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Full-Text Articles in Biomedical Engineering and Bioengineering
Phase Imaging: Deep Or Superficial?, Nancy Burnham, O Behrend, L Odoni, J Loubet
Phase Imaging: Deep Or Superficial?, Nancy Burnham, O Behrend, L Odoni, J Loubet
Nancy A. Burnham
Phase images acquired while intermittently contacting a sample surface with the tip of an atomic force microscope cantilever are not easy to relate to material properties. We have simulated dynamic force curves and compared simulated with experimental results. For some cantilever–sample combinations, the interaction remains a surface effect, whereas for others, the tip penetrates the sample significantly. Height artifacts in the “topography” images, and the role of the sample stiffness, work of adhesion, damping, and topography in the cantilever response manifest themselves to different extents depending on the indentation depth.
Local Mechanical Spectroscopy With Nanometer-Scale Lateral Resolution, Nancy Burnham, F Oulevey, G Gremaud, A Semoroz, Aj Kulik, E Dupas, D Gourdon
Local Mechanical Spectroscopy With Nanometer-Scale Lateral Resolution, Nancy Burnham, F Oulevey, G Gremaud, A Semoroz, Aj Kulik, E Dupas, D Gourdon
Nancy A. Burnham
A new technique has been developed to probe the viscoelastic and anelastic properties of submicron phases of inhomogeneous materials. The measurement gives information related to the internal friction and to the variations of the dynamic modulus of nanometer-sized volumes. It is then the nanoscale equivalent to mechanical spectroscopy, a well-known macroscopic technique for materials studies, also sometimes called dynamic mechanical (thermal) analysis. The technique is based on a scanning force microscope, using the principle of scanning local-acceleration microscopy (SLAM), and allows the sample temperature to be changed. It is called variable-temperature SLAM, abbreviated T-SLAM. According to a recent proposition to …
Materials’ Properties Measurements: Choosing The Optimal Scanning Probe Microscope Configuration, Nancy Burnham, G Gremaud, A Kulik, P Gallo, F Oulevey
Materials’ Properties Measurements: Choosing The Optimal Scanning Probe Microscope Configuration, Nancy Burnham, G Gremaud, A Kulik, P Gallo, F Oulevey
Nancy A. Burnham
Rheological models are used to represent different scanning probe microscope configurations. The solutions for their static and dynamic behavior are found and used to analyze which scanning probe microscope configuration is best for a given application. We find that modulating the sample at high frequencies results in the best microscope behavior for measuring the stiffness of rigid materials, and that by modulating the tip at low frequencies and detecting the motion of the tip itself (not its position relative to the tip holder) should be best for studying compliant materials in liquids.
Interpretation Issues In Force Microscopy, Nancy Burnham, Richard Colton, Hubert Pollock
Interpretation Issues In Force Microscopy, Nancy Burnham, Richard Colton, Hubert Pollock
Nancy A. Burnham
In this paper, we will discuss force microscopy (FM) and its potential for determining mechanical properties of thin films. We will introduce the basic principles of FM, and demonstrate how FM can be used to determine materials properties as well as image surface topography, both with nanonewton or sub‐nanonewton force resolution and sub‐nanometer position resolution. As FM is still a new field, not all of the questions concerning interpretation have been fully answered. We will elucidate four current issues that must be resolved before the full potential of FM can be realized. They are: (1) the role of water vapor …
Measuring The Nanomechanical Properties And Surface Forces Of Materials Using An Atomic Force Microscope, Nancy Burnham, Richard Colton
Measuring The Nanomechanical Properties And Surface Forces Of Materials Using An Atomic Force Microscope, Nancy Burnham, Richard Colton
Nancy A. Burnham
An atomic force microscope(AFM) has been configured so that it measures the force between a tip mounted on a cantilever beam and a sample surface as a function of the tip–surface separation. This allows the AFM to study both the nanomechanical properties of the sample and the forces associated with the tip–surface interaction. More specifically, the AFM can measure the elastic and plastic behavior and hardness via nanoindentation,van der Waals forces, and the adhesion of thin‐film and bulk materials with unprecedented force and spatial resolution. The force resolution is currently 1 nanonewton, and the depth resolution is 0.02 nm. Additionally, …