scholarly journals Temperature Effects on the HOPG Intercalation Process

2019 ◽  
Vol 4 (1) ◽  
pp. 23 ◽  
Author(s):  
Gianlorenzo Bussetti ◽  
Rossella Yivlialin ◽  
Claudio Goletti ◽  
Maurizio Zani ◽  
Lamberto Duò
Keyword(s):  
Common Procedure ◽  
Force Microscopy ◽  
Carbon Dissolution ◽  
Atomic Force ◽  
Defect Sites ◽  
Graphite Intercalation ◽  
Increasing Temperature ◽  
Chemical Strategies

Graphite intercalation via chemical strategies is a common procedure to delaminate stratified crystals and obtain a suspension of graphene flakes. The intercalation mechanism at the molecular level is still under investigation in view of enhancing graphene production and reducing damage to the original pristine crystal. The latter, in particular, can undergo surface detriment due to both blister evolution and carbon dissolution. The role of the electrolyte temperature in this process has never been investigated. Here, by using an in-situ atomic force microscopy (AFM) apparatus, we explore surface morphology changes after the application of fast cyclic-voltammetries at 343 K, in view of de-coupling the crystal swelling phenomenon from the other electrochemical processes. We find that blisters do not evolve as a consequence of the increasing temperature, while the quality of the graphite surface becomes significantly worse, due to the formation of some adsorbates on possible defect sites of the electrode surface. Our results suggest that the chemical baths used in graphite delamination must be carefully monitored in temperature for avoiding undesired electrode detriment.

scholarly journals Nucleation and Growth of Supported Metal Clusters at Defect Sites on Mgo and NaCl (001) Surfaces: The Cases of Pd and Ag

1999 ◽  
Vol 570 ◽  
Author(s):  
J. A. Venables ◽  
G. Haas ◽  
H. Brune ◽  
J.H. Harding
Keyword(s):  
Deposition Temperature ◽  
Metal Clusters ◽  
Variable Temperature ◽  
Nucleation And Growth ◽  
Force Microscopy ◽  
Atomic Force ◽  
Defect Sites ◽  
Wide Range ◽  
Adsorption Surface

ABSTRACTNucleation and growth of metal clusters at defect sites is discussed in terms of rate equation models, which are applied to the cases of Pd and Ag on MgO(001) and NaCl(001) surfaces. Pd/MgO has been studied experimentally by variable temperature atomic force microscopy (AFM). The island density of Pd on Ar-cleaved surfaces was determined in-situ by AFM for a wide range of deposition temperature and flux, and stays constant over a remarkably wide range of parameters; for a particular flux, this plateau extends from 200 K ≤ T ≤ 600 K, but at higher temperatures the density decreases. The range of energies for defect trapping, adsorption, surface diffusion and pair binding are deduced, and compared with earlier data for Ag on NaCl, and with recent calculations for these metals on both NaCl and MgO

Probing Crystallization of Calcium Oxalate Monohydrate and the Role of Macromolecule Additives with in Situ Atomic Force Microscopy

Langmuir ◽  
2004 ◽  
Vol 20 (20) ◽  
pp. 8587-8596 ◽  
Author(s):  
Taesung Jung ◽  
Xiaoxia Sheng ◽  
Chang Kyun Choi ◽  
Woo-Sik Kim ◽  
Jeffrey A. Wesson ◽  
...  
Keyword(s):  
Atomic Force Microscopy ◽  
Calcium Oxalate ◽  
Calcium Oxalate Monohydrate ◽  
Force Microscopy ◽  
Atomic Force

Multi-Scale Structure of the Pinctada Mother of Pearl: Demonstration of a Continuous and Oriented Organic Framework in a Natural Ceramic

2005 ◽  
Vol 284-286 ◽  
pp. 705-708 ◽  
Author(s):  
Marthe Rousseau ◽  
Xavier Bourrat ◽  
Philippe Stempflé ◽  
Marcel Brendlé ◽  
Evelyne Lopez
Keyword(s):  
Cross Sections ◽  
Organic Matrix ◽  
Phase Imaging ◽  
Force Microscopy ◽  
Multi Scale ◽  
Atomic Force ◽  
Intermittent Contact ◽  
Organic Framework

Sheet nacre is a promising natural bioceramic, which consists on the internal lustrous “mother of pearl” layer of many molluscan shells, e.g. Pinctada, our model. The aim of this work is to study the structure of the flat polygonal tablets of nacre, in order to understand the multi-scale organization of this composite material and the role of the organic template during the growth of the biocrystal. We studied the organic matrix, in situ with techniques such as darkfield transmission electronic microscopy (TEM) on small cross-sections of nacre of Pinctada maxima, or intermittent-contact atomic force microscopy coupled with phase imaging on samples of nacre of Pinctada margaritifera polished parallel to the surface of the tablets. In this study, we demonstrate the continuity of the organic framework and the crystallographic orientation in the biocrystal at 2 relevant levels : nano- and micro-scale.

scholarly journals Mechanisms of antiwear tribofilm growth revealed in situ by single-asperity sliding contacts

Science ◽  
2015 ◽  
Vol 348 (6230) ◽  
pp. 102-106 ◽  
Author(s):  
N. N. Gosvami ◽  
J. A. Bares ◽  
F. Mangolini ◽  
A. R. Konicek ◽  
D. G. Yablon ◽  
...  
Keyword(s):  
Elevated Temperatures ◽  
Critical Role ◽  
Force Microscopy ◽  
Thermally Activated ◽  
Single Asperity ◽  
Atomic Force ◽  
Sliding Interfaces ◽  
Lubricant Base Stock

Zinc dialkyldithiophosphates (ZDDPs) form antiwear tribofilms at sliding interfaces and are widely used as additives in automotive lubricants. The mechanisms governing the tribofilm growth are not well understood, which limits the development of replacements that offer better performance and are less likely to degrade automobile catalytic converters over time. Using atomic force microscopy in ZDDP-containing lubricant base stock at elevated temperatures, we monitored the growth and properties of the tribofilms in situ in well-defined single-asperity sliding nanocontacts. Surface-based nucleation, growth, and thickness saturation of patchy tribofilms were observed. The growth rate increased exponentially with either applied compressive stress or temperature, consistent with a thermally activated, stress-assisted reaction rate model. Although some models rely on the presence of iron to catalyze tribofilm growth, the films grew regardless of the presence of iron on either the tip or substrate, highlighting the critical role of stress and thermal activation.

scholarly journals Ultrafine metal-polymer catalysts based on polyconjugated systems for Fisher–Tropsch synthesis

2020 ◽  
Vol 92 (6) ◽  
pp. 977-984
Author(s):  
Mayya V. Kulikova ◽  
Albert B. Kulikov ◽  
Alexey E. Kuz’min ◽  
Anton L. Maximov
Keyword(s):  
Tropsch Synthesis ◽  
X Ray Diffraction ◽  
Fischer Tropsch ◽  
Force Microscopy ◽  
Composite Catalysts ◽  
Fe Catalyst ◽  
Atomic Force ◽  
And Function ◽  
Metal Polymer

AbstractFor previously studied Fischer–Tropsch nanosized Fe catalyst slurries, polymer compounds with or without polyconjugating structures are used as precursors to form the catalyst nanomatrix in situ, and several catalytic experiments and X-ray diffraction and atomic force microscopy measurements are performed. The important and different roles of the paraffin molecules in the slurry medium in the formation and function of composite catalysts with the two types of aforementioned polymer matrices are revealed. In the case of the polyconjugated polymers, the alkanes in the medium are “weakly” coordinated with the metal-polymer composites, which does not affect the effectiveness of the polyconjugated polymers. Otherwise, alkane molecules form a “tight” surface layer around the composite particles, which create transport complications for the reagents and products of Fischer-Tropsch synthesis and, in some cases, can change the course of the in situ catalyst formation.

Atomic force microscopy of in situ deformed nickel thin films

1999 ◽  
Vol 353 (1-2) ◽  
pp. 194-200 ◽  
Author(s):  
C. Coupeau ◽  
J.F. Naud ◽  
F. Cleymand ◽  
P. Goudeau ◽  
J. Grilhé
Keyword(s):  
Thin Films ◽  
Atomic Force Microscopy ◽  
Force Microscopy ◽  
Nickel Thin Films ◽  
Atomic Force

scholarly journals Degradation Mechanism of Porous Metal-Organic Frameworks by In Situ Atomic Force Microscopy

Nanomaterials ◽  
2021 ◽  
Vol 11 (3) ◽  
pp. 722
Author(s):  
Ioanna Christodoulou ◽  
Tom Bourguignon ◽  
Xue Li ◽  
Gilles Patriarche ◽  
Christian Serre ◽  
...  
Keyword(s):  
Drug Delivery ◽  
Degradation Mechanism ◽  
Metal Organic Frameworks ◽  
Porous Metal ◽  
Force Microscopy ◽  
Atomic Force ◽  
Metal Organic ◽  
The Media ◽  
Ph Conditions

In recent years, Metal-Organic Frameworks (MOFs) have attracted a growing interest for biomedical applications. The design of MOFs should take into consideration the subtle balance between stability and biodegradability. However, only few studies have focused on the MOFs’ stability in physiological media and their degradation mechanism. Here, we investigate the degradation of mesoporous iron (III) carboxylate MOFs, which are among the most employed MOFs for drug delivery, by a set of complementary methods. In situ AFM allowed monitoring with nanoscale resolution the morphological, dimensional, and mechanical properties of a series of MOFs in phosphate buffer saline and in real time. Depending on the synthetic route, the external surface presented either well-defined crystalline planes or initial defects, which influenced the degradation mechanism of the particles. Moreover, MOF stability was investigated under different pH conditions, from acidic to neutral. Interestingly, despite pronounced erosion, especially at neutral pH, the dimensions of the crystals were unchanged. It was revealed that the external surfaces of MOF crystals rapidly respond to in situ changes of the composition of the media they are in contact with. These observations are of a crucial importance for the design of nanosized MOFs for drug delivery applications.

In Situ Characterization of the Mechanical Behavior of Gecko's Spatulae by Atomic Force Microscopy

2013 ◽  
Vol 22 ◽  
pp. 85-93
Author(s):  
Shuang Yi Liu ◽  
Min Min Tang ◽  
Ai Kah Soh ◽  
Liang Hong
Keyword(s):  
Mechanical Behavior ◽  
Hierarchical Level ◽  
Intrinsic Properties ◽  
In Situ Characterization ◽  
Force Microscopy ◽  
Atomic Force ◽  
Theoretical Predictions ◽  
Multi Mode

In-situ characterization of the mechanical behavior of geckos spatula has been carried out in detail using multi-mode AFM system. Combining successful application of a novel AFM mode, i.e. Harmonix microscopy, the more detail elastic properties of spatula is brought to light. The results obtained show the variation of the mechanical properties on the hierarchical level of a seta, even for the different locations, pad and stalk of the spatula. A model, which has been validated using the existing experimental data and phenomena as well as theoretical predictions for geckos adhesion, crawling and self-cleaning of spatulae, is proposed in this paper. Through contrast of adhesive and craw ability of the gecko on the surfaces with different surface roughness, and measurement of the surface adhesive behaviors of Teflon, the most effective adhesion of the gecko is more dependent on the intrinsic properties of the surface which is adhered.

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