Characterisation and quantification of membrane surface properties using atomic force microscopy: A comprehensive review

In recent years the technique of atomic force microscopy (AFM) has demonstrated a versatility in the characterisation of surface morphology and interaction forces. It is a high resolution imaging technique, using a sharp probe as a stylus to feel the surface in three dimensions to sub-nanometre resolution and which can work in air or liquid environments with no special surface preparation. It can also be used to probe the interaction forces between opposing surfaces, detecting both long range and adhesive interactions. It's wide range of application make it a versatile tool for the study and characterisation of membrane surfaces, not just through production of high resolution imaging, but through the production of quantitative data such as surface roughness, surface pore size and pore size distribution and quantification of foulant - membrane interaction forces. This latter is of great value in assessing the fouling propensity of surfaces with different foulants and under different conditions. This review covers the technique of AFM and its application to the characterisation of membrane surfaces.