs from lignin-based carbon media are of equivalent magnitude (10-22 to 10-24 m2 s-1). However, a tailored reduction of pore width in the sorbent reduces the diffusivity of smaller drug molecules (captopril) by an order of magnitude. Thus, engineered pore morphology in our synthesized carbon sorbent, along with its potential to tailor the chemistry of its interaction with sorbet, can be exploited for optimal delivery system of a preferred drug within its therapeutic level and below the level of toxicity.

  20. Processing and characterization of unidirectional thermoplastic nanocomposites

    NASA Astrophysics Data System (ADS)

    Narasimhan, Kameshwaran

    The manufacture of continuous fibre-reinforced thermoplastic nanocomposites is discussed for the case of E-Glass reinforced polypropylene (PP) matrix and for E-Glass reinforced Polyamide-6 (Nylon-6), with and without dispersed nanoclay (montmorillonite) platelets. The E-Glass/PP nanocomposite was manufactured using pultrusion, whereas the E-Glass/Nylon-6 nanocomposite was manufactured using compression molding. Mechanical characterization of nanocomposites were performed and compared with traditional microcomposites. Compressive as well as shear strength of nanocomposites was improved by improving the yield strength of the surrounding matrix through the dispersion of nanoclay. Significant improvements were achieved in compressive strength and shear strength with relatively low nanoclay loadings. Initially, polypropylene with and without nanoclay were melt intercalated using a single-screw extruder and the pultruded nanocomposite was fabricated using extruded pre-impregnated (pre-preg) tapes. Compression tests were performed as mandated by ASTM guidelines. SEM and TEM characterization revealed presence of nanoclay in an intercalated and partially exfoliated morphology. Mechanical tests confirmed significant improvements in compressive strength (˜122% at 10% nanoclay loading) and shear strength (˜60% at 3% nanoclay loading) in modified pultruded E-Glass/PP nanocomposites in comparison with baseline properties. Uniaxial tensile tests showed a small increase in tensile strength (˜3.4%) with 3% nanoclay loading. Subsequently, E-Glass/Nylon-6 nanocomposite panels were manufactured by compression molding. Compression tests were performed according to IITRI guidelines, whereas short beam shear and uni-axial tensile tests were performed according to ASTM standards. Mechanical tests confirmed strength enhancement with nanoclay addition, with a significant improvement in compressive strength (50% at 4% nanoclay loading) and shear strength (˜36% at 4% nanoclay loading

  1. Polylactide nanocomposites for packaging materials: A review

    NASA Astrophysics Data System (ADS)

    Widiastuti, Indah

    2016-02-01

    This review aims at highlighting on an attempt for improving the properties of polylactide (PLA) as packaging material by application of nanocomposite technology. PLA is attracting considerable interest because of more eco-friendliness from its origin as contrast to the petrochemical-based polymers and its biodegradability. Despite possessing good mechanical and optical properties, deterioration of the material properties in PLA materials during their service time could occur after prolonged exposure to humidity and high temperature condition. Limited gas barrier is another drawback of PLA material that should be overcome to satisfy the requirement for packaging application. To further extend the range of mechanical and thermal properties achievable, several attempts have been made in modifying the material such as blending with other polymers, use of plasticizing material and development of PLA nanocomposites. Nanocomposite is a fairly new type of composite that has emerged in which the reinforcing filler has nanometer scale dimensions (at least one dimension of the filler is less than 100 nm). In this review, the critical properties of PLA as packaging materials and its degradation mechanism are presented. This paper discusses the current effort and key research challenges in the development of nanocomposites based on biodegradable polymer matrices and nano-fillers. The PLA layered silicate nanocomposites where the filler platelets can be dispersed in the polymer at the nanometer scale owing to the specific filler surface modification, frequently exhibits remarkable improvements of mechanical strength, gas barrier and thermal stability.

  2. Semiconducting conjugated polymer-inorganic tetrapod nanocomposites.

    PubMed

    Jung, Jaehan; Pang, Xinchang; Feng, Chaowei; Lin, Zhiqun

    2013-06-25

    Cadmium telluride (CdTe) tetrapods were synthesized via multiple injections of the Te precursor by utilizing bifunctional ligands. Subsequently, tetrapod-shaped semiconducting inorganic-organic nanocomposites (i.e., P3HT-CdTe tetrapod nanocomposites) were produced by directly grafting conjugated polymer ethynyl-terminated poly(3-hexylthiophene) (i.e., P3HT-≡) onto azide-functionalized CdTe tetrapods (i.e., CdTe-N3) via a catalyst-free click chemistry. The intimate contact between P3HT and CdTe tetrapod rendered the effective dispersion of CdTe tetrapods in nanocomposites and facilitated their efficient electronic interaction. The success of coupling reaction was confirmed by Fourier transform infrared spectroscopy and nuclear magnetic resonance spectroscopy. The grafting density of P3HT chains on the CdTe tetrapods was estimated by thermogravimetric analysis. The photophysical properties of P3HT-CdTe tetrapod nanocomposites were studied using UV-vis and photoluminescence spectroscopies. These intimate semiconducting conjugated polymer-tetrapod nanocomposites may offer a maximized interface between conjugated polymers and tetrapods for efficient charge separation and enhanced charge transport regardless of their orientation for potential application in hybrid solar cells with improved power conversion efficiency. PMID:23600796

  3. Systematic comparison of model polymer nanocomposite mechanics.

    PubMed

    Xiao, Senbo; Peter, Christine; Kremer, Kurt

    2016-01-01

    Polymer nanocomposites render a range of outstanding materials from natural products such as silk, sea shells and bones, to synthesized nanoclay or carbon nanotube reinforced polymer systems. In contrast to the fast expanding interest in this type of material, the fundamental mechanisms of their mixing, phase behavior and reinforcement, especially for higher nanoparticle content as relevant for bio-inorganic composites, are still not fully understood. Although polymer nanocomposites exhibit diverse morphologies, qualitatively their mechanical properties are believed to be governed by a few parameters, namely their internal polymer network topology, nanoparticle volume fraction, particle surface properties and so on. Relating material mechanics to such elementary parameters is the purpose of this work. By taking a coarse-grained molecular modeling approach, we study an range of different polymer nanocomposites. We vary polymer nanoparticle connectivity, surface geometry and volume fraction to systematically study rheological/mechanical properties. Our models cover different materials, and reproduce key characteristics of real nanocomposites, such as phase separation, mechanical reinforcement. The results shed light on establishing elementary structure, property and function relationship of polymer nanocomposites. PMID:27623170

  4. Cellulose nanofibrils (CNF) filled boron nitride (BN) nanocomposites

    NASA Astrophysics Data System (ADS)

    Sulaiman, Hanisah Syed; Hua, Chia Chin; Zakaria, Sarani

    2015-09-01

    In this study, nanocomposite using cellulose nanofibrils filled with different percentage of boron nitride (CNF-BN) were prepared. The objective of this research is to study the effect of different percentage of BN to the thermal conductivity of the nanocomposite produced. The CNF-BN nanocomposite were characterization by FT-IR, SEM and thermal conductivity. The FT-IR analysis of the CNF-BN nanocomposite shows all the characteristic peaks of cellulose and BN present in all samples. The dispersion of BN in CNF were seen through SEM analysis. The effect of different loading percentage of BN to the thermal conductivity of the nanocomposite were also investigated.

  5. Cellulose nanofibrils (CNF) filled boron nitride (BN) nanocomposites

    SciTech Connect

    Sulaiman, Hanisah Syed; Hua, Chia Chin; Zakaria, Sarani

    2015-09-25

    In this study, nanocomposite using cellulose nanofibrils filled with different percentage of boron nitride (CNF-BN) were prepared. The objective of this research is to study the effect of different percentage of BN to the thermal conductivity of the nanocomposite produced. The CNF-BN nanocomposite were characterization by FT-IR, SEM and thermal conductivity. The FT-IR analysis of the CNF-BN nanocomposite shows all the characteristic peaks of cellulose and BN present in all samples. The dispersion of BN in CNF were seen through SEM analysis. The effect of different loading percentage of BN to the thermal conductivity of the nanocomposite were also investigated.

  6. Silica-based mesoporous nanobiomaterials as promoter of bone regeneration process.

    PubMed

    Shadjou, Nasrin; Hasanzadeh, Mohammad

    2015-11-01

    Silica-based mesostructured nanomaterials have emerged as a full family of biomaterials with tremendous potential to address the requirements for the bone regeneration process. This review focuses on more recent advances in bone regeneration process based on silica-based mesoporous biomaterials during 2012 to January 2015. In this review, we describe application of silica-based mesoporous mesostructured nanomaterials (possessing pore sizes in the range 2-50 nm) for the bone regeneration process. We summarize the preparation methods, the effect of mesopore templates and composition on the mesopore-structure characteristics, and different forms of these materials, including particles, fibers, spheres, scaffolds, and composites. The effect of structural and textural properties of mesoporous materials on the development of new biomaterials for treatment of different bone pathologies such as infection, osteoporosis, cancer, and so forth is discussed. In addition, silica-based mesoporous bioactive glass, as a potential drug/growth factor carrier, is reviewed, which includes the composition-structure-drug delivery relationship and the functional effect on the antibacteria and tissue-stimulation properties. Also, application of different mesoporous materials on construction of 3D macroporous scaffolds for bone tissue engineering was disused. Finally, this review discusses the possibility of covalently grafting different osteoinductive agents to the silica-based mesoporous scaffold surface that act as attracting signals for bone cells to promote the bone regeneration process. PMID:26011776

  7. A reconstruction strategy to synthesize mesoporous SAPO molecular sieve single crystals with high MTO catalytic activity.

    PubMed

    Wang, Chan; Yang, Miao; Li, Mingrun; Xu, Shutao; Yang, Yue; Tian, Peng; Liu, Zhongmin

    2016-05-11

    Mesoporous SAPO-34 single crystals with tunable porosity and Si content have been fast synthesized within 4 hours by a reconstruction strategy, which show excellent hydrothermal stability and MTO catalytic activity. This new strategy is further proven to be applicable to prepare other mesoporous SAPO molecular sieve single crystals. PMID:27101359

  8. Synthesis of organic-inorganic hybrid mesoporous tin oxophosphate in the presence of anionic surfactant.

    PubMed

    Mal, Nawal Kishor; Fujiwara, Masahiro; Matsukata, Masahiko

    2005-11-01

    Synthesis of novel mesoporous hybrid tin oxophosphate is reported from phenylphosphonic acid as the only precursor of phosphorus in the presence of anionic surfactant (SDS), which possesses a wormhole mesoporous structure and is stable even after calcination at 550 degrees C. PMID:16228034

  9. Surfactant-free synthesis of mesoporous and hollow silica nanoparticles with an inorganic template.

    PubMed

    Baù, Luca; Bártová, Barbora; Arduini, Maria; Mancin, Fabrizio

    2009-12-28

    A surfactant-free synthesis of mesoporous and hollow silica nanoparticles is reported in which boron acts as the templating agent. Using such a simple and mild procedure as a treatment with water, the boron-rich phase is selectively removed, affording mesoporous pure silica nanoparticles with wormhole-like pores or, depending on the synthetic conditions, silica nanoshells. PMID:20024287

  10. Studies on Supercapacitor Electrode Material from Activated Lignin-Derived Mesoporous Carbon

    SciTech Connect

    Saha, Dipendu; Li, Yunchao; Bi, Zhonghe; Chen, Jihua; Keum, Jong Kahk; Hensley, Dale K; Grappe, Hippolyte A.; Meyer III, Harry M; Dai, Sheng; Paranthaman, Mariappan Parans; Naskar, Amit K

    2014-01-01

    We synthesized mesoporous carbon from pre-cross-linked lignin gel impregnated with a surfactant as the pore-forming agent, and then activated the carbon through physical and chemical methods to obtain activated mesoporous carbon. The activated mesoporous carbons exhibited 1.5- to 6-fold increases in porosity with a maximum BET specific surface area of 1148 m2/g and a pore volume of 1.0 cm3/g. Slow physical activation helped retain dominant mesoporosity; however, aggressive chemical activation caused some loss of the mesopore volume fraction. Plots of cyclic voltammetric data with the capacitor electrode made from these carbons showed an almost rectangular curve depicting the behavior of ideal double-layer capacitance. Although the pristine mesoporous carbon exhibited the same range of surface-area-based capacitance as that of other known carbon-based supercapacitors, activation decreased the surface-area-based specific capacitance and increased the gravimetric-specific capacitance of the mesoporous carbons. Surface activation lowered bulk density and electrical conductivity. Warburg impedance as a vertical tail in the lower frequency domain of Nyquist plots supported good supercapacitor behavior for the activated mesoporous carbons. Our work demonstrated that biomass-derived mesoporous carbon materials continue to show potential for use in specific electrochemical applications.

  11. A bio-catalytically driven Janus mesoporous silica cluster motor with magnetic guidance.

    PubMed

    Ma, Xing; Sanchez, Samuel

    2015-03-28

    A bio-catalytic Janus motor based on the mesoporous silica cluster (JMSC) is fabricated. Chemically conjugated catalase triggers the decomposition of H2O2 to produce driving force by bubble propulsion, while a metallic (Ni) coating layer allows for magnetic guidance of the motor. The JMSC motor can act as a delivery vehicle with cargo loading inside its mesopores. PMID:25407318

  12. Ionic liquid decorated mesoporous silica nanoparticles: a new high-performance hybrid electrolyte for lithium batteries.

    PubMed

    Li, Yang; Wong, Ka-Wai; Ng, Ka-Ming

    2016-03-10

    We report a novel hybrid electrolyte based on mesoporous silica nanoparticles decorated with an ionic liquid, which exhibits a superior lithium ion transference number of >0.8, and an excellent electrochemical window of >5 V with attractive ionic conductivity. The insights obtained pave a new way for the preparation of high-performance electrolytes with mesoporous structures. PMID:26926805

  13. Hydrothermal synthesis of mesoporous metal oxide arrays with enhanced properties for electrochemical energy storage

    SciTech Connect

    Xiao, Anguo Zhou, Shibiao; Zuo, Chenggang; Zhuan, Yongbing; Ding, Xiang

    2015-01-15

    Highlights: • NiO mesoporous nanowall arrays are prepared via hydrothermal method. • Mesoporous nanowall arrays are favorable for fast ion/electron transfer. • NiO mesoporous nanowall arrays show good supercapacitor performance. - Abstract: Mesoporous nanowall NiO arrays are prepared by a facile hydrothermal synthesis method with a following annealing process. The NiO nanowall shows continuous mesopores ranging from 5 to 10 nm and grows vertically on the substrate forming a porous net-like structure with macropores of 20–300 nm. A plausible mechanism is proposed for the growth of mesoporous nanowall NiO arrays. As cathode material of pseudocapacitors, the as-prepared mesoporous nanowall NiO arrays show good pseudocapacitive performances with a high capacitance of 600 F g{sup −1} at 2 A g{sup −1} and impressive high-rate capability with a specific capacitance of 338 F g{sup −1} at 40 A g{sup −1}. In addition, the mesoporous nanowall NiO arrays possess good cycling stability. After 6000 cycles at 2 A g{sup −1}, a high capacitance of 660 F g{sup −1} is attained, and no obvious degradation is observed. The good electrochemical performance is attributed to its highly porous morphology, which provides large reaction surface and short ion diffusion paths, leading to enhanced electrochemical properties.

  14. A facile route to synthesize endurable mesopore containing ZSM-5 catalyst for methanol to propylene reaction.

    PubMed

    Sun, Chao; Du, Junming; Liu, Jian; Yang, Yisu; Ren, Nan; Shen, Wei; Xu, Hualong; Tang, Yi

    2010-04-21

    A novel route is proposed for the preparation of mesopore containing zeolite ZSM-5 via in situ hydrothermal treatment of a solution containing alkali-dissolved SBA-15 containing carbonized surfactant P123 in the mesopores; it exhibited prominent stability enhancement for methanol to propylene reaction. PMID:20461876

  15. Ultrasound assisted morphological control of mesoporous silica with improved lysozyme adsorption.

    PubMed

    Sun, Shumin; Wang, Shen; Wang, Peiyuan; Wu, Qiong; Fang, Shaoming

    2015-03-01

    The morphological control of mesoporous silica without any additives has attracted much attention. Discrete rod-like and string-of-beads like mesoporous SBA-15 can be achieved under ultrasound irradiation without changing the composition of synthesis system. The smaller particles of SBA-15 showed improved lysozyme immobilization capacity and higher adsorption rate over conventional rope-like SBA-15. PMID:25150609

  16. Facile preparation of mesoporous carbon-silica-coated graphene for the selective enrichment of endogenous peptides.

    PubMed

    Zhang, Quanqing; Zhang, Qinghe; Xiong, Zhichao; Wan, Hao; Chen, Xiaoting; Li, Hongmei; Zou, Hanfa

    2016-01-01

    A sandwich-like composite composed of ordered mesoporous carbon-silica shell-coated graphene (denoted as graphene@mSiO2-C) was prepared by an in-situ carbonation strategy. A mesoporous silica shell was synthesized by a sol-gel method, and cetyltrimethyl ammonium bromide inside the mesopores were in-situ carbonized as a carbon source to obtain a carbon-silica shell. The resulting mesoporous carbon-silica material with a sandwich structure possesses a high surface area (600 m(2) g(-1)), large pore volume (0.587 cm(3) g(-1)), highly ordered mesoporous pore (3 nm), and high carbon content (30%). This material shows not only high hydrophobicity of graphene and mesoporous carbon but also a hydrophilic silica framework that ensures excellent dispersibility in aqueous solution. The material can capture many more peptides from bovine serum albumin tryptic digests than mesoporous silica shell-coated graphene, demonstrating great enrichment efficiency for peptides. Furthermore, the prepared composite was applied to the enrichment of low-abundance endogenous peptides in human serum. Based on Matrix-Assisted Laser Desorption/ Ionization Time of Flight Mass Spectrometry identification, the graphene@mSiO2-C could efficiently size-exclude proteins and enriches the low-abundant peptides on the graphene and mesoporous carbon. And based on the LC-MS/MS results, 892 endogenous peptides were obtained by graphene@mSiO2-C, hinting at its great potential in peptides analysis. PMID:26695263

  17. Mesoporous hexagonal Co3O4 for high performance lithium ion batteries

    PubMed Central

    Su, Dawei; Xie, Xiuqiang; Munroe, Paul; Dou, Shixue; Wang, Guoxiu

    2014-01-01

    Mesoporous Co3O4 nanoplates were successfully prepared by the conversion of hexagonal β-Co(OH)2 nanoplates. TEM, HRTEM and N2 sorption analysis confirmed the facet crystal structure and inner mesoporous architecture. When applied as anode materials for lithium storage in lithium ion batteries, mesoporous Co3O4 nanocrystals delivered a high specific capacity. At 10 C current rate, as-prepared mesoporous Co3O4 nanoplates delivered a specific capacity of 1203 mAh/g at first cycle and after 200 cycles it can still maintain a satisfied value (330 mAh/g). From ex-situ TEM, SAED and FESEM observation, it was found that mesoporous Co3O4 nanoplates were reduced to Li2O and Co during the discharge process and re-oxidised without losing the mesoporous structure during charge process. Even after 100 cycles, mesoporous Co3O4 crystals still preserved their pristine hexagonal shape and mesoporous nanostructure. PMID:25283174

  18. Effect of Nickel Contents on the Microstructure of Mesoporous Nickel Gadolinium-Doped Ceria

    NASA Astrophysics Data System (ADS)

    Ahn, Seunghyun; Koo, Hyun; Bae, Sung-Hwan; Park, Chan; Cho, Guyoung; Chang, Ikwhang; Cha, Suk-Won; Yoo, Young-Sung

    2013-12-01

    The effect of NiO contents on the microstructure of mesoporous NiO-Gd0.25Ce0.75O2-x (NiO-GDC) composite for intermediate temperature solid oxide fuel cells (IT-SOFC) was investigated. Mesoporous NiO-GDC powders with different NiO contents were synthesized by self-assembly hydrothermal method using tri-block copolymer, Pluronic F127, as a structure directing agent. Grain growth/agglomeration behaviors of NiO particles and changes of mesoporous structure of GDC particles were characterized by microstructural analyses. NiO-GDC powders were composed of GDC nano particles with ordered mesopore inside the particles and octahedral NiO grains with truncated-edges. As the amount of NiO increases, specific area value of mesoporous NiO-GDC was decreased, and the agglomeration/growth behavior of NiO grains was accelerated.

  19. Mesoporous hybrids containing Eu 3+ complexes covalently bonded to SBA-15 functionalized: Assembly, characterization and photoluminescence

    NASA Astrophysics Data System (ADS)

    Li Kong, Li; Yan, Bing; Li, Ying

    2009-07-01

    A novel series of luminescent mesoporous organic-inorganic hybrid materials has been prepared by linking Eu 3+ complexes to the functionalized ordered mesoporous SBA-15 which was synthesis by a co-condensation process of 1,3-diphenyl-1,3-propanepione (DBM) modified by the coupling agent 3-(triethoxysilyl)-propyl isocyanate (TEPIC), tetraethoxysilane (TEOS), Pluronic P123 surfactant as a template. It was demonstrated that the efficient intramolecular energy transfer in the mesoporous material Eu(DBMSi-SBA-15) 3phen mainly occurred between the modified DBM (named as DBM-Si) and the central Eu 3+ ion. So the Eu(DBMSi-SBA-15) 3phen showed characteristic emission of Eu 3+ ion under UV irradiation with higher luminescence quantum efficiency. Moreover, the mesoporous hybrid materials exhibited excellent thermal stability as the lanthanide complex was covalently bonded to the mesoporous matrix.

  20. Mesoporous metal oxide microsphere electrode compositions and their methods of making

    DOEpatents

    Parans Paranthaman, Mariappan; Bi, Zhonghe; Bridges, Craig A; Brown, Gilbert M

    2014-12-16

    Compositions and methods of making are provided for treated mesoporous metal oxide microspheres electrodes. The compositions comprise (a) microspheres with an average diameter between 200 nanometers (nm) and 10 micrometers (.mu.m); (b) mesopores on the surface and interior of the microspheres, wherein the mesopores have an average diameter between 1 nm and 50 nm and the microspheres have a surface area between 50 m.sup.2/g and 500 m.sup.2/g, and wherein the composition has an electrical conductivity of at least 1.times.10.sup.-7 S/cm at 25.degree. C. and 60 MPa. The methods of making comprise forming a mesoporous metal oxide microsphere composition and treating the mesoporous metal oxide microspheres by at least one method selected from the group consisting of: (i) annealing in a reducing atmosphere, (ii) doping with an aliovalent element, and (iii) coating with a coating composition.