PolyInsight : Atomic Force Microscopy Services for Nanostructured Materials

Atomic-Force Microscopy (AFM)

What is AFM (Atomic Force Microscopy)?

Atomic Force Microscopy is one of thre three most common scanning probe techniques.

Atomic Force Microscopy measures the interaction force between the tip of the microscopy and the surface being measured. As the tip is dragged along the surface or vibrates as a result of other motion different interaction forces will be observed that will reveal characteristics of the sample material.

The atomic force microscope is one of about two dozen types of scanned-proximity probe microscopes. All of these microscopes work by measuring a local property - such as height, optical absorption, or magnetism - with a probe or "tip" placed very close to the sample. The small probe-sample separation (on the order of the instrument's resolution) makes it possible to take measurements over a small area. To acquire an image the microscope raster-scans the probe over the sample while measuring the local property in question. The resulting image resembles an image on a television screen in that both consist of many rows or lines of information placed one above the other.

Unlike traditional microscopes, scanned-probe systems do not use lenses, so the size of the probe rather than diffraction effects generally limit their resolution.

How does SPM work?

Scanning probe microscopy is used for imaging and measuring surfaces on a very fine level, from surfaces over 100 micrometers wide and up to 4 micrometers deep, down to the scale of individual molecules and groups of atoms. 

SPM technologies scan an extremely sharp tip (3 to 50 nm radius of curvature) across a surface. The tip is mounted on a movable, flexing cantilever, allowing the tip to follow the surface profile closely to increase accuracy.

When the tip moves in proximity to the surface of the examined object, forces between the tip and the surface influence the movement of the cantilever.  These movements are detected by sensors on the unit.

Why is SPM (Scanning Probe Microscopy) needed?

Performance of materials can be influenced by their minute structural features.  Materials with features that can be viewed with an optical microscope have microstructures.  Materials with even smaller features have nano structures.  Specialized instruments and expertise are needed to observe and analyze these tiny structures.

For information on how PolyInsight can help maximize the performance of your material, call us at 330-777-0025 or email info@polyinsight.com

Internal structure of wheat starch. The distribution of crystalline amylopectin and amorphous amylose can be observed using AFM due to their difference in mechanical properties.

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