ELECTRICAL-CONDUCTIVITY SFM STUDY OF AN ULTRAFILTRATION MEMBRANE

A method for local investigation of ultrafiltration membrane pore netw orks has been developed in order to complement bulk measurements and c alculations. An Anopore(TM) membrane (200 nm) pore network was filled with electrodeposited nickel. Membranes were analysed simultaneously w ith normal scanning force microscopy (SFM) and electrical-conductivity SFM. Cantilevers coated with 10 Omega cm diamond were used to map bot h normal force and conductivity. Conductivity images show two kinds of pores: bright pores with diameters of 192 +/- 2 nm and grey pores wit h diameters of 172 +/- 5 nm, depending on the depth of the nickel tube s. The average pore diameter measured from the normal SFM images is 21 7 +/- 3 nm, and the ratio of the conductive pores to total number of p ores is 49.8%. Preferential flow paths can be established from this te chnique.