Probing Polymer Subsurface Structure Using Tapping Mode Atomic Force Microscopy

Dr. Janelle Gunther

Postdoctoral Associate with STM & ACS groups

28 October 1999

The Atomic Force Microscope is being used in an increasing number of applications to study polymer materials. Using tapping mode AFM, one can go beyond high resolution surface profiling to study local properties, sample composition and underlying surface structure. In this seminar an overview will be presented on tapping mode AFM for studying near surface structure in polymer blends. In tapping mode AFM, the tip-sample interaction is defined by the amplitude of the free oscillating cantilever (Ao) and the setpoint amplitude (Asp). During light tapping (Asp=0.8 to 0.9 Ao) the images most closely reflect the surface topography. However, during hard tapping (Asp=0.4 to 0.5 Ao), tip force induced deformation occurs that can reveal underlying structural and compositional differences. The changes in the height and tapping mode phase images are reversible and do not cause permanent damage to the sample.