Scanning electric potential microscopy imaging of polymers: electrical charge distribution in dielectrics

Scanning electric potential images of polymer surfaces are presented and compared to standard non-contact AFM images. Samples used were a latex film with a well-known distribution of chemical constituents and thus of ionic electrical charges, as well as finished industrial products. Topography and electric potential images show a variable degree of correlation, thus evidencing the independence of topographic and electrical features of the samples, in the micro- and nanoscopic scales. Domains with non-zero negative or positive electric potentials are observed, extending for a few tenths of a micron and creating an electric mosaic in the otherwise neutral polymers. Large electric potential gradients are observed, e.g. in a HDPE film.