A NEW TECHNIQUE FOR MEMBRANE CHARACTERIZATION - DIRECT MEASUREMENT OFTHE FORCE OF ADHESION OF A SINGLE-PARTICLE USING AN ATOMIC-FORCE MICROSCOPE

An Atomic Force Microscope (AFM) has been used to quantify directly th e adhesive force between a colloid probe and two polymeric ultrafiltra tion membranes of similar MWCO (4000 Dal but different materials (ES 4 04 and XP 117, PCI Membrane Systems (UK)), The colloid probe was made from a polystyrene sphere (diameter 11 mu m) glued to a V shaped AFM c antilever. Measurements were made in 10(-2) M NaCl solution at pH 8. I t was found that the adhesive force at the ES 404 membrane was more th an five times greater than that at the XP 117 membrane, As it allows d irect quantification of particle/membrane interactions, this technique should be invaluable in the development of new membrane materials and in the elucidation of process behaviour. (C) 1998 Elsevier Science B. V.