Alumina-Silicate Glass Interfacial Properties Probed by Micromechanical Testing Techniques

1995 ◽  
Vol 401 ◽  
Author(s):  
Andrey V. Zagrebelnya ◽  
John C. Nelson ◽  
Erica T. Lilleodden ◽  
Sundar Ramamurthy ◽  
C. Barry Carter
Keyword(s):  
Force Microscopy ◽  
Operating Modes ◽  
Deformation Structures ◽  
Atomic Force ◽  
Afm Imaging ◽  
Before And After ◽  
Calcium Aluminosilicate ◽  
Testing Techniques ◽  
Force Displacement

AbstractMicromechanical properties of the interfaces between alumina and calcium-aluminosilicate (CAS) glasses were tested using various micro/nanoindentation techniques. The interfaces were produced by depositing continuous films of anorhtite (CaAl2Si2O8) onto single-crstal α-Al2O3 of two crystallographic orientations by pulsed-laser deposition (PLD).The mechanical behavior of the interfaces was examined using two different depthsensing indentation instruments. Three types of tests, namely indentation, microscratch, and in-situ indentation combined with atomic force microscopy (AFM) imaging were conducted using different operating modes. The deformation behavior observed for the indentations and microscratches has been correlated with irregularities observed in the load-displacement curves. In the first two cases, scanning electron microscopy (SEM) has been used to characterize the deformation structures associated with the deformed regions. The in-situ experiments allow force-displacement measurements and AFM imaging immediately before and after indentation. The preindent and postindent morphology of the surface could then be characterized.

Effect of Glass Composition on Mechanical Properties of Interfaces Between Alumina and Silicate Glass

1996 ◽  
Vol 458 ◽  
Author(s):  
Andrey V. Zagrebelny ◽  
Erica T. Lilleodden ◽  
C. Barry Carter
Keyword(s):  
Mechanical Properties ◽  
Single Crystal ◽  
Silicate Glass ◽  
Glass Composition ◽  
Depth Sensing ◽  
Force Microscopy ◽  
Atomic Force ◽  
Afm Imaging ◽  
Force Displacement

ABSTRACTInterfaces between glass and crystalline grains have been examined using a thin-film geometry which allows the use of newly developed experimental methods for micromechanical testing of interfaces. In this approach, continuous films of thicknesses ranging 100–200 nm of anorthite (CaAl2Si2O8), celsian (BaAl2Si2O8), and monticellite (CaMgSiO4) are deposited onto single-crystal Al2O3 (α-structure) surfaces of different crystallographic orientations by pulsed-laser deposition (PLD).Mechanical properties such as hardness, stiffness, and reduced Young's modulus were probed with a newly developed high-resolution depth-sensing indentation instrument. Emphasis has been placed on examining how changes in the glass composition will affect the mechanical properties of the single-crystal Al2O3/silicate-glass interfaces. The indentation data obtained from these experiments correlate directly to the morphology of the deformed regions imaged with atomic force microscopy (AFM). Nanomechanical tests combined with AFM imaging of the deformed regions allow force-displacement measurements and in-situ imaging of the same regions of the specimen before and immediately after indentation. This new technique eliminates the uncertainty of locating the indenter after unloading.

scholarly journals In Situ AFM Imaging of Adsorption Kinetics of DPPG Liposomes: A Quantitative Analysis of Surface Roughness

2019 ◽  
Vol 25 (3) ◽  
pp. 798-809
Author(s):  
Andreia A. Duarte ◽  
Joaquim T. Marquês ◽  
Francisco Brasil ◽  
Ana S. Viana ◽  
Pedro Tavares ◽  
...  
Keyword(s):  
Surface Roughness ◽  
Hydrodynamic Diameter ◽  
Supported Lipid Bilayer ◽  
Force Microscopy ◽  
Atomic Force ◽  
Power Spectral ◽  
Afm Imaging ◽  
Density Analysis ◽  
Power Spectral Density Analysis

AbstractThe adsorption of intact liposomes on surfaces is of great importance for the development of sensors and drug delivery systems and, also, strongly dependent on the surface roughness where the liposomes are adsorbed. In this paper, we analyzed, by using atomic force microscopy in liquid, the evolution of the morphology of gold surfaces and of poly(allylamine hydrochloride) (PAH) surfaces with different roughness during the adsorption of liposomes prepared with the synthetic phospholipid 1,2-dipalmitoyl-sn-glycero-3-[phospho-rac-(1-glycerol)]. Our results reveal the following. On smooth surfaces of Au only and Au with PAH, the liposomes open and deploy on the substrate, creating a supported-lipid bilayer, with the opening process being faster on the Au/PAH surface. On rough substrates of Au coated with polyelectrolyte multilayers, the liposomes were adsorbed intact on the surface. This was corroborated by power spectral density analysis that demonstrates the presence of superstructures with an average lateral size of 43 and 87 nm, in accordance with two and four times the mean liposome hydrodynamic diameter of about 21 nm. In addition, this work presents an adequate and effective methodology for analysis of adsorption phenomena of liposomes on rough surfaces.

scholarly journals Choosing a Cantilever for In Situ Atomic Force Microscopy

2003 ◽  
Vol 11 (2) ◽  
pp. 42-43
Author(s):  
John T. Woodward
Keyword(s):  
Biological Sciences ◽  
Atomic Force Microscopy ◽  
Biological Samples ◽  
Contact Mode ◽  
Force Microscopy ◽  
Atomic Force ◽  
Afm Imaging ◽  
Interesting Discussion ◽  
Intermittent Contact

What is the best cantilever for intermittent contact mode (often called Tapping Mode™) atomic force microscope (AFM) imaging under water? This is a question I hear often and one that recently generated some interesting discussion on an AFM newsgroup (more on the newsgroup below). The ability of the AFM to image samples En physiologically relevant environments has made it a popular technique in the biological sciences. However, because scanning the AFM tip in contact mode easily perturbs many biological samples, it was the advent of intermittent contact modes that lead to AFM's widespread use in biology.

scholarly journals Structure of Intracellular Mature Vaccinia Virus Visualized by In Situ Atomic Force Microscopy

2003 ◽  
Vol 77 (11) ◽  
pp. 6332-6340 ◽  
Author(s):  
A. J. Malkin ◽  
A. McPherson ◽  
P. D. Gershon
Keyword(s):  
Atomic Force Microscopy ◽  
Vaccinia Virus ◽  
Helical Surface ◽  
Force Microscopy ◽  
Virus Particles ◽  
The Core ◽  
Atomic Force ◽  
Afm Imaging ◽  
Intact Core

ABSTRACT Vaccinia virus, the basis of the smallpox vaccine, is one of the largest viruses to replicate in humans. We have used in situ atomic force microscopy (AFM) to directly visualize fully hydrated, intact intracellular mature vaccinia virus (IMV) virions and chemical and enzymatic treatment products thereof. The latter included virion cores, core-enveloping coats, and core substructures. The isolated coats appeared to be composed of a highly cross-linked protein array. AFM imaging of core substructures indicated association of the linear viral DNA genome with a segmented protein sheath forming an extended ∼16-nm-diameter filament with helical surface topography; enclosure of this filament within a 30- to 40-nm-diameter tubule which also shows helical topography; and enclosure of the folded, condensed 30- to 40-nm-diameter tubule within the core by a wall covered with peg-like projections. Proteins observed attached to the 30- to 40-nm-diameter tubules may mediate folding and/or compaction of the tubules and/or represent vestiges of the core wall and/or pegs. An accessory “satellite domain” was observed protruding from the intact core. This corresponded in size to isolated 70- to 100-nm-diameter particles that were imaged independently and might represent detached accessory domains. AFM imaging of intact virions indicated that IMV underwent a reversible shrinkage upon dehydration (as much as 2.2- to 2.5-fold in the height dimension), accompanied by topological and topographical changes, including protrusion of the satellite domain. As shown here, the chemical and enzymatic dissection of large, asymmetrical virus particles in combination with in situ AFM provides an informative complement to other structure determination techniques.

scholarly journals High‐Speed Atomic Force Microscopy: Large‐Range HS‐AFM Imaging of DNA Self‐Assembly through In Situ Data‐Driven Control (Small Methods 7/2019)

Small Methods ◽  
2019 ◽  
Vol 3 (7) ◽  
pp. 1970022
Author(s):  
Adrian P. Nievergelt ◽  
Christoph Kammer ◽  
Charlène Brillard ◽  
Eva Kurisinkal ◽  
Maartje M. C. Bastings ◽  
...  
Keyword(s):  
Atomic Force Microscopy ◽  
Self Assembly ◽  
High Speed ◽  
Large Range ◽  
Data Driven ◽  
Force Microscopy ◽  
In Situ Data ◽  
Atomic Force ◽  
Afm Imaging

In-Situ Atomic Force Microscopy (AFM) Imaging: Influence of AFM Probe Geometry on Diffusion to Microscopic Surfaces

Langmuir ◽  
2008 ◽  
Vol 24 (22) ◽  
pp. 12867-12876 ◽  
Author(s):  
David P. Burt ◽  
Neil R. Wilson ◽  
Ulrich Janus ◽  
Julie V. Macpherson ◽  
Patrick R. Unwin
Keyword(s):  
Atomic Force Microscopy ◽  
Force Microscopy ◽  
Atomic Force ◽  
Afm Imaging ◽  
Afm Probe ◽  
Probe Geometry

scholarly journals Reusability of SPE and Sb-modified SPE Sensors for Trace Pb(II) Determination

Sensors ◽  
2018 ◽  
Vol 18 (11) ◽  
pp. 3976 ◽  
Author(s):  
Matjaž Finšgar ◽  
David Majer ◽  
Uroš Maver ◽  
Tina Maver
Keyword(s):  
Electrochemical Impedance ◽  
Standard Addition ◽  
Linear Calibration ◽  
Surface Characterisation ◽  
Force Microscopy ◽  
Atomic Force ◽  
Before And After ◽  
Sensor Degradation ◽  
First Time

In this work, unmodified screen-printed electrode (bare SPE) and Sb-film modified SPE (SbFSPE) sensors were employed for the analysis of trace amounts of Pb(II) in non-deaerated water solutions. The modified electrode was performed in situ in 0.5 mg/L Sb(III) and 0.01 M HCl. The methodology was validated for an accumulation potential of –1.1 V vs. Ag/AgCl and an accumulation time of 60 s. A comparative analysis of bare SPE and SbFSPE showed that the detection and quantification limits decrease for the bare SPE. The method with the bare SPE showed a linear response in the 69.8–368.4 µg/L concentration range, whereas linearity for the SbFSPE was in the 24.0–319.1 µg/L concentration range. This work also reports the reason why the multiple standard addition method instead of a linear calibration curve for Pb(II) analysis should be employed. Furthermore, the analytical method employing SbFSPE was found to be more accurate and precise compared to the use of bare SPE when sensors were employed for the first time, however this performance changed significantly when these sensors were reused in the same manner. Furthermore, electrochemical impedance spectroscopy was used for the first time to analyse the electrochemical response of sensors after being used for multiple successive analyses. Surface characterisation before and after multiple successive uses of bare SPE and SbFSPE sensors, with atomic force microscopy and field emission scanning electron microscopy, showed sensor degradation. The interference effect of Cd(II), Zn(II), As(III), Fe(II), Na(I), K(I), Ca(II), Mg(II), NO3–, Bi(III), Cu(II), Sn(II), and Hg(II) on the Pb(II) stripping signal was also studied. Finally, the application of SbFSPE was tested on a real water sample (from a local river), which showed high precision (RSD = 8.1%, n = 5) and accurate results.

scholarly journals Reusability of SPE and Sb-Mmodified SPE Sensors for Trace Pb(II) Determination

2018 ◽  
Author(s):  
Matjaž Finšgar ◽  
David Majer ◽  
Uroš Maver ◽  
Tina Maver
Keyword(s):  
Electrochemical Impedance ◽  
Standard Addition ◽  
Linear Calibration ◽  
Surface Characterisation ◽  
Force Microscopy ◽  
Atomic Force ◽  
Before And After ◽  
Sensor Degradation ◽  
First Time

In this work, unmodified screen-printed electrode (bare SPE) and Sb-film modified SPE (SbFSPE) sensors were employed for the analysis of trace amounts of Pb(II) in non-deaerated water solutions. The modified electrode was performed in situ in 0.5 mg/L Sb(III) and 0.01 M HCl. The methodology was validated for an accumulation potential of –1.1 V vs. Ag/AgCl and an accumulation time of 60 s. A comparative analysis of bare SPE and SbFSPE showed that the detection and quantification limits decrease for the bare SPE. The method with the bare SPE showed a linear response in the 69.8–368.4 µg/L concentration range, whereas linearity for the SbFSPE was in the 24.0–319.1 µg/L concentration range. This work also reports the reason why the multiple standard addition method instead of a linear calibration curve for Pb(II) analysis should be employed. Furthermore, the analytical method employing SbFSPE was found to be more accurate and precise compared to the use of bare SPE when sensors were employed for the first time, however this performance changed significantly when these sensors were reused in the same manner. Furthermore, electrochemical impedance spectroscopy was used for the first time to analyse the electrochemical response of sensors after being used for multiple successive analyses. Surface characterisation before and after multiple successive uses of bare SPE and SbFSPE sensors, with atomic force microscopy and field emission scanning electron microscopy, showed sensor degradation. The interference effect of Cd(II), Zn(II), As(III), Fe(II), Na(I), K(I), Ca(II), Mg(II), NO3– Bi(III), Cu(II), Sn(II), and Hg(II) on the Pb(II) stripping signal was also studied. Finally, the application of SbFSPE was tested on a real water sample (from a local river), which showed high precision (RSD = 8.1%, n = 5) and accurate results.

scholarly journals Surface Characterization of Absorbing Polymer Films Deposited on Transparent Glasses

e-Polymers ◽  
2008 ◽  
Vol 8 (1) ◽  
Author(s):  
Débora Gonçalves ◽  
Silmar A. Travain ◽  
José A. Giacometti ◽  
Eugene A. Irene
Keyword(s):  
Polymer Films ◽  
Surface Characterization ◽  
Transparent Glass ◽  
Force Microscopy ◽  
Glass Substrates ◽  
Atomic Force ◽  
Vis Spectroscopy ◽  
Before And After

AbstractPANI films were deposited on glass substrates by in-situ polymerization and characterized by UV-VIS spectroscopy and atomic force microscopy. A method is developed to accurately analyze ellipsometric data obtained for transparent glass substrates before and after modification with absorbing polymer films. Surface modification was made with an overlayer such as polyaniline (PANI), which exhibits different optical properties by varying its oxidation state. First, the issue of using transparent substrates for ellipsometry studies was examined and then, spectroscopic ellipsometry was used to characterize absorbing overlayers on transparent glasses. The same methodologies of data analysis can be also applied to other absorbing films on transparent substrates, and deposited by different techniques

scholarly journals Experimental and Theoretical Study of the Covalent Grafting of Triazole Layer onto the Gold Surface

Materials ◽  
2020 ◽  
Vol 13 (13) ◽  
pp. 2927
Author(s):  
Nimet Orqusha ◽  
Sereilakhena Phal ◽  
Avni Berisha ◽  
Solomon Tesfalidet
Keyword(s):  
Photoelectron Spectroscopy ◽  
Density Functional ◽  
Electrochemical Impedance ◽  
Gold Surface ◽  
Covalent Attachment ◽  
Force Microscopy ◽  
Atomic Force ◽  
Covalent Grafting ◽  
Before And After

Finding novel strategies for surface modification is of great interest in electrochemistry and material sciences. In this study, we present a strategy for modification of a gold electrode through covalent attachment of triazole (TA) groups. Triazole groups were electrochemically grafted at the surface of the electrode by a reduction of in situ generated triazolediazonium cations. The resulting grafted surface was characterized before and after the functionalization process by different electrochemical methods (cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS)) confirming the presence of the grafted layer. The grafting of TA on the electrode surface was confirmed using analysis of surface morphology (by atomic force microscopy), the thickness of the grafted layer (by ellipsometry) and its composition (by X-ray photoelectron spectroscopy). Density functional theory (DFT) calculations imply that the grafted triazole offers a stronger platform than the grafted aryl layers.

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