A series of PDMS based Poly(urea-urethane) (PUU) polymers with various polar functional groups on their side chains have been prepared by using a prepolymer process. The hydrophilic and hydrophobic characters of PUU films have been investigated. It was found that PUU film possesses different surface properties on the aluminum contacting face and on the air contacting face. Results show that the differences of contact angles between two sides of the PUU film are very significant. Results also indicate that the silicone/nitrogen ratio on the aluminum-contacting surface is higher than that on the air-contacting surface, and the ratio decreases as the hard segment content increased. It was also found that when the sample was in a dry condition, the electrical surface resistance is in the range of 10(14) Omega However, when the sample was conditioned at 70%, 80% and 100% R. H., the electrical surface resistance decreases to 10(8) Omega. (C) 2003 Kluwer Academic Publishers.