scholarly journals Bulk chemical composition contrast from attractive forces in AFM force spectroscopy

2021 ◽  
Vol 12 ◽  
pp. 58-71
Author(s):  
Dorothee Silbernagl ◽  
Media Ghasem Zadeh Khorasani ◽  
Natalia Cano Murillo ◽  
Anna Maria Elert ◽  
Heinz Sturm
Keyword(s):  
Mechanical Properties ◽  
Chemical Composition ◽  
Chemical Characterization ◽  
Structure Property ◽  
Complete Structure ◽  
Force Microscopy ◽  
Property Correlation ◽  
Force Curves ◽  
Bulk Chemical ◽  
Local Stiffness

A key application of atomic force microscopy (AFM) is the measurement of physical properties at sub-micrometer resolution. Methods such as force–distance curves (FDCs) or dynamic variants (such as intermodulation AFM (ImAFM)) are able to measure mechanical properties (such as the local stiffness, k r) of nanoscopic heterogeneous materials. For a complete structure–property correlation, these mechanical measurements are considered to lack the ability to identify the chemical structure of the materials. In this study, the measured attractive force, F attr, acting between the AFM tip and the sample is shown to be an independent measurement for the local chemical composition and hence a complete structure–property correlation can be obtained. A proof of concept is provided by two model samples comprised of (1) epoxy/polycarbonate and (2) epoxy/boehmite. The preparation of the model samples allowed for the assignment of material phases based on AFM topography. Additional chemical characterization on the nanoscale is performed by an AFM/infrared-spectroscopy hybrid method. Mechanical properties (k r) and attractive forces (F attr) are calculated and a structure–property correlation is obtained by a manual principle component analysis (mPCA) from a k r/F attr diagram. A third sample comprised of (3) epoxy/polycarbonate/boehmite is measured by ImAFM. The measurement of a 2 × 2 µm cross section yields 128 × 128 force curves which are successfully evaluated by a k r/F attr diagram and the nanoscopic heterogeneity of the sample is determined.

scholarly journals Numerical simulation of dual-phase steel based on real and virtual three-dimensional microstructures

2021 ◽  
Author(s):  
Frederik Scherff ◽  
Jessica Gola ◽  
Sebastian Scholl ◽  
Kinshuk Srivastava ◽  
Thorsten Staudt ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Simulation Model ◽  
Dual Phase Steel ◽  
Three Dimensional ◽  
Simultaneous Increase ◽  
Dual Phase ◽  
Structure Property ◽  
Heavy Plate ◽  
Property Correlation ◽  
Process Route

AbstractDual-phase steel shows a strong connection between its microstructure and its mechanical properties. This structure–property correlation is caused by the composition of the microstructure of a soft ferritic matrix with embedded hard martensite areas, leading to a simultaneous increase in strength and ductility. As a result, dual-phase steels are widely used especially for strength-relevant and energy-absorbing sheet metal structures. However, their use as heavy plate steel is also desirable. Therefore, a better understanding of the structure–property correlation is of great interest. Microstructure-based simulation is essential for a realistic simulation of the mechanical properties of dual-phase steel. This paper describes the entire process route of such a simulation, from the extraction of the microstructure by 3D tomography and the determination of the properties of the individual phases by nanoindentation, to the implementation of a simulation model and its validation by experiments. In addition to simulations based on real microstructures, simulations based on virtual microstructures are also of great importance. Thus, a model for the generation of virtual microstructures is presented, allowing for the same statistical properties as real microstructures. With the help of these structures and the aforementioned simulation model, it is then possible to predict the mechanical properties of a dual-phase steel, whose three-dimensional (3D) microstructure is not yet known with high accuracy. This will enable future investigations of new dual-phase steel microstructures within a virtual laboratory even before their production.

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

MRS Advances ◽  
2016 ◽  
Vol 1 (40) ◽  
pp. 2763-2768 ◽  
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.

AFM + Raman Microscopy + SNOM + Tip-Enhanced Raman: Instrumentation and Applications

2010 ◽  
Vol 18 (6) ◽  
pp. 28-32 ◽  
Author(s):  
P. Dorozhkin ◽  
E. Kuznetsov ◽  
A. Schokin ◽  
S. Timofeev ◽  
V. Bykov
Keyword(s):  
Crystal Structure ◽  
Chemical Composition ◽  
Physical Properties ◽  
Force Microscopy ◽  
Research Fields ◽  
Inelastic Light Scattering ◽  
Atomic Force ◽  
Extensive Information ◽  
Local Stiffness

Atomic Force Microscopy (AFM) has developed into a very powerful tool for characterization of surfaces and nanoscale objects. Many physical properties of an object can be studied by AFM with nanometer-scale resolution. Local stiffness, elasticity, conductivity, capacitance, magnetization, surface potential and work function, friction, piezo response—these and many other physical properties can be studied with over 30 AFM modes. What is typically lacking in information provided by AFM studies is the chemical composition of the sample and information about its crystal structure. To obtain this information other characterization techniques are required, such as Raman and fluorescence microscopy. The Raman effect (inelastic light scattering) provides extensive information about sample chemical composition, quality of crystal structure, crystal orientation, presence of impurities and defects, and so on. Information provided by Raman and fluorescence spectroscopy is complementary to the information obtained by AFM. So it is a natural requirement in many research fields to integrate these techniques in one piece of equipment—to provide comprehensive physical, chemical, and structural characterization of the same object. Of course, for routine studies of various samples, it is important to be able to obtain AFM and Raman/fluorescence images of exactly the same sample area, preferably with the same sample scan.

Pulping-tailored fiber properties from a novel Brazilian Eucalyptus hybrid

Holzforschung ◽  
2014 ◽  
Vol 68 (3) ◽  
pp. 273-282 ◽  
Author(s):  
Marcelo Coelho dos Santos Muguet ◽  
Fernando José Borges Gomes ◽  
Kyösti Ruuttunen ◽  
Leena-Sisko Johansson ◽  
Anna-Stiina Jääskeläinen ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Chemical Composition ◽  
Photoelectron Spectroscopy ◽  
Lignin Content ◽  
Eucalyptus Grandis ◽  
Physical And Mechanical Properties ◽  
Pulp Fibers ◽  
Fiber Properties ◽  
Thermomechanical Pulping ◽  
Bulk Chemical

Abstract The chemical composition and morphology of pulp fibers have a significant impact on the properties of fiber products. Pulp samples from a novel unique Eucalyptus triple hybrid [Eucalyptus grandis × (Eucalyptus urophylla × Eucalyptus globulus)] were obtained by various pulping processes – kraft, soda-anthraquinone (NaOH-AQ), and thermomechanical pulping (TMP). The chemical composition of the fiber surfaces was evaluated by X-ray photoelectron spectroscopy (XPS). The surface lignin content of NaOH-AQ pulp fibers was lower than that of the kraft counterpart. However, kraft pulp handsheets showed better physical and mechanical properties. XPS data strongly suggests that together with the pulp bulk chemical composition the xylan is more abundant on the surface of kraft fibers, which is reflected on their better mechanical properties. Moreover, the relatively low surface lignin content in TMP pulp compared to wood suggests that defibration takes place in the secondary wall, where lignin is less concentrated.

Structure-Property Correlation of Composites Impregnated with Aspartimide Oligomer

2012 ◽  
Vol 602-604 ◽  
pp. 28-32
Author(s):  
Peng Chang Ma ◽  
Hong Bo Liu
Keyword(s):  
Mechanical Properties ◽  
Chain Length ◽  
Crosslink Density ◽  
Loss Modulus ◽  
Fiber Composites ◽  
Structure Property ◽  
Glass Fiber Composites ◽  
Polymer Resin ◽  
Property Correlation ◽  
Properties Of Composites

Carbon fiber and glass fiber composites impregnated with aspartimide oligomer were fabricated and their structure-property correlation was studied. Experimental results reveal that with increasing chain length of aspartimide oligomer, mechanical properties of composites increase, but thermal properties decrease. With decreasing chain length, storage modulus and loss tan delta peak temperature of composite increase as a consequence of increased rigidity of matrix polymer resin resulted from crosslink density increase, concurrently, loss modulus and tan delta value of composites undergo a decrease.

Relating Polymer Indentation Behavior to Elastic Modulus Using Atomic Force Microscopy

1996 ◽  
Vol 440 ◽  
Author(s):  
M. R. Vanlandingham ◽  
S. H. Mcknight ◽  
G. R. Palmese ◽  
R. F. Eduljee ◽  
J. W. Gillespie ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Elastic Modulus ◽  
Force Microscopy ◽  
Atomic Force ◽  
Different Types ◽  
Force Curves ◽  
Measured Sample ◽  
Cantilever Probes ◽  
Spring Constants ◽  
Cantilever Probe

AbstractThe atomic force microscope (AFM) has become a popular tool for characterizing surfaces of many different types of materials. In this paper, an AFM is used to probe the mechanical properties of polymer samples through examination of force curves produced during tip-sample contact and indentation. Three types of cantilever probes with spring constants estimated to be 1–5 N/m, 20–100 N/m, and 400–500 N/m respectively, were used to study different polymer samples with known modulus values ranging from 20 MPa to 3 GPa. A technique is developed that relates the measured sample response to elastic modulus, and illuminates the importance of the relative stiffnesses of the cantilever probe and the sample to the material response.

Structure - Property and Structure - Function Relations of Leafhopper (Kahaono montana) Silk

2006 ◽  
Vol 59 (8) ◽  
pp. 579 ◽  
Author(s):  
Jung C. Chang ◽  
Geoff M. Gurr ◽  
Murray J. Fletcher ◽  
Robert G. Gilbert
Keyword(s):  
Random Coil ◽  
Structure Property ◽  
Force Microscopy ◽  
Structural Support ◽  
Insect Order ◽  
Atomic Force ◽  
Hydrophobic Barrier ◽  
Force Curves ◽  
Α Helix ◽  
First Time

Kahaono montana Evans (Insecta: Hemiptera: Cicadellidae), an endemic Australian leafhopper, is unique among the insect order Hemiptera in producing a silk. In this study, the secondary structure of the protein comprising leafhopper silk, and the surface stretching mechanical properties of this biopolymer, were investigated using Fourier-transform infrared microscopy and atomic force microscopy, respectively. The curve-fitted amide I and amide III bands revealed a composition of 13.1% α-helix, 23.8% β-sheet, 25.5% random coil, and 37.6% aggregated side chains. The molecular stretching behaviour of raw and cleaned silk fibres differed markedly. Analysis of the AFM force curves showed an adhesive property of the raw silk, while the pure fibre showed only the presence of protein. These findings suggest that the silk fibres act as a structural support for other leafhopper secretions and together form a hydrophobic barrier that may protect the insects from rain and natural enemies. This is the first time such a use of silk has been found in a biological system.

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