Nanoscale Phase Distribution
A distinct advantage of atomic force microscopy (AFM) is the ability to measure a variety of material properties on the nanoscale simultaneously with topography. For ceramic and composite materials, advanced imaging AFM modes provide mechanical, magnetic, viscoelastic, and piezoelectric properties.
One example is Piezoresponse Force Microscopy (PFM) that is a contact mode to map piezoelectric domains. PFM uses the inverse piezoelectric effect by applying a voltage to use the mechanical response in the material to image the surface. Without the piezoresponse force, domains in a piezoelectric ceramic would not be apparent, as shown below for a lead zirconate titanate (PZT) sample.
Topography (left) and phase (right) signal for a PZT ceramic using PFM.
For composite samples, the phase image from tapping mode reveals material properties. This is illustrated with a simple example of a polymer blend. For this image, the more compliant PMMA is darker compared to the SBR phase.
AFM image of a PMMA/SBR blend, scan size 20 microns.