Using novel synthetic techniques, siloxane-urea segmented copolymers are made. The copolymers advantageously contain a polyether interface, with controlled morphologies and properties. High molecular weight, high strength siloxane-urea copolymers with urea hard segment contents ranging from 5 to over 60% by weight may be prepared. Polymer properties that can independently be controlled include modulus (1.0 to 120 MPa), ultimate tensile strength (1.5 to 25 MPa), level of equilibrium water absorption (˜0 to 100% by weight) and refractive index (1.43 to 1.46).