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chemistry. nanocomposite

Xiaoqing Cui, Hong Zhao, Zengxi Li
Abnormal concentration of hydrogen peroxide (H2 O2 ) in blood plasma and cells may lead to several diseases. Thus, it is important to develop a selective and sensitive method to monitor H2 O2 . In the present work, a novel nonenzymatic H2 O2 -sensing platform based on cobalt oxyhydroxide (CoOOH)/reduced graphene oxide (RGO) nanocomposite was fabricated. CoOOH nanoflakes were firstly synthesized via soft chemistry routes and then assembled on the surface of RGO. A series of characterizations by X-ray diffraction, X-ray photoelectron spectroscopy, and transmission electron microscopy demonstrated that hexagonal CoOOH nanoflakes were well distributed on the surface of RGO...
October 11, 2018: Analytical and Bioanalytical Chemistry
Sandra S Gkermpoura, Konstantinia D Papadimitriou, Emmanuel N Skountzos, Ioannis Polyzos, Maria Giovanna Pastore Carbone, Athanasios Kotrotsos, Vlasis G Mavrantzas, Costas Galiotis, Constantinos Tsitsilianis
3-Arm PMMAs end-functionalized by pyrene were designed as dispersing/stabilizing agents for the liquid-phase exfoliation of graphite in low-boiling point solvents like chloroform. The synthetic procedure comprised ARGET ATRP controlled polymerization, click chemistry and the quaternization reaction of triazole, ensuring tailor-made, well-defined pyrene-functional star PMMAs. Among a series of different pyrene-functional macromolecular topologies, the (PMMA-py2)3 proved the most efficient exfoliation agent giving relatively high graphene concentration (0...
October 9, 2018: Nanoscale
Kizkitza González, Clara García-Astrain, Arantzazu Santamaria-Echart, Lorena Ugarte, Luc Avérous, Arantxa Eceiza, Nagore Gabilondo
Starch-based hydrogels were performed by Diels-Alder cross-linking reactions between furan-modified starch and a water soluble bismaleimide, with improving conducting properties by using graphene layers as active nanofillers. The characterization results demonstrated that the Diels-Alder reaction and the corresponding conditions for the hydrogel formation were appropriate. The effect of increasing the furan/maleimide ratio on the architecture of the hydrogels and on the morphological, rheological and swelling properties were thoroughly evaluated...
December 15, 2018: Carbohydrate Polymers
S Rößler, C Heinemann, B Kruppke, A S Wagner, S Wenisch, H P Wiesmann, T Hanke
The intent of the present study was to demonstrate that multiphasic silica/collagen xerogels are able to manipulate cellular processes. These xerogels were prepared by a sol-gel approach allowing the incorporation of mineral phases. The resulting nanocomposites are designed as biomaterial for bone regeneration. Human osteoclasts derived from peripheral blood mononuclear cells were cultured both indirectly and directly, either in presence of different xerogel types or on their surface, to investigate the factor with the main influence on osteoclastogenesis...
December 1, 2018: Materials Science & Engineering. C, Materials for Biological Applications
Jegan Athinarayanan, Vaiyapuri Subbarayan Periasamy, Rajapandiyan Krishnamoorthy, Ali A Alshatwi
Graphene nanocomposites have received attention for the therapy and detection of diseases. In this study, we developed a simple and green chemistry approach for synthesizing Cu2 O/graphene nanocomposites (Cu2 O/G) using date palm fruit syrup as a reducing agent. The graphene oxide surface anchored with Cu(OH)2 and reduced it to fabricate Cu2 O-anchored graphene nanosheets using date palm fruit syrup. Physicochemical characteristics of the synthesized nanocomposites were analyzed. Scanning electron microscopy images revealed 50-70 nm Cu2 O nanostructures anchored on the surface of crumpled graphene sheets...
December 1, 2018: Materials Science & Engineering. C, Materials for Biological Applications
Allison Jansto, Eric M Davis
While the introduction of nanoparticles into Nafion membranes has proven to be a viable method to tune the ion selectivity in energy storage technologies such as the vanadium redox flow battery, there still remains a limited understanding of the fundamental mechanism by which the nanoparticles selectively restrict ion crossover. Herein, the surface chemistry and loading of SiO2 nanoparticles (SiNPs) were systematically varied to elucidate the relationship between nanoparticle dispersion (or dispersion state) and vanadium ion permeability in Nafion nanocomposite membranes...
October 9, 2018: ACS Applied Materials & Interfaces
Asieh Soozanipour, Asghar Taheri-Kafrani
Enzymes are used as biocatalysts for analytical purposes in diagnostics and preparative purposes in large-scale industrial processes. Despite perfect catalytic properties of enzymes, their industrial applications are limited due to the drawbacks regarding the lack of long-term stability under process conditions. The difficulties associated with recycling have to be resolved before enzyme implementation at industrial scale. Enzyme immobilization, as a novel approach, can improve the half-life, stability, catalytic activity, and reusability of enzymes...
2018: Methods in Enzymology
Ashwaq A Al-Hashedi, Marco Laurenti, Mohamed Amine Mezour, Tayebeh Basiri, Heithem Touazine, Mohamed Jahazi, Faleh Tamimi
Oral hygiene and regular maintenance are crucial for preserving good peri-implant health. However, available prophylaxis products and toothpastes, which are optimized for cleaning teeth, tend to contaminate and abrade implant surfaces due to their organic components and silica microparticles, respectively. This study aims to develop an organic-free implant-paste based on two-dimensional nanocrystalline magnesium phosphate gel and hydrated silica nanoparticles (20-30% w/w) for cleaning oral biofilm on titanium dental implants...
September 8, 2018: Journal of Biomedical Materials Research. Part B, Applied Biomaterials
Khouloud Jlassi, A Bahgat Radwan, Kishor Kumar Sadasivuni, Miroslav Mrlik, Aboubakr M Abdullah, Mohamed M Chehimi, Igor Krupa
Epoxy polymer nanocomposites filled with magnetite (Fe3 O4 ) clay (B), named (B-DPA-PANI@Fe3 O4 ) have been prepared at different filler loading (0.1, 0.5, 1, 3, 5 wt. %). The surface modification of clay by polyaniline (PANI) is achieved in the presence of 4-diphenylamine diazonium salt (DPA). The effects of the nanofiller loading on Tensile, mechanical and dielectric properties were systematically studied. Improved properties was highlighted for all reinforced samples. The addition of only 3 wt. % of the filler enhanced the tensile strength of the composites by 256%, and the glass transition temperature Tg by 37%...
September 6, 2018: Scientific Reports
Jibo Dou, Qiang Huang, Hongye Huang, Defu Gan, Junyu Chen, Fengjie Deng, Yuanqing Wen, Xiaoli Zhu, Xiaoyong Zhang, Yen Wei
A novel ternary composite consisting of Mg/Al layered double hydroxides (LDH), polydopamine (PDA) and poly(methyl vinyl ether-alt-maleic anhydride) (PMVE-MA) was fabricated by a facile combination of mussel-inspired chemistry and a ring-opening reaction. Dopamine can serve as a "minimalist mimic" of mussel adhesive protein to form a layer of polydopamine (PDA) on the LDH surface under rather mild conditions (including air atmosphere, aqueous solution, and catalyst free). Subsequently, the PMVE-MA brushes were immobilized onto the PDA modified LDH via a ring-opening reaction...
January 1, 2019: Journal of Colloid and Interface Science
Usman Ali Khan, Jianjun Liu, Jinbo Pan, Shengli Zuo, Hecheng Ma, Yingchun Yu, Aftab Ahmad, Sadeeq Ullah, Baoshan Li
In this paper, we present the fabrication of an expanded-perlite (EP)-based floating photocatalyst comprising CdS and Ag nanoparticles. In the Ag-CdS/EP nanocomposite, Ag-CdS was introduced as the photocatalytically active components and EP was employed as a low cost and sustainable support to reduce the problem of easy aggregation and improve the floating behavior of the designed catalyst. The Ag-CdS/EP photocatalyst was characterized via transmission electron microscopy (TEM), high-resolution transmission electron microscopy (HR-TEM), scanning electron microscopy (SEM), X-ray diffraction (XRD), UV-vis diffuse spectroscopy (UV-vis DRS), energy dispersive spectroscopy (EDS), X-ray photoelectron spectroscopy (XPS), and photoluminescence (PL) and photoelectrochemical measurements...
September 11, 2018: Dalton Transactions: An International Journal of Inorganic Chemistry
Thanh Binh Nguyen, C P Huang, Ruey-An Doong
A ZnFe2 O4 -TiO2 nanocomposite combining p-type ZnFe2 O4 and n-type TiO2 was successfully fabricated. The ZnFe2 O4 -TiO2 nanocomposite greatly enhanced the bisphenol A (BPA) photodegradation under visible light irradiation at 465 ± 40 nm. Loading TiO2 with 1 wt% of ZnFe2 O4 produced high photocurrent and low charge transfer resistance. The photodegradation rate of BPA by ZnFe2 O4 -TiO2 , which was highly dependent on the water chemistry including pH, anions, and humic acid, was 20.8-21.4 times higher than that of commercial TiO2 photocatalysts...
January 1, 2019: Science of the Total Environment
Rüstem Keçili, Chaudhery Mustansar Hussain
Molecularly imprinted polymers (MIPs) are a type of tailor-made materials that have ability to selectively recognize the target compound/s. MIPs have gained significant research interest in solid-phase extraction, catalysis, and sensor applications due to their unique properties such as low cost, robustness, and high selectivity. In addition, MIPs can be prepared as composite nanomaterials using nanoparticles, multiwalled carbon nanotubes (MWCNTs), nanorods, quantum dots (QDs), graphene, and clays. This review paper aims to demonstrate and highlight the recent progress of the applications of imprinted nanocomposite materials in analytical chemistry...
2018: International Journal of Analytical Chemistry
Massimo Tawfilas, Michele Mauri, Luca De Trizio, Roberto Lorenzi, Roberto Simonutti
Nanocrystals (NCs) surface characterization is a fundamental step for understanding the physical and chemical phenomena involved at the nanoscale. Surface energy and chemistry depend on particle size and composition, and, in turn, determine the interaction of NCs with the surrounding environment, their properties and stability, and the feasibility of nanocomposites. This work aims at extracting more information on the surface of different titanium dioxide polymorphs using 1 H-TD-NMR of water. Taking advantage of the interaction between water molecules and titanium dioxide NCs, it is possible to correlate the proton transverse relaxation times ( T2 ) as the function of the concentration and the specific surface area (δp · Cm ) and use it as an indicator of the crystal phase...
August 14, 2018: Langmuir: the ACS Journal of Surfaces and Colloids
Emilio Scalise, Vishwas Srivastava, Eric Janke, Dmitri Talapin, Giulia Galli, Stefan Wippermann
Semiconducting nanomaterials synthesized using wet chemical techniques play an important role in emerging optoelectronic and photonic technologies. Controlling the surface chemistry of the nano building blocks and their interfaces with ligands is one of the outstanding challenges for the rational design of these systems. We present an integrated theoretical and experimental approach to characterize, at the atomistic level, buried interfaces in solids of InAs nanoparticles capped with Sn2 S6 4- ligands. These prototypical nanocomposites are known for their promising transport properties and unusual negative photoconductivity...
September 2018: Nature Nanotechnology
Christoph O Blattmann, Sotiris E Pratsinis
Polymer nanocomposites are employed in (micro)electronic, biomedical, structural and optical applications. Their fabrication is challenging due to nanoparticle (filler) agglomeration and settling, increased viscosity of blended solutions and multiple tedious processing steps, just to name a few. Often this leads to an upper limit for filler content, requirements for filler⁻polymer interfacial chemistry and expensive manufacturing. As a result, novel but simple processes for nanocomposite manufacture that overcome such hurdles are needed...
July 10, 2018: Materials
Dongxiao Wen, Qianrui Liu, Ying Cui, Huaixia Yang, Jinming Kong
A novel nanocomposite of nanoporous gold nanoparticles (np-AuNPs) functionalized with 2,2,6,6-tetramethyl-1-piperidinyloxy radical (TEMPO) was prepared; assembled carboxyl groups on gold nanoporous nanoparticles surface were combined with TEMPO by the "bridge" of carboxylate-zirconium-carboxylate chemistry. SEM images and UV-Vis spectroscopies of np-AuNPs indicated that a safe, sustainable, and simplified one-step dealloying synthesis approach is successful. The TEMPO-np-AuNPs exhibited a good performance for the electrochemical detection of H2 O2 due to its higher number of electrochemical activity sites and surface area of 7...
2018: International Journal of Analytical Chemistry
Juan Zufía-Rivas, Puerto Morales, Sabino Veintemillas-Verdaguer
Aqueous dispersions of magnetic nanocomposites have been proposed as draw electrolytes in forward osmosis. One possible approach for the production of nanocomposites based on magnetite nanoparticles and sodium polyacrylate is the synthesis of the magnetic iron oxide by coprecipitation or oxidative precipitation in the presence of an excess of the polymer. In this work, we explored the effect of the polymer proportion on the nanomaterials produced by these procedures. The materials obtained were compared with those obtained by the coating of magnetite nanocrystals produced beforehand with the same polymer...
June 27, 2018: Nanomaterials
Denis Mihaela Panaitescu, Sorin Vizireanu, Cristian Andi Nicolae, Adriana Nicoleta Frone, Angela Casarica, Lavinia Gabriela Carpen, Gheorghe Dinescu
Tailoring the surface properties of nanocellulose to improve the compatibility of components in polymer nanocomposites is of great interest. In this work, dispersions of nanocellulose in water and acetonitrile were functionalized by submerged plasmas, with the aim of increasing the quality of this reinforcing agent in biopolymer composite materials. Both the morphology and surface chemistry of nanocellulose were influenced by the application of a plasma torch and filamentary jet plasma in a liquid suspension of nanocellulose...
June 26, 2018: Nanomaterials
Dipak Dutta, Andita Nataria Fitri Ganda, Jui-Kung Chih, Cheng-Chun Huang, Chung-Jen Tseng, Ching-Yuan Su
Graphene is impermeable to all molecules and has high chemical stability, which makes it an excellent anticorrosion coating for metals. However, current studies have indicated that galvanic coupling between graphene and a metal actually accelerates corrosion at the interface. Due to the insulating nature of polymers, graphene-polymer composite coatings with a strong interaction between the filler and the polymer matrix are an alternative means of addressing this issue. Nevertheless, such coatings require well-dispersed graphene flakes to lengthen the diffusion paths of gases or liquids, while preventing the formation of a conducting network from graphene to the metal...
July 9, 2018: Nanoscale
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