Polystyrene-polybutadiene, phase separated.
Image size 9 x 9 um

Polystyrene (PS) and polybutadiene (PB) were mixed and spun onto a silicon wafer. Gradually the two components separate into distinct phases. Scanning with AFM reveals that the PS (the harder material) forms the ridges, whereas, the PB forms he low-lying areas topographically. Annealing the sample remixes the phases.