Rockwell International Corporation

William P Moran

Edward F Witucki

Patricia H Cunningham

Lyle V Monney

The invention is a method of forming a conductive coating on a structural substrate. The method involves depositing a relatively non-conductive precursor material in a solution state on the structural substrate using inkjet apparatus. The solution is dried to leave a film. Then, the dried film is heated to a level at which a chemical (pyrolysis) reaction is triggered to convert the dried precursor material to a conductive material. The precursor solution can be dried in a manner which does not result in its transformation to the conductive state, as for example through the use of microwave apparatus. The precursor material can be applied on the substrate in such a manner as to control the conductivity of the coating and to provide a coating which exhibits one of uniform characteristics, discrete patterns, or gradient characteristics.

Method for producing resistive gradients on substrates and articles

A method for stabilizing shelf life conductivity of conductive coatings such as polypyrrole or nickel sulfide on a substrate such as fiberglass, by incorporating in such conductive coating a polyphenol or a polysiloxane. The polyphenol is derived from a phenolic material in the form of a phenol-formaldehyde monomer or an oligomer of phenol-formaldehyde, and the polysiloxane is derived from a siloxane. Upon heating, the phenolic material cures to a polyphenol and the siloxane is converted to a polysiloxane, forming the stabilizing material on the conductive polypyrrole or nickel sulfide coated substrate. The phenolic material is preferably incorporated directly into the solution formulation for preparing the conductive nickel sulfide or polypyrrole on the substrate, and the polyphenol stabilizer is formed together with the conductive coating on the substrate by heating. In the case of the silane or siloxane material, the conductive polypyrrole or nickel sulfide preferably is formed first on the substrate, and the conductive coated substrate is contacted with a solution of the siloxane followed by heating to convert the siloxane to a polysiloxane protective overcoating.

Stabilizing shelf life conductivity of conductive substrate coatings

Precursor formulation for producing conductive coatings, e.g. nickel sulfide, on substrates such as fiberglass, comprising a soluble metal salt such as nickel acetate, a sulfur donor such as thiourea, a suitable solvent such as water or methanol, and a thickening agent to increase the viscosity of the precursor solution, such as the polyester formed by incorporating ethylene glycol and citric acid, or by addition of xanthan gum, into the precursor formulation. By employing a combination of xanthan gum and locust bean gum the precursor solution can be converted to a gel form. The conversion of the precursor composition into a thickened or gelled form facilitates its application in desired amount and without undue evaporation of solvent, onto a preselected area of the substrate, to form conductive patterns or gradients by various printing processes such as the gravure and transfer processes. Upon heating the coated substrate to a temperature which reacts the metal salt and the sulfur donor of the precursor coating to form the conductive metal sulfide, e.g. nickel sulfide, on the substrate, the polyester or gum additive is pyrolyzed and is substantially removed from the conductive coating.

Formation of inorganic conductive coatings on substrates

A method for stabilizing shelf life conductivity of conductive coatings such as polypyrrole or nickel sulfide on a substrate such as fiberglass, by incorporating in such conductive coating a polyphenol or a polysiloxane. The polyphenol is derived from a phenolic material in the form of a phenol-formaldehyde monomer or an oligomer of phenolformaldehyde, and the polysiloxane is derived from a siloxane. Upon heating, the phenolic material cures to a polyphenol and the siloxane is converted to a polysiloxane, forming the stabilizing material on the conductive polypyrrole or nickel sulfide coated substrate. The phenolic material is preferably incorporated directly into the solution formulation for preparing the conductive nickel sulfide or polypyrrole on the substrate, and the polyphenol stabilizer is formed together with the conductive coating on the substrate by heating. In the case of the silane or siloxane material, the conductive polypyrrole or nickel sulfide preferably is formed first on the substrate, and the conductive coated substrate is contacted with a solution of the siloxane followed by heating to convert the siloxane to a polysiloxane protective overcoating.

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Tulsa, OK, United States of America

William P Moran