New opportunities for structure investigation at the DIL

Since August 2010, the DIL is able to examine structures even more precisely. Apart from established processes such as optical microscopy, scanning electron microscopy and confocal laser scanning microscopy, there is now also a scanning force microscope available for research and individual services...

Since August 2010, the DIL is able to examine structures even more precisely. Apart from established processes such as optical microscopy, scanning electron microscopy and confocal laser scanning microscopy, there is now also a scanning force microscope available for research and individual services.

The scanning force microscope, also called atomic force microscope (AFM), is a special type of scanning probe microscope. It is an important tool for the analysis of surfaces. It “feels” the structure of the surfaces mechanically and also determines atomic interactions. This microscope is the instrument of choice for three-dimensional measurements and imaging in the nanoscale range.

The AFM measures the forces between the sample and a scanning tip. The tip is located at the end of a so-called cantilever, a spring hanger with a defined spring constant that is guided along the surface of the sample.

Depending on the respective application, different imaging methods and measuring modes can be employed. In addition to the characterization of the topography, the scanning force microscopy can also be used for the determination of lateral forces (areas of different surface friction) and the recording of force-distance-curves. Furthermore, this method can be used for the determination of surface potentials, polarities and magnetic properties as well as for force spectroscopic measurements, e.g. for the description of rheological properties of the boundary layers of real emulsion droplets. It is possible to investigate the surface properties of particles in air and fluids at defined temperatures in the range between -15 °C and 120 °C.

This means that, in the future, many questions may be solved, among them:

• How does the processing change the surface structure of particles (e.g. sugar, cocoa, milk powder)?
• Are there polarity differences on particle surfaces and which emulsifiers with different HLB values are preferably adsorbed?
• Are there charge differences at particle surfaces and how do particles interact with each other?
• How does the composition of rheological properties change in the boundary layers of real droplets in emulsions?
• Which substances will adsorb at the surface of ice crystals?

This method will contribute to an increased understanding of the correlation between structure and matrix properties and to a better utilization of these findings for the design of products and processes.

The scanning force microscope at the DIL was supplied by the Asylum Research company via its European representative Atomic Force. The investment could be achieved thanks to the financial support by the county of Osnabrück.

Links:

www.asylumresearch.com
www.atomicforce.de 

For an overview on the service range of the center of food physics available to customers, please click here.