Rockwell International Corporation

Paul R Newman

Leslie F Warren, Jr

Edward F Witucki

Patricia H Cunningham

An electrically conductive structural composite which can be heated by application of an electrical current. The structural composite includes a plurality of layers of structural fabric which have been treated and prepreged with a laminating resin and cured into a laminate structure. At least one of the layers of fabric is rendered conductive by being treated with conductive polymer produced by the steps of contacting an electrically insulating porous structural fabric with a liquid pyrrole; contacting the electrically insulating porous structural fabric with a solution of a strong oxidant capable of oxidizing pyrrole to a pyrrole polymer; and, oxidizing the pyrrole by the strong oxidant in the presence of a substantially non-nucleophilic anion and precipitating a conductive pyrrole polymer in the pores of the structural fabric. Electrical conducting means in electrical contact with the conductive layer are utilized for providing passage of electrical current for joule heating of the structural composite. The structural composite has been found to be particularly useful as an airplane surface which is capable of anti-icing and de-icing.

Electrically heated structural composite and method of its manufacture

A conductive or semiconductive pattern of a metal sulfide or selenide such as copper, cadmium, cobalt or nickel sulfide, is provided on a substrate. The pattern may have a resistivity in the range of 1 to 10.sup.6 ohms per square. It is formed by coating the surface with a solution containing a salt of one of the metals which is capable of being converted to a divalent metal compound, a sulfur group donor such as thiourea, and a solvent such as methanol or water. The solution is dried, and then selected portions of the coated surface are irradiated with a laser beam. This thermally converts the irradiated metal salt into a metal sulfide. The unreacted solution is then washed from the substrate to leave a conductive pattern. The desired conductivity of the pattern can be obtained by selecting the proper metal salt, concentration of salt in the solution, and the energy of the radiation.

Laser generated electrically conductive pattern

A method of stabilizing electrically conductive polymers to hostile environments is disclosed. The method comprises encapsulating the conductive polymer, e.g., polypyrrole or polyaniline, as a powder, a free-standing film or preferably in the form of a composite of a substrate, such as fiberglass fabric, impregnated with the conductive polymer, with a suitable resin, preferably an epoxy resin, as an encapsulating agent. The preferred method involves pre-pregging the fabric of the conductive composite with an epoxy resin and curing the resulting system.

Method of stabilizing conductive polymers

Production of electrically conductive composites comprising a dielectric porous substance, e.g., fiberglass fabric, and a pyrrole polymer in the pores of such substance, by treating the porous substance with a liquid pyrrole, and then treating the resulting porous substance with a solution of a strong oxidant in the presence of a non-nucleophilic anion, such as ferric chloride. The pyrrole monomer is oxidized to a pyrrole polymer, which precipitates in the interstices of the porous material. Alternatively, the dielectric porous material can first be treated with a solution of strong oxidant and non-nucleophilic anion followed by treatment with liquid pyrrole, to precipitate an electrically conductive polypyrrole in the pores of the material. The resulting composite of porous material, e.g., fiberglass fabric, containing polypyrrole is electrically conductive while the other properties of such impregnated conductive porous material are substantially unaffected. Several treatments of the porous substance with the pyrrole and oxidant solutions can be carried out to increase the electrical conductivity of the composite.

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Newbury Park, CA, United States of America

Paul R Newman