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chemistry. nanocomposite

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...
August 14, 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...
July 25, 2018: 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...
July 30, 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...
July 16, 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
Antonin Desmecht, Timothy Steenhaut, Florence Pennetreau, Sophie Hermans, Olivier Riant
Polyamidoamine (PAMAM) dendrimers were covalently immobilized on multi-walled carbon nanotubes (MWNT) by two "grafting to" strategies. We demonstrate the existence of non-covalent interactions between the two components but outline the superiority of our two grafting approaches, namely xanthate and click chemistry. MWNT surfaces were functionalized with activated ester and propargylic moieties prior to their reaction with PAMAM or azido-PAMAM dendrimers, respectively. The grafting of PAMAM generations 0 to 3 was evaluated with X-ray photoelectron spectroscopy (XPS), thermogravimetric analysis (TGA), and transmission electron microscopy (TEM)...
June 20, 2018: Chemistry: a European Journal
Coit T Hendley, Lee A Fielding, Elizabeth R Jones, Anthony J Ryan, Steven P Armes, Lara A Estroff
Recently, it has become clear that a range of nanoparticles can be occluded within single crystals to form nanocomposites. Calcite is a much-studied model, but even in this case we have yet to fully understand the details of the nanoscale interactions at the organic-inorganic interface that lead to occlusion. Here, a series of diblock copolymer nanoparticles with well-defined surface chemistries were visualized interacting with a growing calcite surface using in situ atomic force microscopy. These nanoparticles comprise a poly(benzyl methacrylate) (PBzMA) core-forming block and a non-ionic poly(glycerol monomethacrylate) (Ph-PGMA), a carboxylic acid-tipped poly(glycerol monomethacrylate) (HOOC-PGMA), or an anionic poly(methacrylic acid) (PMAA) stabilizer block...
June 27, 2018: Journal of the American Chemical Society
Teodora Gancheva, Nick Virgilio
This work demonstrates that a model system of poly( N-isopropylacrylamide) (PNIPAam) macroporous hydrogels, with tailored microstructures and comprising gold (Au) or silver (Ag) nanoparticles, display enhanced and tunable catalytic activity. These nanocomposites are prepared using polymer templates obtained from melt-processed cocontinuous polymer blends. The reaction rate, controlled by both hydrogel porosity and the PNIPAam lower critical solution temperature, increases by more than an order of magnitude as compared to nonporous gels, and is comparable to micro- or nanocarrier-based systems, with easier catalyst recovery...
June 27, 2018: ACS Applied Materials & Interfaces
Cheyann Lee Wetteland, Huinan Liu
This article reports a new process for creating polymer-based nanocomposites with enhanced dispersion of ceramic nanoparticles without using any surfactants, and the resulted changes in their optical and biological properties. Specifically, dispersion of two different ceramic nanoparticles, i.e, hydroxyapatite (nHA) and magnesium oxide (nMgO) nanoparticles, in a model biodegradable polymer, namely poly (lactic-co-glycolic acid) (PLGA), was studied. High-power sonication was integrated with dual asymmetric centrifugal (DAC) mixing to improve dispersion of nanoparticles during solvent casting...
June 14, 2018: Journal of Biomedical Materials Research. Part A
Hugo H C de Lima, Vicente L Kupfer, Murilo P Moisés, Marcos R Guilherme, Jaqueline de C Rinaldi, Sérgio L Felisbino, Adley F Rubira, Andrelson W Rinaldi
This work reports the preparation, the characterization and the prednisolone release profile of biocompatible hydrogel nanocomposites containing mesoporous silica (SBA) and alginate as a biomaterial for enhanced drug delivery with reduced burst effect and improved mechanical properties. Such systems, which were prepared using specific SBA/alginate-crosslinking chemistry, exhibited interconnecting pore hybrid network owing to both mesoporous silica and hydrogel characteristics. Activated SBA was shown to be a determinant factor in inhibiting initial burst by nearly 90% and the drug was released with minimal burst kinetics...
September 15, 2018: Carbohydrate Polymers
Xuyang Zheng, Shiping Xu, Yao Wang, Xiang Sun, Yuan Gao, Baoyu Gao
In order to achieve remarkable synergy between adsorption and photocatalysis for antibiotics elimination from water, in this study, a graphitized mesoporous carbon (GMC)-TiO2 nanocomposite was successfully synthesized by an extended resorcinol-formaldehyde (R-F) method. In the composite, the lamellar GMC nanosheets possessed large specific surface area and mesoporous structure, and could adsorb and enrich antibiotics effectively. This could not only reduce the antibiotic concentration in water shortly, but also greatly increase the chances for antibiotics to contact with and be degraded by photocatalysts and active species...
October 1, 2018: Journal of Colloid and Interface Science
Dwaipayan Ghosh, Benny Febriansyah, Disha Gupta, Leonard Kia-Sheun Ng, Shibo Xi, Yonghua Du, Tom Baikie, ZhiLi Dong, Han Sen Soo
Catalyst deactivation is a persistent problem not only for the scientific community but also in industry. Isolated single-site heterogeneous catalysts have shown great promise to overcome these problems. Here, a versatile anchoring strategy for molecular complex immobilization on a broad range of semiconducting or insulating metal oxide ( e. g., titanium dioxide, mesoporous silica, cerium oxide, and tungsten oxide) nanoparticles to synthesize isolated single-site catalysts has been studied systematically. An oxidatively stable anchoring group, maleimide, is shown to form covalent linkages with surface hydroxyl functionalities of metal oxide nanoparticles by photoclick chemistry...
May 22, 2018: ACS Nano
Zhen-Yu Wu, Hai-Wei Liang, Bi-Cheng Hu, Shu-Hong Yu
Carbon aerogels that are typically prepared using sol-gel chemistry have unique three dimensional networks of interconnected nanometer-sized particles and thus exhibit many fascinating physical properties and great application potentials in widespread fields. To boost the practical applications, it is urgent to develop efficient and low-cost methods to produce high-performance carbon aerogels in large-scale, preferably in a sustainable way. In 2012, two new classes of aerogels consisting of carbon nanofiber (CNF) networks were prepared from biomass-derived precursor by chemosynthesis (i...
May 16, 2018: Angewandte Chemie
Zhen Liu, Jingquan Liu, Yichao Wang, Joselito M Razal, Paul S Francis, Mark J Biggs, Colin J Barrow, Wenrong Yang
Dispersing graphene oxide (GO) in low-polar solvents can realize a perfect self-assembly with functional molecules and application in removal of organic impurities that only dissolve in low-polar solvents. The surface chemistry of GO plays an important role in its dispersity in these solvents. The direct transfer of hydrophilic GO into low-polar solvents, however, has remained an experimental challenge. In this study, we design an interface to transfer GO by simultaneously 'pushing and pulling' the nanosheets into low-polar solvents...
August 3, 2018: Nanotechnology
Milena Nadgorny, Amir Ameli
Three-dimensional printing (3DP) has attracted a considerable amount of attention during the past years, being globally recognized as one of the most promising and revolutionary manufacturing technologies. Although the field is rapidly evolving with significant technological advancements, materials research remains a spotlight of interest, essential for the future developments of 3DP. Smart polymers and nanocomposites, which respond to external stimuli by changing their properties and structure, represent an important group of materials that hold a great promise for the fabrication of sensors, actuators, robots, electronics, and medical devices...
May 30, 2018: ACS Applied Materials & Interfaces
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