This invention relates to olefin polymers particularly suited to satisfying the dielectric properties required in electrical device use. The olefin polymers can be prepared by contacting polymerizable olefin monomers with catalyst complexes of Group 3 11 metal cations and noncoordinating or weakly coordinating anion compounds bound directly to the surfaces of finely divided substrate particles or to polymer chains capable of effective suspension or solvation in polymerization solvents or diluents under solution polymerization conditions. Thus, the invention includes polyolefin products prepared by the invention processes, particularly ethylene-containing copolymers, having insignificant levels of mobile, negatively charged particles as detectable by Time of Flight SIMS.