AFM System for the Characterisation of Polymeric and Biological Materials

JPK Instruments is pleased to report on the research work from the Chemical Physics group of Professor Robert Magerle of the Chemnitz University of Technology.

The Chemical Physics Group is part of the Faculty of Natural Sciences. The main research topic is the study of the structure and properties of polymeric materials. Within this, Professor Magerle's goals are to learn about structure, structureformation processes and properties of both polymeric and biological materials (bone and other collagen based materials) on the nanometer scale. One general lines of research is imaging structure formation processes in these materials in their native state, where the materials are soft or even fluid.

The discovery of new phenomena on the nanometer scale is vital for progress in research and technology. The use of atomic force microscopy, AFM, provides unique opportunities for the study of soft materials including polymers, polymer melts and solutions. It is also well suited for the study of biological materials.

For this purpose, Professor Magerle's group developed a microtensile testing setup that allows imaging with AFM local deformation processes in thin polymer films. With this new setup the group discovered locally auxetic behaviour in a thin film of elastomeric polypropylene. This unusual property, which causes the material to expand when it is stretched, appears to be an intrinsic property of certain semi-crystalline polymers.

Having used a variety of different types of AFM in his earlier work, Professor Magerle saw many advantages in moving to the JPK NanoWizard® AFM. Speaking on this, Professor Magerle said: "We have chosen the NanoWizard® AFM since it is a tip-scanning system and allows us to place our homebuilt microtensile testing setup precisely below the AFM tip.”

JPK has provided us with a custom-built base-plate with an extra cut-out in the centre so we could mount our microtensile testing setup. Another aspect I like about the NanoWizard® is its solid mechanical design with a tripod. It is very stable with very little thermal drift. Furthermore, the NanoWizard® can be combined with an optical microscope which we intend to use in future projects."