Silicone polyurea block copolymers are prepared by copolymerizing: (a) a diamine composition that includes a polyethylene glycol diamine, and optionally, a dipiperidyl alkane； (b) a monofunctional silicone isocyanate； and (c) a diisocyanate. Compositions useful as passivating coatings comprising the block copolymer are also provided, and substrates coated with the compositions. Methods of preparing and using the compositions are also described.
