AFM and Development of (Bio)Fouling-Resistant Membranes

This chapter summarizes some of the literature pertaining to the adhesion of colloids and bio-colloids to membrane surfaces as studied using atomic force microscopy (AFM) techniques. The chapter then concentrates on two more detailed examples in which the AFM is used to characterize the physical and adhesive properties of membranes, which are developed specifically to reduce fouling. It also discusses the contribution that AFM may make in the development of biofouling-resistant filtration membranes. The ability to image the 3D topography of the membrane surface allows quantitative assessment of both roughness and pore size distribution (PSD). Measurement of roughness before and after the use of a membrane gives a quantitative measure of the degree of fouling on the membrane and allows comparison between different membranes. The PSD gives an indication of porosity, which complements observations that may be made using other techniques. The ability of the AFM to use the colloid probe technique to directly assess the interaction forces between colloids and membrane surfaces under different conditions is of great use when it comes to assessing the capability of newly developed membranes to reject fouling particulates.