Microscopy in non-contact (or resonant) mode
Polymer surface imaging: atomic force microscopy

To avoid tip-surface friction and image the surface of fragile materials, the resonant (non-contact) microscope was developed at virtually the same time as the "classic" contact-mode atomic force microscope [11] . In this case, the tip is located close to the surface, at a distance of the order of 10-100 nm, and is therefore sensitive to longer-range interaction forces of the attractive van der Waals, electrostatic or magnetic type.