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1.
Kyung Ju Lee Jung Tae Park Joo Hwan Goh Jong Hak Kim 《Journal of polymer science. Part A, Polymer chemistry》2008,46(12):3911-3918
A microphase‐separated, amphiphilic graft copolymer consisting of a poly (vinyl chloride) (PVC) backbone and poly(oxyethylene methacrylate) (POEM) side chains, (PVC‐g‐POEM at 62:38 wt %) was synthesized via atom transfer radical polymerization (ATRP). Nuclear magnetic resonance (1H NMR), FTIR spectroscopy, and transmission electron microscopy (TEM) clearly revealed that the “grafting from” method using ATRP was successful and that the graft copolymer molecularly self‐assembled into discrete nanophase domains of continuous PVC and isolated POEM regions. The self‐assembled graft copolymer film was used to template the growth of silver nanoparticles in solid state by introducing a AgCF3SO3 precursor and a UV irradiation process. The in situ formation of silver nanoparticles in the graft copolymer template film was confirmed by TEM, UV–visible spectroscopy, and wide angle X‐ray scattering. FTIR spectroscopy and X‐ray photoelectron spectroscopy also demonstrated the selective incorporation and in situ formation of silver nanoparticles within the hydrophilic POEM domains, presumably due to strong interactions between the silver and the ether oxygen in POEM. © 2008 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 46: 3911–3918, 2008 相似文献
2.
Mesoporous carbons containing silver nanoparticles have been successfully synthesized under acidic conditions by employing
resorcinol and formaldehyde as carbon precursors and triblock copolymer EO101PO56EO101 (Lutrol F127) as a soft template. Silver nanoparticles of ∼90 nm were added to the synthesis mixture to achieve 10 wt% and
20 wt% of Ag loading in the carbon. Also, tetraethyl orthosilicate (TEOS) was introduced to the system in order to improve
adsorption properties of the silver-carbon composites and to reinforce its structure. The resulting carbons with incorporated
silver nanoparticles featured high surface areas, large total pore volumes and primary mesopores in the range between ∼6–7 nm. 相似文献
3.
Joo Hwan Koh Yong Woo Kim Jung Tae Park Jong Hak Kim 《Journal of Polymer Science.Polymer Physics》2008,46(7):702-709
In this study, poly(vinylidene fluoride‐co‐chlorotrifluoroethylene)‐graft‐poly(oxyethylene methacrylate), P(VDF‐co‐CTFE)‐g‐POEM, an amphiphilic comb copolymer with hydrophobic P(VDF‐co‐CTFE) backbone and hydrophilic POEM side chains at 73:27 wt % was synthesized. The POEM side chains were grafted from the P(VDF‐co‐CTFE) mainchain backbone via atom transfer radical polymerization (ATRP) using direct initiation of the chlorine atoms in CTFE units. Synthesis of microphase‐separated P(VDF‐co‐CTFE)‐g‐POEM comb copolymer was successful, as confirmed by nuclear magnetic resonance (1H NMR), FTIR spectroscopy, and transmission electron microscopy (TEM). Nanocomposite films were prepared using the comb copolymer as a template film and the in situ reduction of AgCF3SO3 precursor to silver nanoparticles under UV irradiation. Silver nanoparticles with 4–8 nm in average size were in situ created in the solid state template film, as revealed by TEM, UV–visible spectroscopy, and wide angle X‐ray scattering (WAXS). Differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA) presented the selective incorporation and the in situ growth of silver nanoparticles within the hydrophilic POEM domains of microphase‐separated comb copolymer film. © 2008 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 46: 702–709, 2008 相似文献
4.
Yong Woo Kim Do Kyoung Lee Kyung Ju Lee Byoung Ryul Min Jong Hak Kim 《Journal of Polymer Science.Polymer Physics》2007,45(11):1283-1290
Silver nanoparticles were prepared by UV irradiation from silver salts, such as AgBF4 or AgNO3, when dissolved in an amphiphilic film of poly((oxyethylene)9 methacrylate)‐graft‐poly((dimethyl siloxane)n methacrylate), POEM‐g‐mPDMS. The in situ formation of silver nanoparticles in the graft copolymer film was confirmed by transmission electron microscopy (TEM), UV‐visible spectroscopy, and wide angle X‐ray scattering (WAXS). The results demonstrated that the use of AgBF4 yielded silver nanoparticles with a smaller size (~5 nm) and narrower particle distribution when compared with AgNO3. The formation of silver nanoparticles was explained in terms of the interaction strength of the silver ions with the ether oxygens of POEM, as revealed by differential scanning calorimetry (DSC) and X‐ray photoelectron spectroscopy (XPS). It was thus concluded that a stronger interaction of silver ions with the ether oxygens results in a more stable formation of silver nanoparticles, which produces uniform and small‐sized nanoparticles. DSC and small angle X‐ray scattering (SAXS) data also showed the selective incorporation and in situ reduction of the silver ions within the hydrophilic POEM domains. Excellent mechanical properties of the nanocomposite films (3–5 × 105 dyn/cm2) were observed, mostly because of the confinement of silver nanoparticles in the POEM chains as well as interfaces created by the microphase separation of the graft copolymer film. © 2007 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 45: 1283–1290, 2007 相似文献
5.
L. Bois F. Chassagneux F. Bessueille N. Destouches N. Moncoffre N. Toulhoat 《Journal of solid state chemistry》2009,182(7):1700-25208
Elaboration of mesostructured silica films with a triblock copolymer polyethylene oxide-polypropylene oxide-polyethylene oxide, (PEO-PPO-PEO) and controlled growth of silver nanoparticles in the mesostructure are described. The films are characterized using UV-visible optical absorption spectroscopy, TEM, AFM, SEM, X-ray diffraction (XRD) and Rutherford backscattering spectrometry (RBS). Organized arrays of spherical silver nanoparticles with diameter between 5 and 8 nm have been obtained by NaBH4 reduction. The size and the repartition of silver nanoparticles are controlled by the film mesostructure. The localization of silver nanoparticles exclusively in the upper-side part of the silica-block copolymer film is evidenced by RBS experiment. On the other hand, by using a thermal method, 40 nm long silver sticks can be obtained, by diffusion and coalescence of spherical particles in the silica-block copolymer layer. In this case, migration of silver particles toward the glass substrate-film interface is shown by the RBS experiment. 相似文献
6.
A. M. Eremenko N. P. Smirnoval I. P. Mukhal H. R. Yashan 《Theoretical and Experimental Chemistry》2010,46(2):65-88
Methods of synthesis, optical characteristics, morphology, and catalytic and bactericidal characteristics of composite materials
based on silica (films and powders) containing nanoparticles of silver, gold, and their binary compounds with alloy or core–shell
structure are examined. The photochemical reduction of Au3+ and Ag+ with a photocatalyst (a film of SiO2 with adsorbed benzophenone) makes it possible to generate stable nanoparticles of gold and silver in solutions for subsequent
introduction into adsorbents and catalysts. Examples of the use of nanosized composites in catalysis and in microbiological
experiments are presented. 相似文献
7.
Herein we present extensive studies that were undertaken to develop a new copolymer with distinctive characteristics for utilization in different applications particularly in conductive textiles. The copolymer is based on graft polymerization of cellulose nanowhiskers (CNWs) with acrylamide and therefore nominated CNW-polyacrylamide (PAAm) copolymer. Development of this copolymer comprises preparation of CNWs from purified cotton sliver as per the acid hydrolysis method, followed by copolymerization of the freshly prepared CNWs with AAm at different feeding ratios for the sake of product optimization in the presence of K2S2O8 as initiator. Thus, obtained CNW-PAAm copolymers were characterized by making use of the proper instruments and analysis facilities. Following this, the newly prepared and promising copolymer was selected and used as a precursor in the green synthesis of silver and copper nanoparticles. The crystal nature of CNWs as cellulose I remains unaltered after copolymerization, but the crystallinity decreases. According to thermal gravimetric analysis, the copolymer is much more thermally stable than CNWs. The CNW-PAAm copolymer can be used successfully as a highly functional, effective and adequate precursor for green synthesis of silver and copper nanoparticles as shown by UV-Vis spectral analysis and transmission electron microscopy micrographs. A multi-branched shape and hyperbranched shape-like tree involving silver nanoparticles and the PAAm graft of the copolymer are formed. Furthermore, Cu nanoparticles are chosen as a candidate for conductive fabrics application. 相似文献
8.
The sixth-generation hydroxyl-ended hyperbranched poly(amine-ester) (G6-OH) was investigated as template in formation and stabilization of copper nanoparticles. Ultra-violet spectra and transmission electron microscope were adopted to characterize absorption properties of G6-OH(Cu2+)n complex and the morphology of the formed particles (G6-OH(Cu)n), respectively. The template and stabilization functions of G6-OH were compared with di-block copolymer micelles and dendrimers having similar structure. It was found that the hyperbranched polymers could act as the templates for the preparation of copper particles. The size of the formed copper particles increased with Cu2+/Gn-OH molar ratio. Besides, the oxygen influenced the chemistry stability of copper particles greatly. 相似文献
9.
Although the diameter of conductive polymer nanoparticles can be controlled effectively, the uniformity of particle length is still very challenging. In this study, with the temperature‐sensitive block copolymer PS111‐b‐PNIPAM114 as the template, the morphology and size of polyaniline (PANI) particles had been controllably adjusted through the change of temperature. Additionally, the electrochemical performance of each sample was investigated. After PS111‐b‐PNIPAM114 was synthesized through the reversible addition‐fragmentation chain transfer radical polymerization (RAFT), with its vesicular micelle as the “template”, the PANI particles with uniform length distribution were prepared successfully at 40°C. The average length of PANI particles after template removal was 254.07 nm with a short tail distribution, which was closer to the average than the standard normal distribution. Electrochemical results of PANI showed that it had good electrochemical activity with fast charge and discharge ability. And, with the current density of 1 A·g?1, its discharge‐specific capacitance could reach up to 805.61 F·g?1. 相似文献
10.
Room temperature synthesis of silver nanoparticles has been successfully achieved by adding NaOH acting as an accelerator
for the reduction of silver ions in ethylene glycol and glycerol without adding any external reducing agent. Highly monodisperse
silver particles are obtained in the presence of various stabilisers such as PVP, SiO2 and SDS. Nanoparticles with a mean diameter of 25 nm and a mean deviation of 2 nm could be obtained under experimental conditions.
The silver nanoparticles so obtained could be easily transferred to chloroform containing CTAB, giving rise to CTAB stabilised
silver nanoparticles having sizes of around 25 nm. The newly found role of OH− stabilisation was used to formulate a mechanism for the formation of silver nanoparticles in ethylene glycol and glycerol.
In this mechanism, silver nanoparticles are stabilised in ethylene glycol by the adsorbed OH− ions. 相似文献
11.
G. V. Krylova Yu. I. Gnatyuk N. P. Smirnova A. M. Eremenko V. M. Gun’ko 《Journal of Sol-Gel Science and Technology》2009,50(2):216-228
A variety of Ag nanoparticles/oxide mesoporous films with templated silica, titania, and zirconia was synthesized by sol–gel
method at glass, aluminum, and silicon substrates using metal alkoxides (tetraethoxysilane, titanium tetraisopropoxide, and
zirconium tetrapropoxide) and AgNO3 as precursors of oxide films and Ag nanoparticles, respectively, and Pluronic P123 as a template agent. Oxide films alone
and Ag/oxide composites were characterized using hexane adsorption, X-ray diffraction (XRD), Raman and ultraviolet (UV)/vis
spectroscopies, scanning electron microscopy (SEM) and transmission electron microscopy (TEM) methods. The distribution of
Ag nanoparticles within the films, their sizes, intensity, and position of surface plasmon resonance (SPR) absorbance band
at λ = 400 nm, as well as the textural and structural characteristics of whole films depend on treatment temperature, types of
substrates and oxide matrices, oxide crystallization, and Ag content. Ag nanoparticles form preferably on the outer surface
of the films under lower sintering temperatures if the amount of loaded silver is low. Oxide crystallization (e.g., TiO2) promotes silver embedding into the outer film layer. At higher silver content (≥10 at.%) and higher calcination temperature
(873 K), silver nanoparticles could be entrapped more uniformly along the film profile because of more intensive evaporation
of silver droplets from the outer surface of the films on heating. 相似文献
12.
Interactions between colloidal copper and silver ions lead to the formation of silver nanoparticles. The reaction proceeds through the intermediate stage of the formation of a copper-silver contact pair. The formation of bimetallic AgcoreCushell nanoparticles is observed in the presence of the “seeding” silver nanoparticles and upon the simultaneous radiochemical reduction of Ag+ and Cu2+ ions. 相似文献
13.
M. Ider K. Abderrafi A. Eddahbi S. Ouaskit A. Kassiba 《Journal of Cluster Science》2017,28(3):1051-1069
Silver nanoparticles were synthesized by the reduction of the silver nitrate (AgNO3) using the latex copolymer in ethanol solution under microwave (MW) heating. The reaction parameters such as silver precursor concentration (from 0.005 to 0.1 g/l) and MW power (200–800 W) significantly affect the formation rate, shape, size and distribution of the silver nanoparticles. A significant reduction of irradiation time was observed when the MW energy is compared to conventional thermal reduction processes. The prepared silver nanoparticles show uniform and stable sizes from 5 to 11 nm, which can be stored at room temperature for approximately 12 months without any visible change. These peculiarities indicate that the latex copolymer is a good stabilizer for the silver nanoparticles. The optical properties, morphology, and crystalline structure of the silver-latex copolymer nanocomposites were characterized by the Ultraviolet–Visible spectroscopy, transmission electron microscopy (TEM) and scanning electron microscopy (SEM). The study of the TEM images at high magnifications identified the silver nanoparticles as face-centered cubic (fcc) structure with spherical and hexagonal shapes. 相似文献
14.
《Radiation Physics and Chemistry》2007,76(5):811-817
Reduction of silver ion in a silver–phytic acid (1:1 ratio) system has been studied using pulse radiolysis technique. Time-resolved transformation of the intermediates, Ag+→Ag0→Ag2+→Ag32+, has been clearly observed in the reduction of silver–phytic acid (1:1) system. The effect of phytic acid on the formation and decay of initial silver clusters has been also studied. The surface plasmon absorption band of stable silver nanoparticle (410 nm) and dynamic light scattering technique has been used to characterize the nanoparticles and measure the average size (Rav=100 nm). 相似文献
15.
Silver oxalate Ag2C2O4, was already proposed for soldering applications, due to the formation when it is decomposed by a heat treatment, of highly sinterable silver nanoparticles. When slowly decomposed at low temperature (125 °C), the oxalate leads however to silver nanoparticles isolated from each other. As soon as these nanoparticles are formed, the magnetic susceptibility at room temperature increases from −3.14 10−7 emu.Oe−1.g−1 (silver oxalate) up to −1.92 10−7 emu.Oe−1.g−1 (metallic silver). At the end of the oxalate decomposition, the conventional diamagnetic behaviour of bulk silver, is observed from room temperature to 80 K. A diamagnetic-paramagnetic transition is however revealed below 80 K leading at 2 K, to silver nanoparticles with a positive magnetic susceptibility. This original behaviour, compared to the one of bulk silver, can be ascribed to the nanometric size of the metallic particles. 相似文献
16.
A new nanostructure photocatalyst, incorporating Ag and reduced graphene oxide (rGO) with LaMnO3-nanorods have been fabricated via two-step synthetic approaches by using Cetyltrimethyl Ammonium Bromide (CTAB) as a template via a simple hydrothermal reaction and the decoration of Ag nanoparticles is through a traditional silver mirror reaction. The characteristic of the materials are examined by XRD, TEM, FE-SEM and XPS. The results confirm that the LaMnO3 nanorods are perovskite phase and uniform dispersed on the surface of rGO. The Ag nanoparticles is deposited the surface of LaMnO3-nanorods with its metal form. The Ag/LaMnO3-nanorods/rGO exhibit an excellent performance in the photo-degradation of Direct Green BE under the UV-vis irradiation. As an electron capture agent, metal Ag can capture the e− that transported along the LMO-NR, thereby leading to effective separation of the e−-h+ pairs and accelerate the transfer of surface charge, which is further demonstrated by the Photoluminescence (PL) spectra, cyclic voltammetry (CV) and AC impedance spectra. 相似文献
17.
A method has been developed for studying the presence of micellar aggregates in block and graft copolymers. Specimens for examination in the electron microscope were prepared using a freeze-etching/replication technique. Four well-characterized copolymers were studied: a polystyrene-polyisoprene two-block copolymer, a (polystyrene-polyisoprene-)4Si star-block copolymer, and two polystyrene-g-polyisoprene graft copolymers. Technical white oil, which is a very poor solvent for polystyrene, was taken as the solvent for the copolymers. For the purpose of comparison, a study was also made of specimens prepared from polystyrene homopolymer dissolved in a 1:1 mixture by vol of technical white oil and toluene. 相似文献
18.
A. N. Eryomin A. V. Pietkievich A. V. Abakshonok Yu. V. Siniutsich Zh. V. Ignatovich V. E. Agabekov M. K. Al-Muhanna 《Russian Journal of General Chemistry》2016,86(8):1886-1895
Co-precipitation and ultrasonic treatment methods have been used for the in situ formation of the composites of hydroxyapatite (HA) covered with nanoparticles of magnetite as well as compositions of magnetite, gold and silver. The thioalkyl-substituted derivatives of 2-arylaminopyrimidine, structural analogs of antitumor drug Imatinib containing one or two SH groups and capable to chemisorption on hydroxyapatite and its nanocomposites, have been synthesized. Two-component Fe3O4(HA) and three-component Fe3O4(HA)Au and Fe3O4(HA)Ag composites have been found the most promising as nanocarriers of bioactive compounds. 相似文献
19.
Liu Zhaolin Tay Siok Wei Hong Liang Lee Jim Yang 《Journal of Solid State Electrochemistry》2011,15(1):205-209
Olivine-type LiFePO4 composite materials for cathode material of the lithium-ion batteries were synthesized by using a sol-gel method and were
coated by a chemical deposition of silver particles. As-obtained LiFePO4/C-Ag (2.1 wt.%) composites were characterized by transmission electron microscopy (TEM), powder X-ray diffraction (XRD),
conductivity measurements, cyclic voltammetry, as well as galvanostatic measurements. The results revealed that the discharge
capacity of the LiFePO4/C-Ag electrode is 136.6 mAh/g, which is 7.6% higher than that of uncoated LiFePO4/C electrode (126.9 mAh/g). The LiFePO4/C coated by silver nanoparticles enhances the electrode conductivity and specific capacity at high discharge rates. The improved
capacity at high discharge rates may be attributed to increased electrode conductivity and the synergistic effect on electron
and Li+ transport after silver incorporation. 相似文献
20.
Muhammad Iqbal Michael McCullough Adam Harris S. Holger Eichhorn 《Journal of Thermal Analysis and Calorimetry》2012,108(3):933-938
Polyurethane composites containing spherical and flake-shaped silver fillers of micrometer and nanometer sizes were prepared by reacting suspensions of the silver filler in tetraethylene glycol with Desmodur? HL BA. Both the thermal conductivity and the stability of the silver composites are increased in comparison with a reference polyurethane sample without filler. Unexpectedly, the largest increases in thermal conductivity and stability are observed for the spherical silver particles of micrometer size but not for the silver nanoparticles, which is reasoned with larger aggregates of silver particles and a higher degree of crystallinity in the sample containing micrometer-sized silver particles. 相似文献