scholarly journals Silver Nanoparticles on Cellulose Surfaces: Quantitative Measurements

Nanomaterials ◽  
2019 ◽  
Vol 9 (5) ◽  
pp. 780 ◽  
Author(s):  
Ana Patrícia Carapeto ◽  
Ana Maria Ferraria ◽  
Ana Maria Botelho do Rego

In this work, cellulose films pre-activated with carbonyldiimidazole (CDI) and grafted with 1,6-hexanediamine, were decorated with silver nanoparticles (AgNPs). The generation of AgNPs was followed by quartz crystal microbalance (QCM). The obtained films were characterized by X-Ray Photoelectron Spectroscopy (XPS) and imaged by atomic force microscopy (AFM). XPS confirmed the synthesis in situ of AgNPs on the film attesting their oxidation state. The results from the three techniques were compared showing how sound the quantitative treatment of the results issued from these techniques can be. The main objective of this work is exactly to show that the quantitative exploration of the results of different characterization techniques can and should be practiced systematically instead of just comparing them qualitatively.

2005 ◽  
Vol 20 (5) ◽  
pp. 1139-1145 ◽  
Author(s):  
Jeremiah T. Abiade ◽  
Wonseop Choi ◽  
Rajiv K. Singh

To understand the ceria–silica chemical mechanical polishing (CMP) mechanisms, we studied the effect of ceria slurry pH on silica removal and surface morphology. Also, in situ friction force measurements were conducted. After polishing; atomic force microscopy, x-ray photoelectron spectroscopy, and scanning electron microscopy were used to quantify the extent of the particle–substrate interaction during CMP. Our results indicate the silica removal by ceria slurries is strongly pH dependent, with the maximum occurring near the isoelectric point of the ceria slurry.


2002 ◽  
Vol 17 (7) ◽  
pp. 1622-1633 ◽  
Author(s):  
Xiaowu Fan ◽  
Mi-Kyoung Park ◽  
Chuanjun Xia ◽  
Rigoberto Advincula

Nanostructured montmorillonite/poly(diallyldimethylammonium chloride) multilayer thin films were fabricated up to 100 layers thick by stepwise alternating polyelectrolyte and clay deposition from solution. The structure and morphology of the films were characterized by x-ray diffraction, ellipsometry, atomic force microscopy, and quartz crystal microbalance ex situ and in situ measurements. The mechanical properties were tested by nanoindentation. The hardness of the multilayer thin film was 0.46 GPa. The thin film's modulus was correlated to its ordering and anisotropic structure. Both hardness and modulus of this composite film were higher than those of several other types of polymer thin films.


2006 ◽  
Vol 6 (3) ◽  
pp. 748-755 ◽  
Author(s):  
M. Sendova ◽  
M. Sendova-Vassileva ◽  
J. C. Pivin ◽  
H. Hofmeister ◽  
K. Coffey ◽  
...  

Thin films of silica containing silver nanoparticles were deposited by magnetron co-sputtering followed by thermal annealing in air or Ar + 2% H2. Laser fragmentation of the particles was carried out at two different wavelengths. The films were characterized by UV-VIS absorption spectroscopy and plasmon resonance numerical modeling based on the Mie theory, together with Rutherford backscattering elemental analysis, X-ray photoelectron spectroscopy chemical characterization, combined with statistical analysis of the transmission electron microscopy micrographs, and surface topography study by atomic force microscopy. It is demonstrated that the fragmentation is a result of a thermal process and its mechanism does not depend on the laser wavelength as long as the laser light is absorbed by the silver particles. Laser treatment with moderate fluences does not alter the precipitated metal content while fragmenting the particles. TEM study indicates that laser assisted silver particle modification can serve as a method for narrowing the particle size distribution.


Molecules ◽  
2020 ◽  
Vol 25 (18) ◽  
pp. 4041
Author(s):  
Diego Mauricio Sánchez-Osorno ◽  
Diego Gomez-Maldonado ◽  
Cristina Castro ◽  
María Soledad Peresin

The interactions between films of bacterial nanocellulose (BNC) and B complex vitamins were studied using a Quartz Crystal Microbalance with Dissipation monitoring (QCM-D). Thin films of BNC were generated in situ by QCM-D, followed by real-time measurements of the vitamin adsorption. The desorption of vitamins was induced by rinsing the system using phosphate buffers at a pH of 2 and 6.5, emulating gastric conditions. Changes in frequency (which are proportional to changes in adsorbed mass, ∆m) detected by QCM-D were used to determine the amounts of vitamin adsorbed and released from the BNC film. Additionally, changes in dissipation (∆D) were proven to be useful in identifying the effects of the pH in both pristine cellulose films and films with vitamin pre-adsorbed, following its changes during release. The effects of pH on the morphology of the vitamin-BNC surfaces were also monitored by changes in rugosity from images obtained by atomic force microscopy (AFM). Based on this data, we propose a model for the binding phenomena, with the contraction on the relaxation of the cellulose film depending on pH, resulting in an efficient vitamin delivery process.


2011 ◽  
Vol 393-395 ◽  
pp. 1313-1317
Author(s):  
Da Pan Li ◽  
Ying Zi Wang ◽  
Yan Li Chen

A perylenetetracarboxylic diimide derivative, N,N,N′,N′-tetra(hydroxyethyl)-1,7-di (4-tert-butylphenol)perylene-3,4:9,10-tetracarboxylic diimide(THPDI), was synthesized and covalently self-assembled as a monolayer on the modified a quartz surface. UV-vis absorption and IR spectra revealed the H-aggregate nature of THPDI molecules in the obtained thin solid film. With this thin solid film as a template, CdS nanoparticles were deposited on it in situ, which were characterized by electronic absorption, X-ray photoelectron spectroscopy (XPS) and atomic force microscopy (AFM). The morphology of CdS nanoparticles is disklike, and the diameter is ca. 150 nm as determined by AFM. The present result provides an effective and new method toward directed growth of specific morphologies of the nanoparticles. It is believed helpful for designing and preparing molecular-based nano-electronic and nano-optoelectronic devices with good performance.


Author(s):  
Замир Валериевич Шомахов ◽  
Светлана Сергеевна Налимова ◽  
Рустам Мухамедович Калмыков ◽  
Кирилл Аубекеров ◽  
Вячеслав Алексеевич Мошников

Слои диоксида олова синтезированы гидротермальным методом из водного раствора SnF. Наночастицы серебра осаждены на поверхность полученных слоев методом фотовосстановления. Проведено исследование морфологии поверхности образцов методом атомно-силовой микроскопии. Размер наночастиц серебра зависит от концентрации раствора AgNO, используемого для проведения реакции фотовосстановления. При синтезе из раствора с концентрацией 0,02 М размер полученных наночастиц составляет варьируется от 10 до 100 нм, при увеличении концентрации раствора в два раза размер наночастиц составляет порядка 100 нм. С помощью рентгеновской фотоэлектронной спектроскопии изучен состав поверхности слоев до и после осаждения наночастиц серебра. При выбранных условиях синтеза формируется слой диоксида олова без посторонних включений, и происходит осаждение металлического серебра. Химический сдвиг пиков олова и кислорода после осаждения наночастиц серебра свидетельствует об обмене электронами между оловом и серебром. Полученные слои представляют интерес для применения в области полупроводниковых адсорбционных газовых сенсоров. Tin dioxide layers were synthesized by hydrothermal method from an aqueous solution of SnF. Silver nanoparticles were deposited on the surface of the obtained layers by the photoreduction method. The surface morphology of the samples was studied by atomic force microscopy. The size of the silver nanoparticles depends on the concentration of the AgNO solution used for the photoreduction reaction. When synthesized from 0,02 M solution with a concentration of, the size of the nanoparticles varies from 10 to 100 nm, when the concentration of the solution is doubled, the size of the nanoparticles is about 100 nm. The surface composition of the layers before and after the deposition of silver nanoparticles was studied using the X-ray photoelectron spectroscopy. It was shown that a layer of the tin dioxide is formed without external inclusions, and metallic silver is deposited. The chemical shift of the peaks of tin and oxygen after the deposition of silver nanoparticles indicates the exchange of electrons between tin and silver. The synthesized layers are of interest for application in the field of semiconductor adsorption gas sensors.


Les/Wood ◽  
2021 ◽  
Vol 70 (1) ◽  
Author(s):  
Sebastian Dahle ◽  
Lienhard Wegewitz ◽  
Wolfgang Viöl ◽  
Wolfgang Maus-Friedrichs

Metastable Induced Electron Spectroscopy, Ultraviolet Photoelectron Spectroscopy (He I and He II), X-ray Photoelectron Spectroscopy, and Atomic Force Microscopy were employed to study the interaction of silver with lignin as well as with two of its natural precursors, coniferyl alcohol and sinapyl alcohol. For all three of them, no chemical interaction between the adsorbed silver and the organic substrate was found before contact with air. Nevertheless, silver nanoparticles were found in all three cases after contact with air. Thus, a process of silver nanoparticle formation during the decomposition of the organic molecules is suggested, similar to the previously found catalytic decomposition of cinnamyl alcohol by water in the presence of silver atoms.


2003 ◽  
Vol 780 ◽  
Author(s):  
C. Essary ◽  
V. Craciun ◽  
J. M. Howard ◽  
R. K. Singh

AbstractHf metal thin films were deposited on Si substrates using a pulsed laser deposition technique in vacuum and in ammonia ambients. The films were then oxidized at 400 °C in 300 Torr of O2. Half the samples were oxidized in the presence of ultraviolet (UV) radiation from a Hg lamp array. X-ray photoelectron spectroscopy, atomic force microscopy, and grazing angle X-ray diffraction were used to compare the crystallinity, roughness, and composition of the films. It has been found that UV radiation causes roughening of the films and also promotes crystallization at lower temperatures.Furthermore, increased silicon oxidation at the interface was noted with the UVirradiated samples and was shown to be in the form of a mixed layer using angle-resolved X-ray photoelectron spectroscopy. Incorporation of nitrogen into the film reduces the oxidation of the silicon interface.


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