Discontinuous conductive filler polymer-matrix composites for electromagnetic shielding
A medical electrical lead having a conductor assembly covered by an insulating layer, and a shield covering positioned adjacent or proximate to at least a portion of the insulating layer in order to shield the conductor assembly from one or more electromagnetic fields. The shield covering is formed of a polymer-matrix composite. The polymer-matrix composite includes a polymeric resin having discontinuous conductive fillers provided therein. The discontinuous conductive fillers include one or more of nano-sized metal structures and nano-sized non-metallic conductive structures. The nano-sized non-metallic conductive structures can have a coating formed of one or more metals. The nano-sized non-metallic conductive structures can be formed of carbon. In turn, the nano-sized non-metallic conductive structures can include one or more of carbon nanofibers, carbon filaments, carbon nanotubes, and carbon nanoflakes.
1. An apparatus for alleviating the adverse effects of various health ailments of a patient comprising:
a medical device; and
an electrical lead connected to the medical device at a proximal end of the lead and having at least a distal end, the distal end of the electrical lead having one or more electrodes or electrical contacts for sensing and/or therapy delivery, the electrical lead comprising a conductor assembly having one or more conductors covered by an insulating layer and the electrical lead further comprising a shield covering adjacent in a radial direction or proximate in the radial direction to at least a portion of the insulating layer to shield the conductors from one or more electromagnetic fields, the shield covering comprising a polymer-matrix composite, the polymer-matrix composite including a polymeric resin having discontinuous conductive fillers provided therein, the discontinuous conductive fillers comprising nano-sized non-metallic conductive structures, the discontinuous conductive fillers being gradiently distributed radially at least within a continuous portion of the polymer-matrix composite with a greater concentration at the surface of the shield covering and being uniformly distributed circumferentially and longitudinally at the surface of the polymer-matrix, the shield covering being circumferentially and longitudinally continuous over an entire length of the shield covering.