After 29 h of settling, the layered ∆ƒ contrast parallel to the mica substrates was visualized on the 2D ∆ƒ map (Figure ). This layered contrast corresponds to the periodic oscillation of the ∆ƒ-z curves (Figure (b)), and their period was about 0.7-0.9 nm. This period is roughly equal to the diameter of PDMS molecular chains and matches the distance between the molecular chains of 3170 mPa•s PDMS obtained from the theoretical calculation (PRISM; polymer reference interaction site model), molecular dynamics simulation, and X-ray diffraction . It also corresponds to the interplanar spacing of cold-crystallized PDMS with a viscosity (25 ℃) of 3060, 13700 mPa•s .