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Nanomaterials
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New Developments in Nanomaterial Analysis
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New Developments in Nanomaterial Analysis

A special issue of Nanomaterials (ISSN 2079-4991).

Deadline for manuscript submissions: closed (30 April 2012) | Viewed by 94800

Special Issue Editor

Prof. Dr. Shirley Chiang

E-Mail Website
Guest Editor
Department of Physics, University of California Davis, One Shields Avenue, Davis, CA 95616-5270, USA
Interests: nanotechnology; nanomaterials; surface microscopy; surface physics and chemistry; scanning probe microscopy (STM, AFM, ultrahigh vacuum); low energy electron microscopy (LEEM); X-ray photoemission spectroscopy (XPS); metals on semiconductors; graphene, adsorption on surfaces; surface phase transitions
Special Issues, Collections and Topics in MDPI journals

Special Issue Information

Dear Colleagues,

A special issue of Nanomaterials will discuss “New Developments in Nanomaterial Analysis.” Both the development of new instrumentation and the application of established characterization techniques to the nanometer realm are of interest, as they advance the studies of nanomaterials. Topics can include characterization, analysis, modeling, and modification studies on various types of nanomaterials, including organic, inorganic, hybrid, and biological ones. We invite submissions of original research articles or comprehensive reviews on, but not limited to, the following topics:

  • Novel characterization techniques applied to nanomaterials
  • Scanning probe microscopy, including scanning tunneling microscopy, atomic force microscopy, and near-field optical microscopy, of nanomaterials
  • Electron microscopy, including transmission electron microscopy, scanning electron microscopy, and low energy electron microscopy, of nanomaterials
  • Optical studies, including fluorescence and single-molecule techniques, of nanomaterials
  • X-ray microscopy and spectroscopy of nanomaterials
  • Nanoparticles used as imaging probes
  • Modeling nanomaterials
  • Manipulating and modifying nanomaterials

Prof. Dr. Shirley Chiang
Guest Editor

Keywords

  • scanned probe microscopy
  • scanning tunneling microscopy
  • atomic force microscopy
  • near field optical microscopy
  • transmission electron microscopy
  • scanning electron microscopy
  • low energy electron microscopy
  • x-ray microscopy
  • optical spectroscopy using fluorescence and single-molecule techniques
  • nanostructured materials (including organic, inorganic, hybrid, and biological ones)
  • nanoclusters
  • nanoparticles
  • nanotubes
  • graphene
  • quantum dots
  • thin films and coatings

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2489 KiB  
Article
Spectroscopic Characterization of Copper-Chitosan Nanoantimicrobials Prepared by Laser Ablation Synthesis in Aqueous Solutions
by Maria Chiara Sportelli, Annalisa Volpe, Rosaria Anna Picca, Adriana Trapani, Claudio Palazzo, Antonio Ancona, Pietro Mario Lugarà, Giuseppe Trapani and Nicola Cioffi
Nanomaterials 2017, 7(1), 6; https://doi.org/10.3390/nano7010006 - 30 Dec 2016
Cited by 25 | Viewed by 6363
Abstract
Copper-chitosan (Cu-CS) nanoantimicrobials are a novel class of bioactive agents, providing enhanced and synergistic efficiency in the prevention of biocontamination in several application fields, from food packaging to biomedical. Femtosecond laser pulses were here exploited to disrupt a Cu solid target immersed into [...] Read more.
Copper-chitosan (Cu-CS) nanoantimicrobials are a novel class of bioactive agents, providing enhanced and synergistic efficiency in the prevention of biocontamination in several application fields, from food packaging to biomedical. Femtosecond laser pulses were here exploited to disrupt a Cu solid target immersed into aqueous acidic solutions containing different CS concentrations. After preparation, Cu-CS colloids were obtained by tuning both Cu/CS molar ratios and laser operating conditions. As prepared Cu-CS colloids were characterized by Fourier transform infrared spectroscopy (FTIR), to study copper complexation with the biopolymer. X-ray photoelectron spectroscopy (XPS) was used to elucidate the nanomaterials’ surface chemical composition and chemical speciation of the most representative elements. Transmission electron microscopy was used to characterize nanocolloids morphology. For all samples, ξ-potential measurements showed highly positive potentials, which could be correlated with the XPS information. The spectroscopic and morphological characterization herein presented outlines the characteristics of a technologically-relevant nanomaterial and provides evidence about the optimal synthesis parameters to produce almost monodisperse and properly-capped Cu nanophases, which combine in the same core-shell structure two renowned antibacterial agents. Full article
(This article belongs to the Special Issue New Developments in Nanomaterial Analysis)
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Figure 1

Figure 1
<p>Transmission electron microscopy (TEM) images of laser-generated Cu nanoparticles (CuNPs) in the presence of different chitosan (CS) concentrations and corresponding size distribution histograms. Sizing could not be performed on 3 g/L CuNPs-CS nanocomposite, because of the massive presence of organic matrix.</p> Full article ">Figure 2
<p>C1s high-resolution regions of freshly-prepared CuNPs-CS nanocomposites synthetized at a CS concentration of: (<b>a</b>) no CS; (<b>b</b>) 0.01 g/L; (<b>c</b>) 0.1 g/L; (<b>d</b>) 1 g/L; (<b>e</b>) 3 g/L; (<b>f</b>) pure CS.</p> Full article ">Figure 3
<p>N1s high-resolution regions of freshly-prepared CuNPs-CS nanocomposites synthetized at CS concentration of: (<b>a</b>) 0.01 g/L; (<b>b</b>) 0.1 g/L; (<b>c</b>) 1 g/L; (<b>d</b>) 3 g/L; (<b>e</b>) pure CS.</p> Full article ">Figure 4
<p>Cu2p<sub>3/2</sub> high-resolution regions of freshly-prepared CuNPs-CS nanocomposites synthetized at CS concentrations of: (<b>a</b>) no CS; (<b>b</b>) 0.01 g/L; (<b>c</b>) 0.1 g/L; (<b>d</b>) 1 g/L; (<b>e</b>) 3 g/L.</p> Full article ">Figure 5
<p>Fourier transform infrared (FTIR) spectra of freshly-prepared CuNPs stabilized by CS (CuNPs@CS nanocomposites, “@” stands for “stabilized by”), synthetized at CS concentrations of: (<b>a</b>) 0.01 g/L; (<b>b</b>) 0.1 g/L; (<b>c</b>) 1 g/L; (<b>d</b>) 3 g/L.</p> Full article ">
424 KiB  
Article
A Strategy for Hydroxide Exclusion in Nanocrystalline Solid-State Metathesis Products
by Jiaqi Cheng and Kristin M. Poduska
Nanomaterials 2013, 3(3), 317-324; https://doi.org/10.3390/nano3030317 - 24 Jun 2013
Cited by 20 | Viewed by 8109
Abstract
We demonstrate a simple strategy to either prevent or enhance hydroxide incorporation in nanocrystalline solid-state metathesis reaction products prepared in ambient environments. As an example, we show that ZnCO3 (smithsonite) or Zn5(CO3)2(OH)6 (hydrozincite) forms extremely [...] Read more.
We demonstrate a simple strategy to either prevent or enhance hydroxide incorporation in nanocrystalline solid-state metathesis reaction products prepared in ambient environments. As an example, we show that ZnCO3 (smithsonite) or Zn5(CO3)2(OH)6 (hydrozincite) forms extremely rapidly, in less than two minutes, to form crystalline domains of 11 ± 2 nm and 6 ± 2 nm, respectively. The phase selectivity between these nanocrystalline products is dominated by the alkalinity of the hydrated precursor salts, which may in turn affect the availability of carbon dioxide during the reaction. Thus, unlike traditional aqueous precipitation reactions, our solid-state method offers a way to produce hydroxide-free, nanocrystalline products without active pH control. Full article
(This article belongs to the Special Issue New Developments in Nanomaterial Analysis)
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Graphical abstract

Graphical abstract
Full article ">Figure 1
<p>Representative photographs of the paste-like reaction products from (<b>a</b>) Zn(NO<sub>3</sub>)<sub>2</sub>·6H<sub>2</sub>O and NaHCO<sub>3</sub> precursors, which yields ZnCO<sub>3</sub>; and (<b>b</b>) ZnCl<sub>2</sub> + Na<sub>2</sub>CO<sub>3</sub>, which yields Zn<sub>5</sub>(CO<sub>3</sub>)<sub>2</sub>(OH)<sub>6</sub>.</p> Full article ">Figure 2
<p>Representative indexed X-ray diffraction (XRD) data. In (<b>a</b>), all major peaks corresponding to ZnCO<sub>3</sub> (JCPDS 8-0449) are present when starting with Zn(NO<sub>3</sub>)<sub>2</sub> and NaHCO<sub>3</sub> precursors. In (<b>b</b>), the product matches Zn<sub>5</sub>(OH)<sub>6</sub>(CO<sub>3</sub>)<sub>2</sub> (JCPDS 19-1458).</p> Full article ">Figure 3
<p>Representative (<b>a</b>) Fourier transform infrared spectroscopy (FTIR) spectra and (<b>b</b>) Raman spectra for ZnCO<sub>3</sub> (ZC, blue) and Zn<sub>5</sub>(CO<sub>3</sub>)<sub>2</sub>(OH)<sub>6</sub> (HZ, red). Spectra are offset along the vertical axis for clarity.</p> Full article ">Figure 4
<p>(<b>a</b>) ZnCO<sub>3</sub> (ZC, blue) and Zn<sub>5</sub>(CO<sub>3</sub>)<sub>2</sub>(OH)<sub>6</sub> (HZ, red) show one-step decomposition toward the formation of ZnO. The mass loss curves are shown as solid lines, and their derivatives are shown as dashed lines; (b) The decomposition products match ZnO (JCPDS 36-1451). The representative data shown here are for the product from ZC decomposition.</p> Full article ">
1250 KiB  
Article
Nano-Electrochemistry and Nano-Electrografting with an Original Combined AFM-SECM
by Achraf Ghorbal, Federico Grisotto, Julienne Charlier, Serge Palacin, Cédric Goyer, Christophe Demaille and Ammar Ben Brahim
Nanomaterials 2013, 3(2), 303-316; https://doi.org/10.3390/nano3020303 - 17 May 2013
Cited by 12 | Viewed by 10061
Abstract
This study demonstrates the advantages of the combination between atomic force microscopy and scanning electrochemical microscopy. The combined technique can perform nano-electrochemical measurements onto agarose surface and nano-electrografting of non-conducting polymers onto conducting surfaces. This work was achieved by manufacturing an original Atomic [...] Read more.
This study demonstrates the advantages of the combination between atomic force microscopy and scanning electrochemical microscopy. The combined technique can perform nano-electrochemical measurements onto agarose surface and nano-electrografting of non-conducting polymers onto conducting surfaces. This work was achieved by manufacturing an original Atomic Force Microscopy-Scanning ElectroChemical Microscopy (AFM-SECM) electrode. The capabilities of the AFM-SECM-electrode were tested with the nano-electrografting of vinylic monomers initiated by aryl diazonium salts. Nano-electrochemical and technical processes were thoroughly described, so as to allow experiments reproducing. A plausible explanation of chemical and electrochemical mechanisms, leading to the nano-grafting process, was reported. This combined technique represents the first step towards improved nano-processes for the nano-electrografting. Full article
(This article belongs to the Special Issue New Developments in Nanomaterial Analysis)
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Graphical abstract

Graphical abstract
Full article ">Figure 1
<p>(<b>a</b>) Scanning electron microscopy image of the homemade AFM-SECM-electrode after insulation with electrophoretic paint. Beam energy was 15 kV and working distance 31 mm; (<b>b</b>) Scanning electron microscopy image of the tip apex. The apex radius was around 130 nm. Beam energy was 5 kV and working distance 8 mm.</p> Full article ">Figure 2
<p>Steady-state voltammogram of the AFM-SECM-electrode in aqueous solution containing 1 mM ferrocenedimethanol and 0.1 M KH<sub>2</sub>PO<sub>4</sub>. The forward and backward traces are superimposed. The potential scan rate was 50 mV s<sup>−1</sup>.</p> Full article ">Figure 3
<p>Schematic drawing of AFM setups (<b>a</b>) for the AFM-SECM/Agarose system; (<b>b</b>) for the nano-electrografting system.</p> Full article ">Figure 4
<p>Steady-state voltammogram of the PtIr-tip in contact with the agarose surface. Agarose was previously immersed in aqueous solution containing 5 mM ferricyanure and 0.1 M KCl, during 1 h. The potential scan rate was 50 mV s<sup>−1</sup>.</p> Full article ">Figure 5
<p>Scanning electron microscopy image of the homemade AFM-SECM-electrode after collision with the surface during nano-electrochemical grafting attempts. Beam energy was 15 kV and working distance 16 mm.</p> Full article ">Figure 6
<p>(<b>a</b>) Topographic AFM image in tapping mode of the line pattern drawn with the AFM-SECM-electrode on the gold surface with direct aryl diazonium salt/acrylic acid reduction (chronoamperometry: −0.8 V); (<b>b</b>) Horizontal cross section of the electrografted line. Line width and height are about 180 nm and 40 nm, respectively.</p> Full article ">Figure 7
<p>Schematic representation of the electric field between the AFM-SECM-electrode and the substrate.</p> Full article ">Figure 8
<p>A simplified schematic representation of chemical and electrochemical reactions leading to the line grafting. (<b>1</b>) Reduction of the diazonium salt on the substrate to form a polynitrophenylene-like film; (<b>2</b>) Water oxidation at the AFM-SECM-electrode; (<b>3</b>) Concomitant reduction of protons on the substrate and formation of a localized grafted coating onto the top of the primer polynitrophenylene (PNP) film by radical reaction. (<b>3a</b>) Formation of a phenyl radical and reaction with PNP film; (<b>3b</b>) Phenyl radical initiates the first vinylic (plausible) radical polymerization. Reaction of the formed macroradicals with the grafted layer; (<b>3c</b>) Formation of radical monomer, initiation of the second (plausible) vinylic radical polymerization and reaction of the formed macroradicals with the grafted layer.</p> Full article ">Figure 9
<p>Chemical structure of agarose.</p> Full article ">
2569 KiB  
Article
Surface Enhanced Raman Scattering (SERS) Studies of Gold and Silver Nanoparticles Prepared by Laser Ablation
by Gloria M. Herrera, Amira C. Padilla and Samuel P. Hernandez-Rivera
Nanomaterials 2013, 3(1), 158-172; https://doi.org/10.3390/nano3010158 - 1 Mar 2013
Cited by 118 | Viewed by 17418
Abstract
Gold and silver nanoparticles (NPs) were prepared in water, acetonitrile and isopropanol by laser ablation methodologies. The average characteristic (longer) size of the NPs obtained ranged from 3 to 70 nm. 4-Aminobenzebethiol (4-ABT) was chosen as the surface enhanced Raman scattering (SERS) probe [...] Read more.
Gold and silver nanoparticles (NPs) were prepared in water, acetonitrile and isopropanol by laser ablation methodologies. The average characteristic (longer) size of the NPs obtained ranged from 3 to 70 nm. 4-Aminobenzebethiol (4-ABT) was chosen as the surface enhanced Raman scattering (SERS) probe molecule to determine the optimum irradiation time and the pH of aqueous synthesis of the laser ablation-based synthesis of metallic NPs. The synthesized NPs were used to evaluate their capacity as substrates for developing more analytical applications based on SERS measurements. A highly energetic material, TNT, was used as the target compound in the SERS experiments. The Raman spectra were measured with a Raman microspectrometer. The results demonstrate that gold and silver NP substrates fabricated by the methods developed show promising results for SERS-based studies and could lead to the development of micro sensors. Full article
(This article belongs to the Special Issue New Developments in Nanomaterial Analysis)
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Graphical abstract
Full article ">Figure 1
<p>UV-Vis absorption spectra of Au and Ag nanoparticles (NPs) at various irradiation times: (<b>A</b>) absorption spectra of Au NPs; (<b>B</b>) absorption spectra of Ag NPs.</p> Full article ">Figure 2
<p>TEM images of Au and Ag NPs. Au NPs: (<b>A</b>) large spheres with average diameters of 126 ± 39 nm are violet. (<b>B</b>) red colloids have average diameters of 11 ± 4 nm Ag NPs: (<b>C</b>) yellow Ag NPs suspensions have average sizes of 132 ± 5 nm; (<b>D</b>) silver seed-like NP with an average long axis of 5 ± 1 nm are green-gray.</p> Full article ">Figure 3
<p>Surface enhanced Raman scattering (SERS) spectrum of (<b>A</b>) 1 mM BPE in Au NPs at various irradiation times. Raman and SERS spectra were acquired at 785 nm. (<b>B</b>) 1 mM 4-ABT deposited on Ag NPs deposited on Au-coated glass slide at various irradiation times. SERS spectra were acquired at 532 nm.</p> Full article ">Figure 4
<p>NPs suspensions at different pH values of the solvent during synthesis: (<b>A</b>) Au NPs suspensions; (<b>B</b>) Ag NPs suspensions.</p> Full article ">Figure 5
<p>UV-Vis absorption spectra of NPs colloids after synthesis at various pH: (<b>A</b>) Au; (<b>B</b>) Ag.</p> Full article ">Figure 6
<p>pH effect on SERS activity: (<b>A</b>) SERS spectra of 4-ABT on the Au NPs/Au substrate; (<b>B</b>) SERS spectra of 4-ABT on the Ag NPs/Au substrate; (<b>C</b>) TNT SERS spectra on the Au NPs/Au substrate; and (<b>D</b>) SERS spectra of TNT interacting with a Au colloidal suspension, included for comparison.</p> Full article ">Figure 7
<p>SERS spectra of TNT deposited on Au NPs; spectra were taken at 785 nm: (<b>A</b>) NPs were deposited on different substrates (Al film, Au film and quartz); (<b>B</b>) TNT deposited at different concentrations and Al was used as the substrate.</p> Full article ">
2303 KiB  
Article
Kinetic and Surface Study of Single-Walled Aluminosilicate Nanotubes and Their Precursors
by Nicolás Arancibia-Miranda, Mauricio Escudey, Mauricio Molina and María Teresa García-González
Nanomaterials 2013, 3(1), 126-140; https://doi.org/10.3390/nano3010126 - 1 Mar 2013
Cited by 18 | Viewed by 7676
Abstract
The structural and surface changes undergone by the different precursors that are produced during the synthesis of imogolite are reported. The surface changes that occur during the synthesis of imogolite were determined by electrophoretic migration (EM) measurements, which enabled the identification of the [...] Read more.
The structural and surface changes undergone by the different precursors that are produced during the synthesis of imogolite are reported. The surface changes that occur during the synthesis of imogolite were determined by electrophoretic migration (EM) measurements, which enabled the identification of the time at which the critical precursor of the nanoparticles was generated. A critical parameter for understanding the evolution of these precursors is the isoelectric point (IEP), of which variation revealed that the precursors modify the number of active ≡Al-OH and ≡Si-OH sites during the formation of imogolite. We also found that the IEP is displaced to a higher pH level as a consequence of the surface differentiation that occurs during the synthesis. At the same time, we established that the pH of the reaction (pHrx) decreases with the evolution and condensation of the precursors during aging. Integration of all of the obtained results related to the structural and surface properties allows an overall understanding of the different processes that occur and the products that are formed during the synthesis of imogolite. Full article
(This article belongs to the Special Issue New Developments in Nanomaterial Analysis)
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Figure 1

Figure 1
<p>Fourier-Transform Infrared Spectroscopy (FTIR) spectra (<b>a</b>) and X-Ray Diffraction (XRD) patterns (<b>b</b>) of the synthetic products at different aging times: (<b>a</b>) 0 h, (<b>b</b>) 12 h, (<b>c</b>) 24 h, (<b>d</b>) 48 h, (<b>e</b>) 72 h, (<b>f</b>) 96 h, and (<b>g</b>) 120 h.</p> Full article ">Figure 2
<p>Transmission Electron Microscopy (TEM) images of products at different aging times: (<b>a</b>) 0 h, (<b>b</b>) 24 h, (<b>c</b>) 72 h, and (<b>d</b>) 120 h.</p> Full article ">Figure 3
<p>Structural evolution of the precursors formed during the synthesis of imogolite.</p> Full article ">Figure 4
<p>Potentiometric titration curves of imogolite at three different KCl concentrations.</p> Full article ">Figure 5
<p>Schematic representation of the substitutions of –OH groups of the Al precursors by the orthosilicate anion.</p> Full article ">Figure 6
<p>Changes in the reaction pH (∆pH<sub>rx</sub>/Δt) and the isoelectric point (∆IEP/Δt) as functions of the aging time.</p> Full article ">
2371 KiB  
Article
Aqueous Chemical Solution Deposition of Novel, Thick and Dense Lattice-Matched Single Buffer Layers Suitable for YBCO Coated Conductors: Preparation and Characterization
by Vyshnavi Narayanan, Sigelinde Van Steenberge, Petra Lommens and Isabel Van Driessche
Nanomaterials 2012, 2(3), 298-311; https://doi.org/10.3390/nano2030298 - 10 Sep 2012
Cited by 4 | Viewed by 6751
Abstract
In this work we present the preparation and characterization of cerium doped lanthanum zirconate (LCZO) films and non-stoichiometric lanthanum zirconate (LZO) buffer layers on metallic Ni-5% W substrates using chemical solution deposition (CSD), starting from aqueous precursor solutions. La2Zr2O [...] Read more.
In this work we present the preparation and characterization of cerium doped lanthanum zirconate (LCZO) films and non-stoichiometric lanthanum zirconate (LZO) buffer layers on metallic Ni-5% W substrates using chemical solution deposition (CSD), starting from aqueous precursor solutions. La2Zr2O7 films doped with varying percentages of Ce at constant La concentration (La0.5CexZr1−xOy) were prepared as well as non-stoichiometric La0.5+xZr0.5−xOy buffer layers with different percentages of La and Zr ratios. The variation in the composition of these thin films enables the creation of novel buffer layers with tailored lattice parameters. This leads to different lattice mismatches with the YBa2Cu3O7−x (YBCO) superconducting layer on top and with the buffer layers or substrate underneath. This possibility of minimized lattice mismatch should allow the use of one single buffer layer instead of the current complicated buffer architectures such as Ni-(5% W)/LZO/LZO/CeO2. Here, single, crack-free LCZO and non-stoichiometric LZO layers with thicknesses of up to 140 nm could be obtained in one single CSD step. The crystallinity and microstructure of these layers were studied by XRD, and SEM and the effective buffer layer action was studied using XPS depth profiling. Full article
(This article belongs to the Special Issue New Developments in Nanomaterial Analysis)
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Graphical abstract

Graphical abstract
Full article ">Figure 1
<p>X-ray <span class="html-italic">θ</span>–2<span class="html-italic">θ</span> diffraction patterns obtained for (<b>a</b>) Cerium doped lanthanum zirconate (LCZO) buffer layers and (<b>b</b>) Non-stoichiometric lanthanum zirconate (LZO) buffer layers.</p> Full article ">Figure 2
<p>Phi-scan measurements of the (2 2 2) plane of the La<sub>0.50</sub>Ce<sub>0.40</sub>Zr<sub>0.10</sub>O<span class="html-italic"><sub>y</sub></span> and La<sub>0.60</sub>Zr<sub>0.40</sub>O<span class="html-italic"><sub>y</sub></span> buffer layers deposited on top of the Ni-5% W substrate in comparison to the (1 1 1) plane of the Ni-5% W substrate.</p> Full article ">Figure 3
<p>Scanning electron microscope (SEM) image of (<b>a</b>) La<sub>0.50</sub>Ce<sub>0.40</sub>Zr<sub>0.10</sub>O<span class="html-italic"><sub>y</sub></span> on Ni-5% W substrate; (<b>b</b>) La<sub>0.60</sub>Zr<sub>0.40</sub>O<span class="html-italic"><sub>y</sub></span> on Ni-5% W substrate.</p> Full article ">Figure 4
<p>Atomic force microscope (AFM) image of (<b>a</b>) La<sub>0.50</sub>Ce<sub>0.40</sub>Zr<sub>0.10</sub>O<span class="html-italic"><sub>y</sub></span>, (<b>b</b>) La<sub>0.60</sub>Zr<sub>0.40</sub>O<span class="html-italic"><sub>y</sub></span> on Ni-5% W substrate.</p> Full article ">Figure 5
<p>X-ray photoelectron spectroscopy (XPS) depth profile spectrum for La<sub>0.50</sub>Ce<sub>0.40</sub>Zr<sub>0.10</sub>O<span class="html-italic"><sub>y</sub></span> layer.</p> Full article ">Figure 6
<p>XPS overview spectrum of the various elements through the La<sub>0.50</sub>Ce<sub>0.40</sub>Zr<sub>0.10</sub>O<span class="html-italic"><sub>y</sub></span> layer.</p> Full article ">
932 KiB  
Article
Effects of Varied Cleaning Methods on Ni-5% W Substrate for Dip-Coating of Water-based Buffer Layers: An X-ray Photoelectron Spectroscopy Study
by Vyshnavi Narayanan, Els Bruneel, Ruben Hühne and Isabel Van Driessche
Nanomaterials 2012, 2(3), 251-267; https://doi.org/10.3390/nano2030251 - 9 Aug 2012
Cited by 2 | Viewed by 6669
Abstract
This work describes various combinations of cleaning methods involved in the preparation of Ni-5% W substrates for the deposition of buffer layers using water-based solvents. The substrate has been studied for its surface properties using X-ray photoelectron spectroscopy (XPS). The contaminants in the [...] Read more.
This work describes various combinations of cleaning methods involved in the preparation of Ni-5% W substrates for the deposition of buffer layers using water-based solvents. The substrate has been studied for its surface properties using X-ray photoelectron spectroscopy (XPS). The contaminants in the substrates have been quantified and the appropriate cleaning method was chosen in terms of contaminants level and showing good surface crystallinity to further consider them for depositing chemical solution-based buffer layers for Y1Ba2Cu3Oy (YBCO) coated conductors. Full article
(This article belongs to the Special Issue New Developments in Nanomaterial Analysis)
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Graphical abstract

Graphical abstract
Full article ">Figure 1
<p>X-ray photoelectron spectroscopy (XPS) depth profile studies of uncleaned Ni-5% W substrate.</p> Full article ">Figure 2
<p>XPS depth profile studies of Ni peaks in uncleaned substrates.</p> Full article ">Figure 3
<p>Non-wetting droplet of water on top of uncleaned Ni-5% W substrate.</p> Full article ">Figure 4
<p>XPS depth profile studies of Ni-5% W substrate chemically cleaned with etching for 15 min.</p> Full article ">Figure 5
<p>XPS depth profile studies of Ni peaks in substrate chemically cleaned with etching for 15 min (with deconvolution for the presence of NiO).</p> Full article ">Figure 6
<p>Perfectly wetted droplet of water on top of the substrate chemically cleaned with etching for 15 min.</p> Full article ">Figure 7
<p>XPS depth profile studies of Ni-5% W substrate after thermal cleaning.</p> Full article ">Figure 8
<p>XPS depth profile studies of Ni peaks in substrate after thermal cleaning.</p> Full article ">Figure 9
<p>Water droplet on top of a thermally cleaned Ni-5% W substrate.</p> Full article ">Figure 10
<p>XPS depth profile studies of Ni-5% W substrate after thermal cleaning followed by chemical cleaning with etching for 15 min.</p> Full article ">Figure 11
<p>XPS depth profile studies of Ni peaks after thermal cleaning followed by chemical cleaning with etching for 15 min (with deconvolution for the presence of NiO).</p> Full article ">Figure 12
<p>XPS depth profile studies of Ni-5% W substrate after chemical cleaning with etching for 15 min followed by thermal cleaning.</p> Full article ">Figure 13
<p>XPS depth profile studies of Ni peaks after chemical cleaning with etching for 15 min followed by thermal cleaning.</p> Full article ">Figure 14
<p>Reflection high energy electron diffraction (RHEED) pattern of uncleaned and differently cleaned Ni-5% W substrate.</p> Full article ">Figure 15
<p>Comparison between the measured RHEED pattern and a simulation of the diffraction spots using NiO for sample with thermal followed by chemical treatment, whereas the pattern of the chemically followed by thermally treated substrate can be indexed with pure Ni.</p> Full article ">
808 KiB  
Article
Preparation and Characteristics of SiOx Coated Carbon Nanotubes with High Surface Area
by Aeran Kim, Seongyop Lim, Dong-Hyun Peck, Sang-Kyung Kim, Byungrok Lee and Doohwan Jung
Nanomaterials 2012, 2(2), 206-216; https://doi.org/10.3390/nano2020206 - 18 Jun 2012
Cited by 15 | Viewed by 8432
Abstract
An easy method to synthesize SiOx coated carbon nanotubes (SiOx-CNT) through thermal decomposition of polycarbomethylsilane adsorbed on the surface of CNTs is reported. Physical properties of SiOx-CNT samples depending on various Si contents and synthesis conditions are examined [...] Read more.
An easy method to synthesize SiOx coated carbon nanotubes (SiOx-CNT) through thermal decomposition of polycarbomethylsilane adsorbed on the surface of CNTs is reported. Physical properties of SiOx-CNT samples depending on various Si contents and synthesis conditions are examined by X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), nitrogen isotherm, scanning electron microscope (SEM), and transmission electron microscope (TEM). Morphology of the SiOx-CNT appears to be perfectly identical to that of the pristine CNT. It is confirmed that SiOx is formed in a thin layer of approximately 1 nm thickness over the surface of CNTs. The specific surface area is significantly increased by the coating, because thin layer of SiOx is highly porous. The surface properties such as porosity and thickness of SiOx layers are found to be controlled by SiOx contents and heat treatment conditions. The preparation method in this study is to provide useful nano-hybrid composite materials with multi-functional surface properties. Full article
(This article belongs to the Special Issue New Developments in Nanomaterial Analysis)
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Figure 1

Figure 1
<p>Schematic diagram of the SiO<sub>x</sub> coated carbon nanotubes (SiO<sub>x</sub>-CNT) preparation by Polycarbomethylsilane (PS) coating and heat treatment.</p> Full article ">Figure 2
<p>SEM images of (<b>a</b>) pristine CNTs, (<b>b</b>) SC104, (<b>c</b>) SC105, (<b>d</b>) SC107, (<b>e</b>) SC204, and (<b>f</b>) SC304.</p> Full article ">Figure 3
<p>TEM images of (<b>a,b</b>) pristine CNTs, (<b>c,d</b>) SC103, (<b>e,f</b>) SC104, (<b>g,h</b>) SC107.</p> Full article ">Figure 4
<p>(<b>a</b>) Nitrogen isotherm and (<b>b</b>) pore size distribution curve of SiO<sub>x</sub>-CNT samples (48.8 wt % SiO<sub>x</sub>) treated at different temperatures (300 °C, 400 °C, 500 °C).</p> Full article ">Figure 5
<p>Si-2p XPS profiles of PS and SiO<sub>x</sub>-CNT samples.</p> Full article ">Figure 6
<p>C-1s XPS profiles of CNT and SiO<sub>x</sub>-CNT samples.</p> Full article ">Figure 7
<p>XRD profiles of CNT, PS-CNT and the SiO<sub>x</sub>-CNT according to treatment temperature.</p> Full article ">
2314 KiB  
Article
A New Method for Characterization of Natural Zeolites and Organic Nanostructure Using Atomic Force Microscopy
by Domenico Fuoco
Nanomaterials 2012, 2(1), 79-91; https://doi.org/10.3390/nano2010079 - 5 Mar 2012
Cited by 12 | Viewed by 9505
Abstract
In order to study and develop an economical solution to environmental pollution in water, a wide variety of materials have been investigated. Natural zeolites emerge from that research as the best in class of this category. Zeolites are natural materials which are relatively [...] Read more.
In order to study and develop an economical solution to environmental pollution in water, a wide variety of materials have been investigated. Natural zeolites emerge from that research as the best in class of this category. Zeolites are natural materials which are relatively abundant and non biodegradable, economical and serve to perform processes of environmental remediation. This paper contains a full description of a new method to characterize the superficial properties of natural zeolites of exotic provenience (Caribbean Islets) with atomic force microscopy (AFM). AFM works with the simplicity of the optical microscope and the high resolution typical of a transmission electron microscope (TEM). If the sample is conductive, structural information of mesoporous material is obtained using scanning and transmission electron microscopy (SEM and TEM), otherwise the sample has to be processed through the grafitation technique, but this procedure induces errors of topography. Therefore, the existing AFM method, to observe zeolite powders, is made in a liquid cell-head scanner. This work confirms that it is possible to use an ambient air-head scanner to obtain a new kind of microtopography. Once optimized, this new method will allow investigation of organic micelles, a very soft nanostructure of cetyltriammonium bromide (CTAB), upon an inorganic surface such as natural zeolites. The data also demonstrated some correlation between SEM microphotographies and AFM 3D images. Full article
(This article belongs to the Special Issue New Developments in Nanomaterial Analysis)
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Figure 1

Figure 1
<p>Molecular sieves. Microporous molecular structures of some Zeolites are shown into their atomistic representations. Image modified from Atlas of Zeolites.</p> Full article ">Figure 2
<p>Atomic force microscopy (AFM) image obtained by “tapping mode”. Micellar structures are well clear into surface cavity with a medium diameter of a few tens of nanometers (blue arrow). Surface modifications, due to the solvent, build the walls of the cavity (white arrow). Image 1.813 (<bold>A</bold>) shows micellar structures with a medium diameter bigger than those in image 1.814 (<bold>B</bold>) which is attributable to <italic>cloud point </italic>concentration (as explained hereinabove).</p> Full article ">Figure 2
<p>Atomic force microscopy (AFM) image obtained by “tapping mode”. Micellar structures are well clear into surface cavity with a medium diameter of a few tens of nanometers (blue arrow). Surface modifications, due to the solvent, build the walls of the cavity (white arrow). Image 1.813 (<b>A</b>) shows micellar structures with a medium diameter bigger than those in image 1.814 (<b>B</b>) which is attributable to <span class="html-italic">cloud point </span>concentration (as explained hereinabove).</p> Full article ">Figure 2 Cont.
<p>Atomic force microscopy (AFM) image obtained by “tapping mode”. Micellar structures are well clear into surface cavity with a medium diameter of a few tens of nanometers (blue arrow). Surface modifications, due to the solvent, build the walls of the cavity (white arrow). Image 1.813 (<b>A</b>) shows micellar structures with a medium diameter bigger than those in image 1.814 (<b>B</b>) which is attributable to <span class="html-italic">cloud point </span>concentration (as explained hereinabove).</p> Full article ">Figure 3
<p>Solvent effect. The sequence of images shows the scanned area at full scale of 10 µm and its respective morphological structures (<bold>A</bold>); the advancing solvent front (<bold>B</bold>–<bold>D</bold>); the surface completely covered (<bold>E</bold>) and after evaporation (<bold>F</bold>). In <bold>G</bold> is shown the preservation of surface and its relative structures. In <bold>H</bold> is shown the picture with respective processed data during a single measurement.</p> Full article ">Figure 3
<p>Solvent effect. The sequence of images shows the scanned area at full scale of 10 µm and its respective morphological structures (<b>A</b>); the advancing solvent front (<b>B</b>–<b>D</b>); the surface completely covered (<b>E</b>) and after evaporation (<b>F</b>). In <b>G</b> is shown the preservation of surface and its relative structures. In <b>H</b> is shown the picture with respective processed data during a single measurement.</p> Full article ">Figure 3 Cont.
<p>Solvent effect. The sequence of images shows the scanned area at full scale of 10 µm and its respective morphological structures (<b>A</b>); the advancing solvent front (<b>B</b>–<b>D</b>); the surface completely covered (<b>E</b>) and after evaporation (<b>F</b>). In <b>G</b> is shown the preservation of surface and its relative structures. In <b>H</b> is shown the picture with respective processed data during a single measurement.</p> Full article ">Figure 4
<p>Three-Dimensional elaboration of scanned surface. The sample shows in the picture is compressed micronized powder of a zeolite derivative from a Clinoptilolite mineral. (<bold>A</bold>) surface at full scale of 1 µm; (<bold>B</bold>) same surface after the absorption of 150 µL of solvent; (<bold>C</bold>) same surface after the absorption of 150 µL of surfactant solution; (<bold>D</bold>) false color image of xy plane of same zeolite area.</p> Full article ">Figure 4
<p>Three-Dimensional elaboration of scanned surface. The sample shows in the picture is compressed micronized powder of a zeolite derivative from a Clinoptilolite mineral. (<b>A</b>) surface at full scale of 1 µm; (<b>B</b>) same surface after the absorption of 150 µL of solvent; (<b>C</b>) same surface after the absorption of 150 µL of surfactant solution; (<b>D</b>) false color image of xy plane of same zeolite area.</p> Full article ">Figure 4 Cont.
<p>Three-Dimensional elaboration of scanned surface. The sample shows in the picture is compressed micronized powder of a zeolite derivative from a Clinoptilolite mineral. (<b>A</b>) surface at full scale of 1 µm; (<b>B</b>) same surface after the absorption of 150 µL of solvent; (<b>C</b>) same surface after the absorption of 150 µL of surfactant solution; (<b>D</b>) false color image of xy plane of same zeolite area.</p> Full article ">Figure 5
<p>Comparison between AFM and scanning electron microscopy (SEM). <bold>A</bold> and <bold>C</bold> show a photomicrograph highlighting the presence of clusters of granules. In <bold>B</bold> and <bold>D</bold>, the AFM image of the same zeolites matrix powder. All the measures were carried out at the same full scale of 20 µm for better correlation.</p> Full article ">Figure 5
<p>Comparison between AFM and scanning electron microscopy (SEM). <b>A</b> and <b>C</b> show a photomicrograph highlighting the presence of clusters of granules. In <b>B</b> and <b>D</b>, the AFM image of the same zeolites matrix powder. All the measures were carried out at the same full scale of 20 µm for better correlation.</p> Full article ">Figure 5 Cont.
<p>Comparison between AFM and scanning electron microscopy (SEM). <b>A</b> and <b>C</b> show a photomicrograph highlighting the presence of clusters of granules. In <b>B</b> and <b>D</b>, the AFM image of the same zeolites matrix powder. All the measures were carried out at the same full scale of 20 µm for better correlation.</p> Full article ">Figure 6
<p>Atomic Force Microscopy. Schematic diagram of AFM and three different AFM operating modes. In this paper Tapping and Contact Modes are used.</p> Full article ">

Review

Jump to: Research

1072 KiB  
Review
Porous Copolymer Resins: Tuning Pore Structure and Surface Area with Non Reactive Porogens
by Mohamed H. Mohamed and Lee D. Wilson
Nanomaterials 2012, 2(2), 163-186; https://doi.org/10.3390/nano2020163 - 6 Jun 2012
Cited by 55 | Viewed by 12290
Abstract
In this review, the preparation of porous copolymer resin (PCR) materials via suspension polymerization with variable properties are described by tuning the polymerization reaction, using solvents which act as porogens, to yield microporous, mesoporous, and macroporous materials. The porogenic properties of solvents are [...] Read more.
In this review, the preparation of porous copolymer resin (PCR) materials via suspension polymerization with variable properties are described by tuning the polymerization reaction, using solvents which act as porogens, to yield microporous, mesoporous, and macroporous materials. The porogenic properties of solvents are related to traditional solubility parameters which yield significant changes in the surface area, porosity, pore volume, and morphology of the polymeric materials. The mutual solubility characteristics of the solvents, monomer units, and the polymeric resins contribute to the formation of porous materials with tunable pore structures and surface areas. The importance of the initiator solubility, surface effects, the temporal variation of solvent composition during polymerization, and temperature effects contribute to the variable physicochemical properties of the PCR materials. An improved understanding of the factors governing the mechanism of formation for PCR materials will contribute to the development and design of versatile materials with tunable properties for a wide range of technical applications. Full article
(This article belongs to the Special Issue New Developments in Nanomaterial Analysis)
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Figure 1

Figure 1
<p>Schematic representation of pore formation in poly(DVB) resins: (<b>A</b>) using a “bad” solvent porogen; (<b>B</b>) using a thermodynamically “good” solvent porogen; and (<b>C</b>) using a mixture of “good” and “bad” solvent porogen as co-porogens. (Reprinted (adapted) with permission from [<a href="#B18-nanomaterials-02-00163" class="html-bibr">18</a>]. Copyright 2004 American Chemical Society). NB: The pores are of different sizes and are not drawn according to scale, as shown below.</p> Full article ">Figure 2
<p>A three-dimensional plot of the three solubility parameter (SP) contributions <span class="html-italic">i.e.</span>, dispersion forces (<span class="html-italic">δ<sub>d</sub></span>), dipolar interactions (<span class="html-italic">δ<sub>p</sub></span>), and H-bond capacity (<span class="html-italic">δ<sub>h</sub></span>), to the total SP (<span class="html-italic">δ<sub>T</sub></span>). The tri-point represents a hypothetical polymer. Interaction radius is the shortest distance between the tri-point and the solvent.</p> Full article ">Figure 3
<p>Spherical region characterizing poly(3-hydroxybutyrate) (PHB) solubility in various solvents: (<b>a</b>) the outline of the region; and (<b>b</b>) the inside of the region. The shapes indicating the solvents depend on whether the point is located inside or outside the solubility region: square and circle represent a position outside the region (<sup>j</sup>R &lt; <sup>ij</sup>R) and one inside the region (<sup>j</sup>R &gt; <sup>ij</sup>R), respectively. <sup>ij</sup>R, distance of solvents at position (δ<sub>d</sub>, δ<sub>p,</sub> δ<sub>h</sub> ) from center of solubility sphere for PHB, calculated from Equation (4). (Reprinted from [<a href="#B45-nanomaterials-02-00163" class="html-bibr">45</a>], Copyright 1999, with permission from Elsevier).</p> Full article ">Figure 4
<p>Pore size distribution of porous HM-poly(2-hydroxyethyl methacrylate-<span class="html-italic">co</span>-methyl methacrylate), HS - poly(2-hydroxyethyl methacrylate-<span class="html-italic">co</span>-styrene), and HN-poly(2-hydroxyethyl methacrylate-<span class="html-italic">co</span>-<span class="html-italic">N</span>-vinyl-2-pyrrolidone) particles. r is the ratio of monomer to porogen. PSD shifts to the right side when r increases. (Reprinted (adapted) with permission from [<a href="#B46-nanomaterials-02-00163" class="html-bibr">46</a>]. Copyright 2008 American Chemical Society).</p> Full article ">Figure 5
<p>Plot of the surface area of macropores (%) <span class="html-italic">vs.</span> PPG-1000 co-porogen content (vol %) in the dry state for poly(DVB) resins. (Reprinted (adapted) with permission from [<a href="#B18-nanomaterials-02-00163" class="html-bibr">18</a>]. Copyright 2004 American Chemical Society).</p> Full article ">Figure 6
<p>Plot of surface area (N<sub>2</sub> BET) <span class="html-italic">vs.</span> PPG-1000 co-porogen content (vol %) for dry state poly(DVB) resins showing a maximum ~6 vol% PPG-1000. (Reprinted (adapted) with permission from [<a href="#B18-nanomaterials-02-00163" class="html-bibr">18</a>]. Copyright 2004 American Chemical Society).</p> Full article ">Figure 7
<p>Variation in the total BET surface area (●) and micropore surface area (о) of trimethylolpropane trimethacrylate as a function of the CO<sub>2</sub> final pressure. (Reprinted (adapted) with permission from [<a href="#B30-nanomaterials-02-00163" class="html-bibr">30</a>]. Copyright 2004 American Chemical Society).</p> Full article ">Figure 8
<p>Variation of the percentage of micropore surface area (<span class="html-italic">i.e</span>., micropore area/total surface area × 100) of trimethylolpropane trimethacrylate as a function of the final pressure of CO<sub>2</sub>. (Reprinted (adapted) with permission from [<a href="#B30-nanomaterials-02-00163" class="html-bibr">30</a>]. Copyright 2004 American Chemical Society).</p> Full article ">Figure 9
<p><b>Group 1</b>: SEM micrographs of the resins prepared with 150 % dilution using <span class="html-italic">n</span>-heptane/toluene as a diluent system at variable 2-vinyl pyridine/styrene/divinylbenzene ratios; (<b>a</b>) 30/4030;(<b>b</b>) 40/30/30 and (<b>c</b>) 50/20/30. <b>Group 2</b>: SEM micrographs of the resins synthesized with 100% dilution using <span class="html-italic">n</span>-heptane/ethyl acetate as a diluent system at 2-vinyl pyridine/styrene/divinylbenzene ratios; (<b>a</b>) 30/4030;(<b>b</b>) 40/30/30 and (<b>c</b>) 50/20/30. (Reprinted from [<a href="#B48-nanomaterials-02-00163" class="html-bibr">48</a>], Copyright 2004, with permission from Elsevier).</p> Full article ">
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