Substrate effects on nanoindentation mechanical property measurement of soft films on hard substrates

1999 ◽  
Vol 14 (1) ◽  
pp. 292-301 ◽  
Author(s):  
T. Y. Tsui ◽  
G. M. Pharr
Keyword(s):  
Elastic Modulus ◽  
Measurement Techniques ◽  
Substrate Effects ◽  
Aluminum Films ◽  
Force Microscopy ◽  
Atomic Force ◽  
Film Hardness ◽  
Nanoindentation Measurement ◽  
Property Measurement ◽  
Sputter Deposited

Substrate effects on the measurement of thin film mechanical properties by nanoindentation methods have been studied experimentally using a model soft film on hard substrate system: aluminum on glass. The hardness and elastic modulus of aluminum films with thicknesses of 240, 650, and 1700 nm sputter-deposited on glass were systematically characterized as a function of indenter penetration depth using standard nanoindentation methods. Scanning electron and atomic force microscopy of the hardness impressions revealed that indentation pileup in the aluminum is significantly enhanced by the substrate. The substrate also affects the form of the unloading curve in a manner that has important implications for nanoindentation data analysis procedures. Because of these effects, nanoindentation measurement techniques overestimate the film hardness and elastic modulus by as much as 100% and 50%, respectively, depending on the indentation depth. The largest errors occur at depths approximately equal to the film thickness.

Nanomechanical Properties of SiC Films Grown From C60 Precursors Using Atomic Force Microscopy

1997 ◽  
Vol 119 (1) ◽  
pp. 26-30 ◽  
Author(s):  
K. Morse ◽  
T. P. Weihs ◽  
A. V. Hamza ◽  
M. Balooch ◽  
Z. Jiang ◽  
...  
Keyword(s):  
Atomic Force Microscopy ◽  
Elastic Modulus ◽  
Silicon Nitride ◽  
Friction Coefficient ◽  
Force Microscopy ◽  
Nanomechanical Properties ◽  
Atomic Force ◽  
Film Hardness ◽  
Sic Film ◽  
Sic Films

The mechanical properties of SiC films grown via C60 precursors were determined using atomic force microscopy (AFM). Conventional silicon nitride and diamond-tipped steel AFM cantilevers were employed to determine the film hardness, friction coefficient, and elastic modulus. The hardness is found to be 26 GPa by nanoindentation of the film with a Berkovich diamond tip. The friction coefficient for the silicon nitride tip on the SiC film is about one half to one third that for silicon nitride sliding on a silicon substrate. By combining nanoindentation and AFM measurements an elastic modulus of ~300 GPa is estimated for these SiC films.

scholarly journals A Universal Model for the Log-Normal Distribution of Elasticity in Polymeric Gels and Its Relevance to Mechanical Signature of Biological Tissues

Biology ◽  
2021 ◽  
Vol 10 (1) ◽  
pp. 64
Author(s):  
Arnaud Millet
Keyword(s):  
Elastic Modulus ◽  
Normal Distribution ◽  
Biological Tissues ◽  
Force Microscopy ◽  
Polymeric Gels ◽  
Atomic Force ◽  
Clear Explanation ◽  
Log Normal ◽  
Log Normal Distribution

The mechanosensitivity of cells has recently been identified as a process that could greatly influence a cell’s fate. To understand the interaction between cells and their surrounding extracellular matrix, the characterization of the mechanical properties of natural polymeric gels is needed. Atomic force microscopy (AFM) is one of the leading tools used to characterize mechanically biological tissues. It appears that the elasticity (elastic modulus) values obtained by AFM presents a log-normal distribution. Despite its ubiquity, the log-normal distribution concerning the elastic modulus of biological tissues does not have a clear explanation. In this paper, we propose a physical mechanism based on the weak universality of critical exponents in the percolation process leading to gelation. Following this, we discuss the relevance of this model for mechanical signatures of biological tissues.

Preparation and Research on the Lateral Elastic Modulus of the MnO2 Nanowires

2013 ◽  
Vol 662 ◽  
pp. 84-87
Author(s):  
Yong Jiang ◽  
Jian Cheng Deng ◽  
Yan Huai Ding ◽  
Jiu Ren Yin ◽  
Ping Zhang
Keyword(s):  
Elastic Modulus ◽  
Crystal Form ◽  
Bending Test ◽  
X Ray Diffraction ◽  
Nanowire Diameter ◽  
X Ray ◽  
Three Point Bending ◽  
Force Microscopy ◽  
Atomic Force ◽  
Mno2 Nanowires

MnO2 nanowires with large aspect ratio were successfully synthesized via a hydrothermal method. In this method, Mn(NO3)2 was as a source of manganese and NH4NO3 as an oxidant. The structure and morphology of the MnO2 nanowires were characterized by X ray diffraction (XRD) and scanning electron microscope (SEM). Their lateral elastic modulus was characterized via a nanoscale three-point bending test by atomic force microscopy (AFM) equipped with picoforce. The results indicate that the crystal form of MnO2 was β-MnO2. The elastic modulus of the nanowires decreased with the increase in nanowire diameter. This elastic modulus was in the range of 33.36-77.84GPa as the diameter ranged from 240 to 185nm.

Elastic Modulus of Single Cellulose Microfibrils from Tunicate Measured by Atomic Force Microscopy

2009 ◽  
Vol 10 (9) ◽  
pp. 2571-2576 ◽  
Author(s):  
Shinichiro Iwamoto ◽  
Weihua Kai ◽  
Akira Isogai ◽  
Tadahisa Iwata
Keyword(s):  
Atomic Force Microscopy ◽  
Elastic Modulus ◽  
Cellulose Microfibrils ◽  
Force Microscopy ◽  
Atomic Force

Quantitative mechanical analysis of indentations on layered, soft elastic materials

Soft Matter ◽  
2019 ◽  
Vol 15 (8) ◽  
pp. 1776-1784 ◽  
Author(s):  
Bryant L. Doss ◽  
Kiarash Rahmani Eliato ◽  
Keng-hui Lin ◽  
Robert Ros
Keyword(s):  
Atomic Force Microscopy ◽  
Elastic Modulus ◽  
Cell Mechanics ◽  
Biological Samples ◽  
Mechanical Analysis ◽  
Elastic Materials ◽  
Mechanical Heterogeneity ◽  
Popular Method ◽  
Force Microscopy ◽  
Atomic Force

Atomic force microscopy (AFM) is becoming an increasingly popular method for studying cell mechanics, however the existing analysis tools for determining the elastic modulus from indentation experiments are unable to quantitatively account for mechanical heterogeneity commonly found in biological samples.

scholarly journals A Novel Toolkit for Characterizing the Mechanical and Electrical Properties of Engineered Neural Tissues

Biosensors ◽  
2019 ◽  
Vol 9 (2) ◽  
pp. 51 ◽  
Author(s):  
Meghan Robinson ◽  
Karolina Valente ◽  
Stephanie Willerth
Keyword(s):  
Elastic Modulus ◽  
Electrical Properties ◽  
Elastic Moduli ◽  
Direct Method ◽  
Hydrogel Scaffolds ◽  
Force Microscopy ◽  
Mechanical And Electrical Properties ◽  
Atomic Force ◽  
Neural Tissues ◽  
Electrical Signaling

We have designed and validated a set of robust and non-toxic protocols for directly evaluating the properties of engineered neural tissue. These protocols characterize the mechanical properties of engineered neural tissues and measure their electrophysical activity. The protocols obtain elastic moduli of very soft fibrin hydrogel scaffolds and voltage readings from motor neuron cultures. Neurons require soft substrates to differentiate and mature, however measuring the elastic moduli of soft substrates remains difficult to accurately measure using standard protocols such as atomic force microscopy or shear rheology. Here we validate a direct method for acquiring elastic modulus of fibrin using a modified Hertz model for thin films. In this method, spherical indenters are positioned on top of the fibrin samples, generating an indentation depth that is then correlated with elastic modulus. Neurons function by transmitting electrical signals to one another and being able to assess the development of electrical signaling serves is an important verification step when engineering neural tissues. We then validated a protocol wherein the electrical activity of motor neural cultures is measured directly by a voltage sensitive dye and a microplate reader without causing damage to the cells. These protocols provide a non-destructive method for characterizing the mechanical and electrical properties of living spinal cord tissues using novel biosensing methods.

scholarly journals An investigation of surface properties, local elastic modulus and interaction with simulated pulmonary surfactant of surface modified inhalable voriconazole dry powders using atomic force microscopy

RSC Advances ◽  
2016 ◽  
Vol 6 (31) ◽  
pp. 25789-25798 ◽  
Author(s):  
Sumit Arora ◽  
Michael Kappl ◽  
Mehra Haghi ◽  
Paul M. Young ◽  
Daniela Traini ◽  
...  
Keyword(s):  
Atomic Force Microscopy ◽  
Elastic Modulus ◽  
Surface Properties ◽  
Pulmonary Surfactant ◽  
Dry Powders ◽  
Force Microscopy ◽  
Atomic Force ◽  
Surface Modified ◽  
Spray Dried

l-Leucine modified voriconazole spray dried micropartcles.

scholarly journals Mechanical Characterization of a Dynamic and Tunable Methacrylated Hyaluronic Acid Hydrogel

2016 ◽  
Vol 138 (2) ◽  
Author(s):  
Matthew G. Ondeck ◽  
Adam J. Engler
Keyword(s):  
Hyaluronic Acid ◽  
Elastic Modulus ◽  
Monomer Concentration ◽  
Degree Of Polymerization ◽  
Force Microscopy ◽  
3T3 Fibroblasts ◽  
Atomic Force ◽  
Spread Area ◽  
Nih 3T3

Hyaluronic acid (HA) is a commonly used natural polymer for cell scaffolding. Modification by methacrylate allows it to be polymerized by free radicals via addition of an initiator, e.g., light-sensitive Irgacure, to form a methacrylated hyaluronic acid (MeHA) hydrogel. Light-activated crosslinking can be used to control the degree of polymerization, and sequential polymerization steps allow cells plated onto or in the hydrogel to initially feel a soft and then a stiff matrix. Here, the elastic modulus of MeHA hydrogels was systematically analyzed by atomic force microscopy (AFM) for a number of variables including duration of UV exposure, monomer concentration, and methacrylate functionalization. To determine how cells would respond to a specific two-step polymerization, NIH 3T3 fibroblasts were cultured on the stiffening MeHA hydrogels and found to reorganize their cytoskeleton and spread area upon hydrogel stiffening, consistent with cells originally cultured on substrates of the final elastic modulus.

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