Durable polyurea copolymer coatings can be applied to surfaces that come in contact with fluids, such as biological fluids, thereby passivating the surface. Polyurea copolymer coating compositions comprise a reaction product of (a) a diamine composition that includes a polyethylene glycol diamine, and optionally, a dipiperidyl alkane; and (b) a diisocyanate. Solutions containing polyurea copolymers, coated surfaces and methods are also described.