Study of the nanoscopic deformation of an annealed nafion film by using atomic force microscopy and a patterned substrate

We demonstrated the repetitive imaging of the same area of a nafion film before and after annealing by using atomic force microscopy (AFM). In order to find the exact same area of the same sample after changing the cantilever and reattaching the sample, a micropatterned substrate was developed. A micropattern with a 250–500 μm pitch was prepared on the backside of a transparent glass substrate. This pattern includes various signs such as colored letters and numbers at the center of each lattice of the pattern. The nanostructures fabricated by AFM nanolithography on a nafion film using this new method were successfully characterized before and after annealing (over 100 °C). The AFM images clearly showed that the nanostructures on a nafion film were dramatically changed by annealing. The data indicated an evidence to understand why the nafion fuel cell does not work well at high temperatures. Our method is probably effective for the study of nanoscopic dynamics in various surface structures.