Pigment dispersion properties are extremely important for paint, papermaking or plastic industries. To obtain multifunctional features like moisture resistance, antibacterial and self-cleaning properties, the dispersing ability of two alkali-modified styrene-maleic anhydride copolymers (StMa-X, X=Na, K) was studied. It was found that these copolymers showed excellent dispersion action on the M/ZnO (M = Ag, Au and Pt) nanopowders. Sedimentation tests were also performed to observe the compatibility between the M/ZnO nanopowders and copolymers. In addition, an agar plate method was used for the evaluation of antibacterial effect of these materials. Experiments were carried out using the following bacteria: Escherichia coli CCM 3954, Pseudomonas aeruginosa CCM 3955 and Staphylococcus aureus CCM 6188. The quantitative examination of bacterial activity was estimated by the antibacterial rate as calculated from the number of viable cells, which form colonies on the nutrient agar plates. The obtained results are discussed in order to justify their possible application in the field of coating materials with superior properties.