Nanoscale Mechanical Properties and Indentation Recovery of PI@GO Composites Measured Using AFM

Polyimide@graphene oxide (PI@GO) composites were prepared by way of a simple solution blending method. The nanoscale hardness and Young’s modulus of the composites were measured using nanoindentation based on atomic force microscopy (AFM). A nanoscale hardness of ~0.65 GPa and an elastic modulus of ~6.5 GPa were reached with a load of ~55 μN. The indentation recovery on the surface of PI@GO was evaluated. The results show that relatively low GO content can remarkably improve the nanoscale mechanical properties of PI.

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Alteration of nanomechanical properties of pancreatic cancer cells through anticancer drug treatment revealed by atomic force microscopy

Beilstein Journal of Nanotechnology ◽

10.3762/bjnano.12.101 ◽

2021 ◽

Vol 12 ◽

pp. 1372-1379

Author(s):

Xiaoteng Liang ◽

Shuai Liu ◽

Xiuchao Wang ◽

Dan Xia ◽

Qiang Li

Keyword(s):

Mechanical Properties ◽

Pancreatic Cancer ◽

Atomic Force Microscopy ◽

Cancer Cells ◽

Young’S Modulus ◽

Young's Modulus ◽

Force Microscopy ◽

Pancreatic Cancer Cells ◽

Atomic Force ◽

Aggressive Cancer

The mechanical properties of cells are key to the regulation of cell activity, and hence to the health level of organisms. Here, the morphology and mechanical properties of normal pancreatic cells (HDPE6-C7) and pancreatic cancer cells (AsPC-1, MIA PaCa-2, BxPC-3) were studied by atomic force microscopy. In addition, the mechanical properties of MIA PaCa-2 after treatment with different concentrations of doxorubicin hydrochloride (DOX) were also investigated. The results show the Young's modulus of normal cells is greater than that of three kinds of cancer cells. The Young's modulus of more aggressive cancer cell AsPC-1 is smaller than that of less aggressive cancer cell BxPC-3. In addition, the Young's modulus of MIA PaCa-2 rises with the increasing of DOX concentration. This study may provide a new strategy of detecting cancer, and evaluate the possible interaction of drugs on cells.

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Atomic force microscopy-based nanomechanical characterization of kenaf fiber

Journal of Composite Materials ◽

10.1177/0021998319892073 ◽

2019 ◽

Vol 54 (15) ◽

pp. 2065-2071 ◽

Cited By ~ 1

Author(s):

M Subbir Parvej ◽

Xinnan Wang ◽

Joseph Fehrenbach ◽

Chad A Ulven

Keyword(s):

Mechanical Properties ◽

Atomic Force Microscopy ◽

Elastic Modulus ◽

Adhesion Force ◽

Fiber Surface ◽

Gauge Length ◽

Hibiscus Cannabinus ◽

Kenaf Fiber ◽

Force Microscopy ◽

Atomic Force

Kenaf ( Hibiscus cannabinus L.) fiber is being extensively used as a reinforcement material in composites due to its excellent mechanical properties. To use this fiber more efficiently, it is necessary to understand its mechanical properties at micro/nano meter scale. Despite the evidence of some past studies to determine the elastic modulus of kenaf fiber, most of them were performed on fiber bundles. Bundle-based method to find the elastic moduli has some obvious issues of foreign materials being present, incorrect gauge length, and sample diameter due to void spaces. These issues pose as obvious hurdles to determine the elastic modulus accurately. In this study, individual kenaf micro fiber was used to find elastic modulus in the radial direction. The radial elastic modulus of the fiber was characterized by atomic force microscopy-based nanoindentation. To determine the radial elastic modulus from the force versus sample deformation data, the extended Johnson–Kendall–Roberts model was used which considered adhesion force from the fiber surface. The radial elastic modulus of the kenaf fiber was found to be 2.3 GPa.

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Mechanical Characterization of Reduced Graphene Oxide Using AFM

Advances in Condensed Matter Physics ◽

10.1155/2019/8713965 ◽

2019 ◽

Vol 2019 ◽

pp. 1-13 ◽

Cited By ~ 5

Author(s):

Alem Teklu ◽

Canyon Barry ◽

Matthew Palumbo ◽

Collin Weiwadel ◽

Narayanan Kuthirummal ◽

...

Keyword(s):

Atomic Force Microscopy ◽

Graphene Oxide ◽

Young’S Modulus ◽

Reduced Graphene Oxide ◽

Young's Modulus ◽

Force Microscopy ◽

Atomic Force ◽

Reduction Cycle ◽

Reduced Graphene ◽

Oxide Sample

Nanoindentation coupled with Atomic Force Microscopy was used to study stiffness, hardness, and the reduced Young’s modulus of reduced graphene oxide. Oxygen reduction on the graphene oxide sample was performed via LightScribe DVD burner reduction, a cost-effective approach with potential for large scale graphene production. The reduction of oxygen in the graphene oxide sample was estimated to about 10 percent using FTIR spectroscopic analysis. Images of the various samples were captured after each reduction cycle using Atomic Force Microscopy. Elastic and spectroscopic analyses were performed on the samples after each oxygen reduction cycle in the LightScribe, thus allowing for a comparison of stiffness, hardness, and the reduced Young’s modulus based on the number of reduction cycles. The highest values obtained were after the fifth and final reduction cycle, yielding a stiffness of 22.4 N/m, a hardness of 0.55 GPa, and a reduced Young’s modulus of 1.62 GPa as compared to a stiffness of 22.8 N/m, a hardness of 0.58 GPa, and a reduced Young’s modulus of 1.84 GPa for a commercially purchased graphene film made by CVD. This data was then compared to the expected values of pristine single layer graphene. Furthermore, two RC circuits were built, one using a parallel plate capacitors made of light scribed graphene on a kapton substrate (LSGC) and a second one using a CVD deposited graphene on aluminum (CVDGC). Their RC time constants and surface charge densities were compared.

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Elucidating nanoscale mechanical properties of diabetic human adipose tissue using atomic force microscopy

Scientific Reports ◽

10.1038/s41598-020-77498-w ◽

2020 ◽

Vol 10 (1) ◽

Author(s):

J. K. Wenderott ◽

Carmen G. Flesher ◽

Nicki A. Baker ◽

Christopher K. Neeley ◽

Oliver A. Varban ◽

...

Keyword(s):

Mechanical Properties ◽

Metabolic Disease ◽

Atomic Force Microscopy ◽

Adipose Tissue ◽

Elastic Modulus ◽

Tissue Mechanics ◽

Health Concern ◽

Force Microscopy ◽

Atomic Force ◽

The Impact

AbstractObesity-related type 2 diabetes (DM) is a major public health concern. Adipose tissue metabolic dysfunction, including fibrosis, plays a central role in DM pathogenesis. Obesity is associated with changes in adipose tissue extracellular matrix (ECM), but the impact of these changes on adipose tissue mechanics and their role in metabolic disease is poorly defined. This study utilized atomic force microscopy (AFM) to quantify difference in elasticity between human DM and non-diabetic (NDM) visceral adipose tissue. The mean elastic modulus of DM adipose tissue was twice that of NDM adipose tissue (11.50 kPa vs. 4.48 kPa) to a 95% confidence level, with significant variability in elasticity of DM compared to NDM adipose tissue. Histologic and chemical measures of fibrosis revealed increased hydroxyproline content in DM adipose tissue, but no difference in Sirius Red staining between DM and NDM tissues. These findings support the hypothesis that fibrosis, evidenced by increased elastic modulus, is enhanced in DM adipose tissue, and suggest that measures of tissue mechanics may better resolve disease-specific differences in adipose tissue fibrosis compared with histologic measures. These data demonstrate the power of AFM nanoindentation to probe tissue mechanics, and delineate the impact of metabolic disease on the mechanical properties of adipose tissue.

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Mapping of Nanoscale Mechanical Properties of Polymers in Quasi-static and Oscillatory Atomic Force Microscopy Modes

MRS Advances ◽

10.1557/adv.2016.539 ◽

2016 ◽

Vol 1 (40) ◽

pp. 2763-2768 ◽

Cited By ~ 3

Author(s):

Sergei Magonov ◽

Marko Surtchev ◽

John Alexander ◽

Ivan Malovichko ◽

Sergey Belikov

Keyword(s):

Mechanical Properties ◽

Atomic Force Microscopy ◽

Elastic Modulus ◽

Polymer Materials ◽

Work Of Adhesion ◽

Force Microscopy ◽

Atomic Force ◽

Time Dependencies ◽

Force Curves ◽

20 Nm

ABSTRACTRecent advances in studies of local mechanical properties of polymers with different atomic force microscopy techniques (contact, Hybrid and amplitude modulation modes) are described in interplay between experiment and theory. Analysis of force curves and time dependencies of probe response to sample compliance, which were recorded on a number of polymer materials at various temperatures, leads to quantitative mapping of specific mechanical properties (elastic modulus, work of adhesion, etc). High spatial resolution of elastic modulus mapping (10-20 nm) is illustrated in measurements of lamellar structures of several polymers. Challenges of examination of viscoelastic properties are pointed out and a possible solution is presented.

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Ultrastructural and nanomechanical changes of the cornea following enzymatic degradation

Modeling and Artificial Intelligence in Ophthalmology ◽

10.35119/maio.v2i2.67 ◽

2018 ◽

Vol 2 (2) ◽

pp. 24-29

Author(s):

Ahmed Kazaili ◽

Riaz Akhtar

Keyword(s):

Mechanical Properties ◽

Atomic Force Microscopy ◽

Elastic Modulus ◽

Enzymatic Degradation ◽

Enzymatic Treatment ◽

Force Microscopy ◽

Collagen Organization ◽

Atomic Force ◽

Ocular Disorders ◽

Porcine Cornea

Understanding of the ultrastructure and nanomechanical behavior of the cornea is important for a number of ocular disorders. In this study, atomic force microscopy (AFM) was used to determine nanoscale changes in the porcine cornea following enzymatic degradation. Diff erent concentrations of amylase were used to degrade the cornea. A reduction in elastic modulus at the nanoscale, along with disrupted collagen morphology, was observed following enzymatic treatment. This study highlights the interplay between mechanical properties and collagen organization in the healthy cornea.

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In Situ Measurement of Elastic and Frictional Properties Using Atomic Force Microscopy

Microscopy and Microanalysis ◽

10.1017/s143192762101285x ◽

2021 ◽

pp. 1-10

Author(s):

Ngoc-Phat Huynh ◽

Tuan-Em Le ◽

Koo-Hyun Chung

Keyword(s):

Mechanical Properties ◽

Atomic Force Microscopy ◽

Elastic Modulus ◽

Force Microscopy ◽

Frictional Properties ◽

Atomic Force ◽

Proposed Model ◽

Significant Difference ◽

Modulus Measurement

Atomic force microscopy (AFM) can determine mechanical properties, associated with surface topography and structure, of a material at the nanoscale. Force–indentation curves that depict the deformation of a target specimen as a function of an applied force are widely used to determine the elastic modulus of a material based on a contact model. However, a hysteresis may arise due to friction between the AFM tip and a specimen. Consequently, the normal force detected using a photodetector during extension and retraction could be underestimated and overestimated, respectively, and the extension/retraction data could result in a significant difference in the elastic modulus measurement result. In this study, elastic modulus and friction coefficient values were determined based on an in situ theoretical model that compensated for the effect of friction on force–indentation data. It validated the proposed model using three different polymer specimens and colloidal-tipped probes for the force–indentation curve and friction loop measurements. This research could contribute to the accurate measurement of mechanical properties using AFM by enhancing the interpretation of force–indentation curves with friction-induced hysteresis. Furthermore, the proposed approach may be useful for analyzing in situ relationships between mechanical and frictional properties from a fundamental tribological perspective.

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Steel Pile-Up Characterization by Atomic Force Microscopy

Materials Science Forum ◽

10.4028/www.scientific.net/msf.891.78 ◽

2017 ◽

Vol 891 ◽

pp. 78-82 ◽

Cited By ~ 1

Author(s):

Peter Burik ◽

Pavol Zubko ◽

Ladislav Pešek ◽

Lukáš Voleský

Keyword(s):

Mechanical Properties ◽

Atomic Force Microscopy ◽

Young’S Modulus ◽

Mechanical Characteristics ◽

The Real ◽

Force Microscopy ◽

Contact Depth ◽

Steel Sheets ◽

Atomic Force ◽

Pile Up

The Oliver–Pharr method has extensively been adopted for measuring hardness and Young’s modulus by indentation techniques. However, the method assumes that the contact periphery sinks in, which limits the applicability to the materials pile-up [1]. In this work, we characterize the pile-up (shape and height) in steel sheets with different mechanical properties and propose an improved methodology to calculate the real mechanical characteristics of steel sheets with significant pile-up. Pile-up correction of mechanical characteristics is based on ratio of pile-up height and contact depth. Pile-up height was measured by atomic force microscopy (AFM).

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Nanoscale spatial mapping of mechanical properties through dynamic atomic force microscopy

Beilstein Journal of Nanotechnology ◽

10.3762/bjnano.10.132 ◽

2019 ◽

Vol 10 ◽

pp. 1332-1347 ◽

Cited By ~ 1

Author(s):

Zahra Abooalizadeh ◽

Leszek Josef Sudak ◽

Philip Egberts

Keyword(s):

Experimental Data ◽

Mechanical Properties ◽

Atomic Force Microscopy ◽

Elastic Modulus ◽

Pyrolytic Graphite ◽

Spatial Mapping ◽

Atomic Steps ◽

Force Microscopy ◽

Atomic Force ◽

Quantitative Results

Dynamic atomic force microscopy (AFM) was employed to spatially map the elastic modulus of highly oriented pyrolytic graphite (HOPG), specifically by using force modulation microscopy (FMM) and contact resonance (CR) AFM. In both of these techniques, a variation in the amplitude signal was observed when scanning over an uncovered step edge of HOPG. In comparison, no variation in the amplitude signal was observed when scanning over a covered step on the same surface. These observations qualitatively indicate that there is a variation in the elastic modulus over uncovered steps and no variation over covered ones. The quantitative results of the elastic modulus required the use of FMM, while the CR mode better highlighted areas of reduced elastic modulus (although it was difficult to convert the data into a quantifiable modulus). In the FMM measurements, single atomic steps of graphene with uncovered step edges showed a decrease in the elastic modulus of approximately 0.5%, which is compared with no change in the elastic modulus for covered steps. The analysis of the experimental data taken under varying normal loads and with several different tips showed that the elastic modulus determination was unaffected by these parameters.

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