Type: 2D/3D Analysis

Overview

AFM is a scanning probe technique used for high-resolution surface investigation at the micrometre and nanometre scale. It involves scanning a probe tip situated on the end of  a flexible cantilever across the sample surface and  measuring the attractive or repulsive forces between the  tip and the sample. AFM is capable of acquiring images with little or no sample preparation and is particularly suited for the generation of images indicating changes in surface roughness, of pigment particle size differences, polymer films, binder compositions, dispersing agents, surfactants etc.  For paint films it can offer indicators of degrade due to morphology changes as well as surface modifications on wet-surface cleaning treatments.

Technical details

Images are collected with a nanosurf easyScan DFM.  Scans are made using a POINTPROBE Silicon SPM- Sensor, Al-coating cantilever (nanoworld). The scans can be treated and analysed with SPIP software (Image Metrology) and reported in 3D visualization in grey scale, where the darker colours correspond with deeper regions and bright colours with higher regions.

In situ measurements (as observed below) can be collected by positioning an artwork in a supported horizontal position minimizing vibrational noise as much as possible, and the AFM scan head (weight 350g)  can be carefully placed onto the surface. In the absence of more sophisticated vibration damping methods in the instrumental set-up, the AFM images obtained from these tests included vibration-derived artefacts, which are visible as banding patterns.

Further readings

1. E. Kampasakali, B. Ormsby, A. Cosentino, C. Miliani, T. Learner, A preliminary evaluation of the surfaces of acrili emulsion paint films and the effects of wet-cleaning by Atomic Force Microscopy (AFM), Studies in Conservation, 56 (2011) 216-230

Providers

MOLAB Italy: UNIPG