scholarly journals Microstructural evidence of the toughening mechanisms of polyurethane reinforced with halloysite nanotubes under high strain-rate tensile loading

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Rafaela Aguiar ◽  
Ronald E. Miller ◽  
Oren E. Petel
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Spall Strength ◽  
Microstructural Characterization ◽  
Halloysite Nanotubes ◽  
Force Microscopy ◽  
Tensile Response ◽  
Show Evidence ◽  
Fracture Character ◽  
Scanning Electron

AbstractIn this study, we have investigated the relationship between the spherulitic morphology and the dynamic tensile response of polyurethane reinforced with Halloysite nanotubes (HNTs). The polyurethane prepolymer is partially silane end-capped and filled with only 0.8 wt.% of acid-treated Halloysite nanotubes. The resultant nanocomposite material presents a 35% higher spall strength compared to the neat polyurethane and 21% higher fracture toughness. We show evidence that the HNTs are not the toughening phase in the nanocomposite, but rather it is their influence on the resultant spherulitic structures which alters the polymer microstructure and leads to a tougher dynamic response. Microstructural characterization is performed via Scanning Electron Microscopy, Atomic Force Microscopy and Field Emission Scanning Electron Microscopy, and crystallinity examination via X-ray diffraction. The spherulitic structures present a brittle fracture character, while the interspherulitic regions are more ductile and show large deformation. The nanocomposite presents a finer and more rigid spherulitic structure, and a more energy dissipative fracture mechanism characterized by a rougher fracture surface with highly deformed interspherulitic regions.

Photoelectric Response of Self Assembled Films of Bacterio-Rhodopsin Purple Membrane Integrated on Silicon

2003 ◽  
Vol 774 ◽  
Author(s):  
D. Ricceri ◽  
G. Scicolone ◽  
O. Di Marco ◽  
S. Conoci ◽  
B. Pignataro ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Light Exposure ◽  
Scanning Force Microscopy ◽  
Purple Membrane ◽  
Morphological Properties ◽  
Force Microscopy ◽  
Scanning Force ◽  
Scanning Electron ◽  
Tungsten Lamp

AbstractBacterio-rhodopsin purple membrane (PM) thin films have been prepared by selfassembling (SA) technique. Morphological properties of the layers were inspected by Scanning Electron Microscopy (SEM) and Scanning Force Microscopy (SFM) highlighting the presence of densely packed PM films. Reflectance Uv-vis spectra on these films revealed the typical bR absorption at 570 nm. By using a tungsten lamp illuminations (250-350 mW) chopped at 0.5Hz, photoelectric responses were detected. Differential (light-on and light-off) photocurrent signals of up to 1 μA/cm2 were obtained upon light exposure.

scholarly journals Corrosion Behavior and Mechanical Properties of a Nanocomposite Superhydrophobic Coating

Coatings ◽  
2021 ◽  
Vol 11 (6) ◽  
pp. 652
Author(s):  
Divine Sebastian ◽  
Chun-Wei Yao ◽  
Lutfun Nipa ◽  
Ian Lian ◽  
Gary Twu
Keyword(s):  
Electron Microscopy ◽  
Mechanical Properties ◽  
Scanning Electron Microscopy ◽  
Atomic Force Microscopy ◽  
Nanocomposite Coating ◽  
Superhydrophobic Coating ◽  
Force Microscopy ◽  
Atomic Force ◽  
Microscopy Images ◽  
Scanning Electron

In this work, a mechanically durable anticorrosion superhydrophobic coating is developed using a nanocomposite coating solution composed of silica nanoparticles and epoxy resin. The nanocomposite coating developed was tested for its superhydrophobic behavior using goniometry; surface morphology using scanning electron microscopy and atomic force microscopy; elemental composition using energy dispersive X-ray spectroscopy; corrosion resistance using atomic force microscopy; and potentiodynamic polarization measurements. The nanocomposite coating possesses hierarchical micro/nanostructures, according to the scanning electron microscopy images, and the presence of such structures was further confirmed by the atomic force microscopy images. The developed nanocomposite coating was found to be highly superhydrophobic as well as corrosion resistant, according to the results from static contact angle measurement and potentiodynamic polarization measurement, respectively. The abrasion resistance and mechanical durability of the nanocomposite coating were studied by abrasion tests, and the mechanical properties such as reduced modulus and Berkovich hardness were evaluated with the aid of nanoindentation tests.

Comparative Study of Field Emission-Scanning Electron Microscopy and Atomic Force Microscopy to Assess Self-assembled Monolayer Coverage on Any Type of Substrate

1999 ◽  
Vol 5 (6) ◽  
pp. 413-419 ◽  
Author(s):  
Bernardo R.A. Neves ◽  
Michael E. Salmon ◽  
Phillip E. Russell ◽  
E. Barry Troughton
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Atomic Force Microscopy ◽  
Comparative Study ◽  
Field Emission ◽  
Self Assembled Monolayer ◽  
Force Microscopy ◽  
Atomic Force ◽  
Self Assembled ◽  
Scanning Electron

Abstract: In this work, we show how field emission–scanning electron microscopy (FE-SEM) can be a useful tool for the study of self-assembled monolayer systems. We have carried out a comparative study using FE-SEM and atomic force microscopy (AFM) to assess the morphology and coverage of self-assembled monolayers (SAM) on different substrates. The results show that FE-SEM images present the same qualitative information obtained by AFM images when the SAM is deposited on a smooth substrate (e.g., mica). Further experiments with rough substrates (e.g., Al grains on glass) show that FE-SEM is capable of unambiguously identifying SAMs on any type of substrate, whereas AFM has significant difficulties in identifying SAMs on rough surfaces.

scholarly journals Структура и механизмы образования наноразмерных пленок примесного металла кобальта и никеля в монокристаллах LiF и MgF-=SUB=-2-=/SUB=-

2021 ◽  
Vol 63 (9) ◽  
pp. 1340
Author(s):  
Н.А. Иванов ◽  
С.А. Небогин ◽  
С.С. Колесников ◽  
Л.И. Брюквина
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Etch Pits ◽  
Force Microscopy ◽  
Thermal Etching ◽  
Air Atmosphere ◽  
Atomic Force ◽  
Residual Air ◽  
Scanning Electron ◽  
Cobalt And Nickel

It is investigated the thermal etching of LiF and MgF2 crystals with cobalt and nickel impurities by means of scanning electron microscopy and atomic force microscopy with using decorating. It is shown that impurity inclusions leave the crystal from dislocations. The differences between of thermal etching in vacuum and air atmosphere take place. The crystallographic oriented terraced etch pits are formed after exit of impurities from dislocations. The square thermal etch pits are formed after thermal etching at 750°C in air. The surface impurity nanoscale film is formed at thermal etching. The oxidation of surface impurities observed at thermal etching in air atmosphere or in residual air atmosphere.

scholarly journals Characterization of dentin morphology after application of ozone and sodium ascorbate by scanning electron microscopy and atomic force microscopy

RSBO ◽  
2021 ◽  
Vol 17 (2) ◽  
pp. 85-91
Author(s):  
João Batista de Souza ◽  
Daniel Rodrigues ◽  
Paula Cicília Faquim Rodrigues ◽  
Lawrence Gonzaga Lopes ◽  
Tainah Costa Firmiano ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Atomic Force Microscopy ◽  
Phosphoric Acid ◽  
Sodium Ascorbate ◽  
Acid Etching ◽  
Force Microscopy ◽  
Atomic Force ◽  
Group 3 ◽  
Scanning Electron

The aim of this study was to evaluate dentin morphology after ozone gas and sodium ascorbate application by the Scanning Electron Microscopy (SEM) and Atomic Force Microscopy (AFM) images. Material and methods: Seven freshly extracted human third molars were sectioned perpendicularly to the tooth long axis, 3mm above the cementoenamel junction and other section above the first. Dentin slices were obtained, 2 mm thickness, then the slices were sectioned vertically and horizontally into four equal parts, resulting in 28 samples. These were divided in 4 groups (n=7): (G1) phosphoric acid – control; (G2) ozone + phosphoric acid; (G3) phosphoric acid + ozone; and (G4) ozone + sodium ascorbate + phosphoric acid. Dentin morphology of six samples of each groupwas evaluated by SEM and one by AFM. Results: In Groups 2 and 4 there was a change in the effectiveness of acid etching in terms of removing the smear layer. In Group 3 there was a change in the dentin microstructure, which can be a harmful factor regarding the bond strength of adhesive agents. Conclusion: After the qualitative analysis, the application sequences of ozone, phosphoric acid etching and sodium ascorbate application generated differences in the dentinmorphology by SEM and AFM. Sodium ascorbate decreased the ozone effect before the acid etching but did not eliminate it.

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